Black Box Modem 34336 User Manual

AUGUST 1999  
MD885A-R2  
MD885A-R3  
MD885AE-R2  
MD885C-R2  
601745301 Rev. A  
Modem 34336  
34336  
MODEM  
ENT  
3
2
1
3
2
1
NOTE  
All models include the modem, (1) leased line cable, (1) dialup phone cable  
and this user manual. The MD885A-R2, MD885AE-R2, and MD885A-R3  
include a power supply. The MD885A-R3 also includes (1) 10-ft. RS-232  
cable and (1) DB9 F to DB25 M adapter.  
CUSTOMER  
SUPPORT  
INFORMATION  
Order toll-free in the U.S.: Call 877-877-BBOX (outside U.S. call 724-746-5500)  
FREE technical support 24 hours a day, 7 days a week: Call 724-746-5500 or fax 724-746-0746  
Mailing address: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018  
Web site: www.blackbox.com  
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Modem 34336  
Table of Contents  
1.0 Specifications .....................................................................................6  
2.0 Quick Start..........................................................................................8  
2.1 Installation ..................................................................................8  
2.1.1 Unpacking ................................................................................8  
2.1.2 Package Contents......................................................................8  
2.1.3 What You Will Need..................................................................8  
2.1.4 Connections ..............................................................................8  
2.1.5 Jumpers....................................................................................10  
2.2 Front Panel LCD And Controls ..............................................11  
2.2.1 Power-On Screen ...................................................................11  
2.2.2 EIA Status Screen ...................................................................12  
2.3 Quick Setup ..............................................................................13  
2.4 Basic Operation .......................................................................16  
2.4.1 2-Wire Dial (Hayes) Mode .....................................................16  
2.4.2 2-Wire Dial (V.25 bis) Mode ..................................................18  
2.4.3 2-Wire Dial (Dumb) Mode ....................................................19  
2.4.4 Leased Line (2- or 4-Wire) Mode .........................................21  
2.4.5 V.33 Leased Line Operation .................................................22  
2.4.6 2-Wire Dial (Bell 208) Operation .........................................22  
2.4.7 4-Wire Leased Line V.29 Mode..............................................23  
2.4.8 V.29 Fast Master and Slave Modes .........................................24  
2.5 Problem Solving .......................................................................25  
3.0 Modem Setup Options ..................................................................27  
3.1 Methods For Selecting Options ..............................................27  
3.2 Selecting Options From The Front Panel ..............................28  
3.2.1 Pushbuttons And The LCD ...................................................28  
3.2.2 How To Select Options...........................................................29  
3.3 Options .....................................................................................32  
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Table of Contents  
3.3.1 V.42 Error Correction Options .............................................35  
3.3.2 Dialer Mode ...........................................................................41  
3.3.3 Data Format Options .............................................................42  
3.3.4 Disconnect Options ...............................................................43  
3.3.5 Test Options ...........................................................................44  
3.3.6 EIA Options ............................................................................44  
3.3.7 Modem Setups .......................................................................46  
3.3.8 V.33 and BELL 208A/B Options ..........................................49  
3.3.9 Options Accessible With Summary Setup Only ...................50  
4.0 General Operation and Special Features...................................54  
4.1 Quick Reset ..............................................................................54  
4.2 Phone Number Storage ...........................................................54  
4.3 Leased Line Auto-Recovery .....................................................55  
4.3.1 Autodial Backup .....................................................................57  
4.3.2 Exit From Leased Line Auto-Recovery .................................57  
4.3.3 Leased Line Auto-Recovery Options ....................................58  
4.4 Dial Line Auto-Recovery ..........................................................58  
4.4.1 Setting Up The Modem For Dial Line Auto-Recovery .........58  
4.4.2 Recovery Procedure ...............................................................58  
4.5 DTR Dialing .............................................................................60  
4.5.1 Dialing A Stored Number ......................................................60  
4.5.2 Answer Mode Operation .......................................................60  
4.6 Dumb Mode And Bell 208 Operation ....................................60  
4.7 Modem Security Operation .....................................................62  
4.8 Modem-Controlled Remote Control.......................................66  
4.8.1 Direct Modem-to-Modem Remote Control ..........................66  
4.8.2 Remote Control through a Rack Controller.........................67  
4.9 Diagnostic Interface Control ..................................................71  
4.9.1 Diagnostic Port .......................................................................71  
4.9.2 Diagnostic Port Commands ..................................................71  
4.9.3 Responses To Diagnostic Port Commands ...........................73  
4.9.4 DTE Displays ..........................................................................75  
4.9.5 Disconnecting From A Diagnostic Link ...............................75  
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Modem 34336  
4.10 Automatic Fallback ..................................................................76  
4.10.1 Operating Mode Fallback ......................................................76  
4.10.2 V.32 Speed Fallback ...............................................................78  
4.11 V. 13 Operation ........................................................................80  
5.0 Hayes Emulation Mode .................................................................81  
5.1 Hayes Mode Autodialer ...........................................................81  
5.1.1 Enabling The Hayes Mode Autodialer .................................81  
5.1.2 Command Guidelines ............................................................81  
5.1.3 Result Codes ...........................................................................84  
5.1.4 Transmission Speed ...............................................................84  
5.2 Hayes Compatible Commands ................................................84  
5.3 S Registers ................................................................................90  
5.3.1 Reading And Setting Registers ..............................................86  
5.3.2 S Register Functions ..............................................................86  
5.4 Selecting Options In Hayes Mode ..........................................94  
5.4.1 Saving Option Selections .......................................................94  
5.4.2 Profile 0 and Profile 1.............................................................94  
5.5 Hayes Mode Reference Tables ................................................95  
6.0 V.25 bis Autodialer .......................................................................107  
6.1 Enabling The V.25 bis Autodialer .........................................107  
6.2 V.25 bis Autodialer Commands ............................................108  
6.3 Dialing Parameters ................................................................112  
6.4 V.25 bis Result Codes .............................................................112  
6.5 DTR Dialing In V.25 bis Mode ..............................................112  
7.0 Diagnostics......................................................................................113  
7.1 When And Why To Test ........................................................113  
7.2 Symptoms And Scope Of The Problem ...............................113  
7.3 Physical Inspection ................................................................114  
7.4 Overview Of Modem Diagnostics ..........................................114  
7.5 How To Select And Activate Tests ........................................115  
7.5.1 Front-Panel Control .............................................................115  
7.5.2 Running Tests In Hayes Mode.............................................115  
7.5.3 Remote Test Control ...........................................................115  
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Table of Conents  
7.6 Diagnostic Monitoring: Status Screens .................................115  
7.6.1 EIA Status Screen .................................................................115  
7.6.2 Other Status Screens.............................................................116  
7.7 Local Modem Diagnostics......................................................118  
7.7.1 Analog Loopback (ALB) Test .............................................118  
7.7.2 Analog Loopback Self Test (ALBST) .................................119  
7.7.3 Analog Loopback Self Test With Errors (ST/E) ...............120  
7.7.4 External Analog Loopback (ALBX) Test ...........................121  
7.7.5 External Analog Loopback Self Test (ALXST)...................123  
7.7.6 Digital Loopback Test (DLB) .............................................124  
7.8 Remote Modem Diagnostics......................................................126  
7.8.1 Remote Digital Loopback (RDL) Test ...............................126  
7.8.2 Remote Digital Loopback Self Test (RDLST) ....................127  
Appendix A: DB25 Pin Assignments..........................................................129  
Appendix B: Quick Setup Configurations .............................................130  
Appendix C: Summary Setup .......................................................................135  
Appendix D: Jumpers ......................................................................................144  
Appendix E: LCD Flow Charts ....................................................................147  
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Modem 34336  
1.0 Specifications  
Available Configurations —  
Compatibility —  
Stand-alone or rack-mount  
V.29  
9600, 7200, 4800  
V.32 terbo  
V.33  
19.2 or 16.8 kbps  
14.4 or 12.0 kbps  
14.4, 12.0, 9.6, 7.2, or 4.8 kbps  
9.6 or 4.8 Kbps  
V.32 bis  
V.32  
V.34+  
33.6, 31.2, 28.8, 26.4, 24, 21.6, 19.2,  
16.8, 14.4, and 12 kbps, 9600, 7200,  
4800, and 2400 bps  
V.34  
28.8, 26.4, 24, 21.6, 19.2, 16.8, 14.4,  
and 12 Kbps, 9600, 7200, 4800, and  
2400 bps  
V.22 bis  
V.21  
2.4 kbps,  
300 bps  
Bell 208A/B 4.8 kbps  
Bell 212A  
Bell 103  
1.2 kbps  
0 to 300 bps  
Data Rates —  
Data Format —  
Operation —  
Fallback —  
Asynchronous: 300 to 19,200 bps  
Synchronous: 600 to 19,200 bps  
Asynchronous: 9, 10, or 11 bits, serial, binary  
Synchronous: Serial, binary  
Full duplex over dialup or leased line  
Simulated half duplex V.13 operation  
Data Rates: 16.8, 14.4, 12.0, 9.6, 7.2, 4.8,  
2.4, 1.2, or 0.3 kbps  
Operation: V.22 bis, V.22, V.21, or V.23  
Supported DTE Speeds —  
Modes —  
300 to 115,200 bps  
V.34+  
33.6, 31.2, 28.8, 26.4, 24, 21.6, 19.2, 16.8,  
14.4, and 12 kbps, 9600, 7200, 4800, and  
2400 bps; full duplex over 2-wire line  
(Trellis coded)  
V.34  
QAM at 28.8, 26.4, 24, 21.6, 19.2, 16.8,  
14.4, and 12 kbps, 9600, 7200, 4800, and  
2400 bps; full duplex over 2-wire line  
(Trellis coded)  
V.34 Extended AT: 33.6 Kbps, TR-301 proposed  
V.32 terbo QAM at 19.2 and 16.8 Kbps; V.32bis  
fallback at 14.4 Kbps and lower  
V.33  
QAM Trellis coded at 14.4 and 12.0 Kbps  
V.32 bis QAM at 14.4, 12.0, 9.6, 7.2, and 4.8  
V.32  
Kbps; echo cancel, full duplex over  
2-wire line (Trellis coded at 7.2 Kbps and  
higher, or non-coded at 9.6 Kbps)  
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1.0 Specifications  
V.29  
V.27  
V.26  
V.23  
QAM at 9600, 7200, and 4800 bps  
8-phase DPSK at 4800 and 2400 bps  
4-phase DPSK at 2400 and 1200 bps  
FSK at 1200/75 bps, full duplex  
V.22 bis: QAM at 2400 bps; bandsplit, full duplex  
V.22:  
V.21:  
DPSK at 1200 bps; bandsplit, full duplex  
PSK at 0 to 300 bps; bandsplit, full duplex  
Autodialer —  
Automatic dialing using rotary pulses or tone  
signaling; supports Hayes AT commands or  
V.25 bis commands  
Answer Modes —  
Equalization —  
Automatic and manual answer  
Receiver:  
Automatic adaptive equalization  
Transmitter: Selectable compromise equalization  
(4 types)  
Line Requirement —  
Transmit Timing —  
Transmit Level —  
Unconditioned  
Internal, external, or slaved to receive clock  
Leased:  
Dial:  
Selectable, 0 to -15 dBm  
Permissive or programmable  
Interface —  
Terminal:  
RS-232C/D, CCITT V.24/V.28  
Dialup Line: 8-pin RJ-45 modular connector with  
A/A1 and MI/MIC control  
Leased Line: 6-pin RJ-11 modular connector  
Diagnostic:  
8-pin RJ-45 modular connector  
Carrier Detect Threshold —  
Test Capabilities —  
Leased line: -26, -33, or -43 dBm; selectable  
Dial line: -34, 41, or -51 dBm; selectable  
Analog loopback, analog loopback self-test,  
self-test with errors, digital loopback, remote  
digital loo.pback self-test, external analog  
loopback (4-wire), external analog loopback  
self-test (4-wire); front-panel TIA/EIA or front-  
panel Hayes control  
AC Power —  
Stand-alone: 90-132 VAC, 60 Hz 5%  
Rackmount: 117/220 VAC  
Power Consumption —  
Heat Generation —  
Ringer Equivalence —  
Environment —  
13 watts  
44 BTU/hr  
0.7 B  
Ambient temp:  
32 to 120°F (0 to 49°C)  
Storage temp.:20 to 180°F (-7 to 82°C)  
Relative humidity: 5 to 90% at 24°C (75°F)  
non-condensing  
Size (stand-alone unit) —  
Weight —  
2.5"H x 9.7"W x 10.1"D (6.4 x 24.6 x 25.7 cm)  
Stand-alone:  
4.1 lb (1.9 kg)  
2 lb. (0.9 kg)  
Rackmount:  
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Modem 34336  
2.0 Quick Start  
All information in this manual applies to both the stand-alone and rack-  
mount versions of the Modem 34336.  
QUICK SETUPS FOR A QUICK START  
The simplest and fastest way to set up the Modems for immediate use is to  
select one of the factory-preset Quick Setup configurations.  
Quick Setups are explained in Section 2.3, following installation instructions  
(Section 2.1) and a brief introduction to the Modem’s front-panel display and  
controls (Section 2.2).  
2.1 Installation  
2.1.1 UNPACKING  
Many early modem failures are a result of damage done during shipping.  
Visually inspect your modem. Keep the original shipping carton in case  
you have to return the modem for any reason.  
2.1.2 PACKAGE CONTENTS  
All models include the following cables:  
• A two-conductor crossover cable for a dial-line connection.  
• A four-conductor cable for a leased-line connection.  
Both cables have an eight-pin modular connector (RJ-45) on one end and  
a six-pin modular connector (RJ-12) on the other end. You will need to use  
both of the supplied cables if you want to use the Modem for Leased-Line  
Auto Recovery, which requires both a leased-line and dial-line connection.  
The MD885A-R2, MD885AE-R2, and MD885A-R3 include a power supply.  
The MD885A-R3 package also includes additional cables:  
• (1) 10-ft. RS-232 cable  
• (1) DB9 F to DB25 M adapter  
2.1.3 WHAT YOU WILL NEED  
• You will need an EIA RS-232 interface cable (supplied with the MD885A-  
R3, not supplied with the MD885A-R2, MD885AE-R2, or MD885C-R2) to  
connect the Modem to a DTE (data terminal equipment, usually a  
computer).  
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2.0 Quick Start  
• If you are operating the Modem in a manual dial mode, you also need  
a standard telephone set.  
2.1.4 CONNECTIONS  
Figure 2-1 shows how the Modem is connected to the computer or terminal,  
AC power supply, phone lines, and handset.  
Do not install the modem more than 50 feet (15.2m) from the DTE (the  
EIA standard maximum length for interface cable). For DTE speeds greater  
than 19.2 Kbps, a shorter low-capacitance DTE interface cable should be used.  
Call technical support for information on which cable will support your  
application.  
For all applications:  
• Connect your RS-232 cable to the rear-panel DB25 connector labeled  
DTE. Connect the other end to your computer or other DTE.  
• Attach the power transformer cable (included) to the rear-panel  
connector labeled POWER. Plug the other end into an AC outlet.  
POWER  
TX  
DIAL  
RX LEASED  
DIAL LINE PHONE  
DTE  
DIAG  
RS-232  
cable  
Power  
trans-  
former  
Dialup  
Line  
Leased  
Line  
DTE  
Telephone  
AC outlet  
Figure 2-1. Modem 34336 Connections.  
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Modem 34336  
For dialup applications:  
• Use the supplied two-conductor crossover cable to connect the Modem  
to the telephone-line modular wall jack. Plug the eight-pin connector  
(RJ-45) of the cable into the rear-panel jack labeled TX DIAL. Then,  
plug the six-pin connector (RJ-12) into the telephone jack.  
NOTE  
Do not bundle the telephone and RS-232 cables together.  
• Optional: For manual-dial operation, or if you want to use the telephone  
line for voice transmissions (when the Modem is not operating in data  
mode), connect a standard telephone into the rear-panel jack labeled  
PHONE.  
For leased-line applications:  
• Use the supplied four-conductor cable to connect the Modem to your  
leased-line modular wall jack. Attach the six-pin modular connector  
(RJ-12) to the rear-panel jack labeled LEASED LINE. Attach the eight-pin  
connecter (RJ-45) of the cable into the line’s terminal block.  
The same cable is used whether you have a 4-wire or 2-wire leased line. In  
a 4-wire application, the green and red wires are the TRANSMIT pair, and  
the yellow and black wires are the RECEIVE pair. When the cable is  
connected to a 2-wire line, only the green and red wires are used.  
NOTE  
Do not bundle the telephone and RS-232 cables together.  
2.1.5 JUMPERS  
For most applications, you will not need to reset internal jumpers. However,  
jumpers must be reset for the following situations:  
• If you are connecting frame ground to signal ground.  
• If you are switching from A/A1 control to MI/MIC control.  
• Change the function of TIA/EIA pin 25 (the default is test mode  
indicator).  
• If you use the Modem in a DC rack enclosure.  
For detailed jumper information, see Appendix D.  
10  
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2.0 Quick Start  
2.2 Front-Panel LCD and Controls  
To select a Quick Setup configuration, you will need to use the pushbuttons  
and liquid-crystal display (LCD) on the modem’s front panel. These features  
are shown in Figure 2-2. For a detailed explanation of the front panel  
controls, see Chapter 3.  
2.2.1 POWER-ON SCREEN  
When the Modem is powered on, the LCD momentarily displays the power-on  
screen. The top line identifies the modem type. The lower line indicates the  
software revision level.  
NOTE  
The software revision level of your modem may be different from the  
number shown above.  
The Modem spends about two seconds checking the ROM checksum and  
doing self-tests, and then displays the EIA status screen.  
V.34/33.6  
Version  
3.01  
1
2
3
1
2
3
1
2
3
ENT  
FRONT PANEL  
PUSHBUTTONS  
LIQUID CRYSTAL DISPLAY (LCD)  
Figure 2-2. Front-Panel LCD and Controls.  
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Modem 34336  
2.2.2 EIA STATUS SCREEN  
The EIA status screen indicates the operational status of the Modem as well  
as the condition of certain EIA RS-232 leads. The abbreviations that may  
appear are identified below. Typically, only a few of these abbreviations  
will be displayed during actual operation.  
D TR MR RS CS  
9600  
CD  
1
2
3
D
R
S
=
=
=
Dial line occupied.  
Ringing (R appears in same position as D).  
Connection secured by security handshake. (S appears in same  
position as D. S and D may flash alternately).  
TR = Data Terminal Ready.  
MR = Data Set Ready.  
RS = Request to Send.  
CS = Clear to Send.  
TD = Transmit Data.  
14.4, 9600, 4800, etc.  
or bps (bits per second) (“idle” or H-01, H-14, etc. may also be  
displayed in the data speed position; see text below).  
= Data speed in Kbps (thousand bits per second)  
TM = Test mode.  
ER = Error (poor signal quality).  
CD = Carrier Detect.  
RD = Receive Data.  
Codes beginning with H (such as H-01) in the lower left corner of the status  
screen indicate that the Modem is handshaking with another modem  
(attempting to establish a connection).  
When the modem is off-line, the word “idle” is displayed in the lower left  
corner of the status screen.  
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2.0 Quick Start  
2.3 Quick Setup  
To set up the Modem for immediate use (or to quickly change the modem’s  
configuration for an alternate mode of operation), select one of the factory-  
preset Quick Setup configurations (see Table 2-1). Your Modem will be ready  
for operation. You will not need to make further adjustments.  
When you select a Quick Setup, the Modem uses internal memory to  
automatically set all of its options to the chosen configuration. All  
previously-stored option settings are overwritten. The Quick Setup  
does not affect telephone numbers stored in the modem’s memory.  
You can customize a Quick Setup configuration by changing specific  
option settings (see 3.0 Modem Setup Options).  
HOW  
TO  
SELECT A QUICK SETUP  
To activate a Quick Setup configuration, follow the steps below. As you do,  
you may find it helpful to refer to the LCD flow chart at the back of this  
manual.  
1. Press the ENT (enter) pushbutton on the modem’s front panel.  
Screen 1 of the MAIN MENU is displayed:  
MAIN MENU  
<1>  
TALK QUICK DIAL  
1
2
3
2. Press pushbutton 2. Screen 1 of the QUICK SETUP menu appears:  
QUICK SETUP <01>  
2-W DIAL (Hayes)  
1
2
3
3. Use the front-panel arrow pushbuttons to move through the QUICK  
SETUP menu. There are 12 QUICK SETUP configurations. Each  
configuration is discussed in Table 2-1.  
4. When the LCD shows the Quick Setup configuration you want, press  
pushbutton 2. The bottom line of the display will flash.  
5. Press ENT. You will see SETUP screen 1. Press ENT a second time.  
The modem resets and the selected Quick Setup takes effect.  
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Modem 34336  
All options for each Quick Setup configuration are listed in Appendix B.  
If you want to customize your Quick Setup configuration, see 3.0, Modem  
®
Setup Options. For Hayes mode options, see 5.0, Hayes Emulation Mode.  
Table 2-1. Available Quick Setup Configurations.  
QUICK SETUP  
IDENTIFIED ON LCD  
DESCRIPTION  
QUICK SETUP <01>  
2-W DIAL (Hayes)  
2-WIRE DIAL HAYES EMULATION MODE— This  
dial mode (for use over ordinary phone lines) allows the  
Modem to automatically dial (autodial) a previously  
stored phone number and respond to Hayes commands.  
This mode is compatible with communication software  
packages that use Hayes-style AT commands. The  
Hayes mode Quick Setup is the factory default  
configuration for the Modem.  
QUICK SETUP <02>  
V25 DIAL (Async)  
2-WIRE DIAL V.25 bis MODE,  
ASYNCHRONOUS—In V.25 bis mode, the Modem  
operates in conformance with CCITT recommendation  
V.25 bis, allowing you to store and direct dial or autodial  
phone numbers from the DTE. Use Quick Setup 2 if the  
DTE connected to the modem is asynchronous.  
QUICK SETUP <03>  
V25 DIAL (Syn_c)  
2-WIRE DIAL V.25 bis MODE, SYNCHRONOUS-  
CHARACTER ORIENTED— Same as Quick Setup 2  
except for data protocol. Use Quick Setup 3 if the DTE is  
synchronous-character oriented (bisynchronous).  
QUICK SETUP <04>  
V25 DIAL (Syn_b)  
2-WIRE DIAL V.25 bis MODE,  
SYNCHRONOUS BIT ORIENTED—Same as Quick  
Setup 2 except for data protocol. Use Quick Setup 4 if  
the DTE is synchronous bit-oriented (SDLC/HDLC).  
QUICK SETUP <05>  
2-W DIAL (DUMB)  
2-WIRE DIAL DUMB MODE—When the Modem is in  
Dumb mode, you can use it for dial-line answer-only  
applications, dial a previously stored telephone number  
from the front panel, or dial telephone numbers via an  
external source (telephone).  
QUICK SETUP <06>  
2-W LEASED (ORG)  
2-WIRE LEASED-LINE ORIGINATE MODE—  
In Leased-Line mode, the Modem connects to the leased  
line and stands ready to send and receive data. Use  
Quick Setup 6 if the leased line is a 2-wire line and you  
want to configure the Modem as the originate modem.  
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2.0 Quick Start  
Table 2-1 (continued). Available Quick Setup Configurations.  
QUICK SETUP <07>  
2-W LEASED (ANS)  
2-WIRE LEASED-LINE ANSWER MODE—  
Same as Quick Setup 6 except for modem answer/ originate  
status. Use Quick Setup 7 if the leased line is a 2-wire line  
and you want to configure the Modem as the answer modem.  
QUICK SETUP <08>  
4-W LEASED (ORG)  
4-WIRE LEASED LINE ORIGINATE MODE—  
Same as Quick Setup 6 except for line type. Use Quick  
Setup 8 if the leased line is a 4-wire line and you want to  
configure the Modem as the originate modem.  
QUICK SETUP <09>  
4-W LEASED (ANS)  
4-WIRE LEASED LINE ANSWER MODE—  
Same as Quick Setup 6 except for line type and modem  
answer/originate status. Use Quick Setup 9 if the leased  
line is a 4-wire line and you want to configure the Modem  
as the answer modem.  
QUICK SETUP <10>  
4-WLL V.33  
V.33 LEASED LINE OPERATION—  
This Quick Setup configures the Modem for V.33  
operation. This provides compatibility with V.33 modems.  
QUICK SETUP <11>  
2-W DIAL (208)  
2-WIRE DIAL BELL 208 OPERATION—  
This Quick Setup configures the Modem for 2-wire dial  
operation compatible with Bell standard 208B.  
QUICK SETUP <12>  
2-W DIAL V32/208  
2-WIRE DIAL V.32/208 AUTO-DETECT MODE—  
This Quick Setup configures the Modem to automatically  
select V.32 bis (V.13) or Bell 208 operation, depending on  
the mode of the originating modem.  
QUICK SETUP <13>  
4-WLL V.29  
4-WIRE LEASED LINE V.29 MODE— This Quick Setup  
configures the modem for V.29 operation, for  
compatibility with V.29 modems.  
QUICK SETUP <14>  
V.29 FAST MASTER  
V.29 FAST MASTER MODE— This Quick Setup con-  
figures the modem for V.29 fast train master operation, for  
use in a multidrop network where multiple remote (slave)  
modems share the master Modem as the host modem.  
QUICK SETUP <15>  
V.29 FAST SLAVE  
V.29 FAST SLAVE MODE — This Quick Setup configures  
the modem for V.29 fast train slave operation, for use in a  
multidrop network where multiple remote (slave) modems  
share the same host (master) modem.  
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Modem 34336  
2.4 Basic Operation  
This section provides basic information for each of the modem’s primary  
operating modes. If you encounter difficulty, refer to Section 2.5, Problem  
Solving.  
2.4.1 2-WIRE DIAL (HAYES) MODE  
(QUICK SETUP 1)  
Two-Wire Dial (Hayes) mode is the factory-default configuration for the  
Modem. Hayes mode operation and commands are explained in detail in 5.0,  
Hayes Emulation Mode.  
Dialing a Phone Number. To dial a telephone number in Hayes mode,  
type the Hayes command  
AT D on your computer or terminal keyboard, followed by the number  
you want to call and <cr>. Example:  
AT D 5551212 <cr>  
Dashes or spaces may be included for clarity, but they are not necessary.  
The Modem ignores them.  
A carriage return (<cr>) is required at the end of each command. On  
most keyboards, the carriage return (<cr>) key is labeled Enter or Return.  
In response to the command line shown above, the Modem will dial the  
number 555-1212.  
If you need an access code (such as 9) to dial out of your building,  
insert the access code and a comma in the dial string:  
AT D 9,5551212 <cr>  
The Modem pauses for 2 seconds at the comma. This allows the Modem to  
wait for a second dial tone (after the access code) before dialing the number.  
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2.0 Quick Start  
Dialing Mode. The default dialing mode is tone dialing. To change to pulse  
dialing, insert a P after AT D:  
AT DP  
To change from pulse dialing to tone dialing, insert a T after AT D:  
AT DT  
The specified dialing mode remains active until the alternate mode is  
specified or the modem is reset.  
Connected. When a phone number is successfully dialed, a CONNECT  
message appears on the computer screen and the LCD on the Modem  
displays a status screen similar to the one shown below.  
D TR MR RS CS TD  
9600  
CD  
RD  
1
2
3
TD and RD flash to indicate that the modem is transmitting and receiving  
data. The speed may be other than 9600 bps. The Modem automatically  
adjusts to the speed of the remote modem, provided the remote unit is a  
compatible modem.  
Terminating a Call. To terminate a call, first enter the escape sequence, +++.  
When the OK response appears on the DTE screen, enter the command AT  
H. An alternate method is to drop the DTR signal from the DTE. If you are  
using a computer with a communication software program, follow the  
program’s instructions for initiating and terminating calls.  
2.4.2 2-WIRE DIAL (V.25 BIS) MODE (QUICK SETUPS 2, 3, AND 4)  
The Modem supports three types of V.25 bis operation: asynchronous,  
character-oriented synchronous, or bit-oriented synchronous. There is a  
Quick Setup for each V.25 bis type.  
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Modem 34336  
For V.25 bis operation, the Modem must be configured to use the same data  
protocol as the attached DTE. V.25 bis mode operation and commands are  
explained in detail in Chapter 6.0, V.25 bis Audodialer.  
Asynchronous V.25 bis Operation.  
The data format of the DTE should be set to 7 data bits with even parity and  
one stop bit. The default DTE interface rate is 38,400 bps in asynchronous  
mode.  
V.25 bis commands can be entered from the DTE keyboard. Example:  
CRN 5551234  
In response to this command, the Modem sends a VAL result code back  
to the DTE (indicating that the command is accepted), dials the telephone  
number 555-1234, and then waits for an answer tone from the remote  
modem. If no carrier is detected within a given time (default is 45 seconds),  
the modem automatically releases the line and sends a CFI NT result code  
to the attached DTE.  
Spaces entered in the command line for clarity are ignored:  
CRN 555 1212 has the same effect as CRN5551212.  
When a phone number is successfully dialed, the EIA status screen  
on the Modem looks like the one shown below.  
D TR MR RS CS  
9600  
CD  
1
2
3
Synchronous V.25 bis Operation  
The data format of the DTE should be set to 7 data bits with odd parity.  
In synchronous applications, the V.25 bis commands can be used to facilitate  
computer-controlled operations.  
Synchronous bit-oriented operation uses High-Level Data Link Control  
(HDLC) formatting.  
Synchronous character-oriented operation uses synchronous start-of-text  
and end-of-text characters to frame messages. The start-of-text character  
is preceded by two synchronous (SY) characters.  
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2.0 Quick Start  
2.4.3 2-WIRE DIAL (DUMB) MODE (QUICK SETUP 5)  
Dumb mode is used primarily for manual call origination, answer-only  
applications, and in conjunction with certain dial back security systems that  
utilize MI/MIC signals to place the modem on-line. (If you need to configure  
the modem for MI/MIC use, refer to Appendix D.) For additional  
information on Dumb-mode operation, refer to Chapter 4.0, General  
Operation and Special Features.  
Answering a Call Automatically. After the Quick Setup for 2-Wire Dial  
(Dumb) mode is selected, the Modem will automatically answer incoming  
calls. The only other requirement is that either (1) the DTE must provide  
the DTR signal (TR on the LCD status screen) to the modem, or (2) DTR  
must be set to TRUE (using the modem’s DTR from EIA option screen).  
Originating a Call from the Front Panel. Before you can originate a call from  
the front panel, you must store the number to be dialed in the modem.  
From the Set-up <5> screen, access the PHONE screen by pressing the  
following pushbuttons in sequence:  
Pushbutton 1 (Phone)  
Pushbutton 2 (Prog)  
The abbreviations DEC, CTRL, and INC are displayed on the bottom line  
of the LCD, indicating that you located the PHONE screen.  
Follow the steps below to store the phone number:  
1. Use the right and left arrow pushbuttons to go to the digit you want to  
change. The cursor causes the character at that digit location to blink,  
indicating that the digit or character can be changed.  
2. Use pushbutton 1 to decrease numbers, and pushbutton 3 to increase  
them.  
3. Use pushbutton 2 (CTRL) to sequence through the dialing control  
characters (explained in Chapter 3).  
4. Use the arrow pushbuttons to move on to the next digit or character  
you want to change. (The characters that can be stored are listed in  
Chapter 3.)  
5. The phone number is saved when you return to the MAIN MENU.  
To return to the EIA status screen, press ENT three times.  
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Modem 34336  
Autodialing the Stored Number. To autodial the stored number from  
the EIA status screen, press the following pushbuttons in sequence:  
ENT  
Pushbutton 3 (to select DIAL from MAIN MENU screen 1)  
Pushbutton 1 (to select DIAL from the AUTO-DIAL screen)  
When the local modem successfully establishes a connection with the remote  
unit, the EIA status screen should be present. This screen looks like the one  
shown below.  
D TR MR RS CS TD  
9600  
CD  
RD  
1
2
3
If the modem’s LCD displays an AUTO-DIAL FAILURE message,  
refer to Table 2-2.  
Terminating a Data Call. Normal termination of a data call is processed  
through communication software. An alternate method is switching the  
HANGUP option on the AUTO-DIAL screen. Another method is to drop  
the DTR signal from the DTE (by software control or by turning the DTE off).  
For manual originate/answer operation, see Chapter 4.  
2.4.4 LEASED LINE (2- OR 4-WIRE) MODE (QUICK SETUPS 6, 7, 8, AND 9)  
This section does not apply to V.33 leased line operation. For V.33 leased line  
operation, see the next section.  
Table 2-2. Auto-Dial Failure Messages.  
FAILURE MESSAGE  
LINE OCCUPIED  
EXPLANATION  
The data line is already in use.  
DIAL NOT ALLOWED  
Modem is not configured for dial  
backup.  
NO DTR  
DTR is not present.  
Loss of line current.  
NO LINE CURR  
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2.0 Quick Start  
The following information applies to both 2-wire and 4-wire leased-line  
operation:  
• The modem must be configured for the correct line type –– 2-wire  
or 4-wire. If you select the correct Leased Line Quick Setup,  
the line type is automatically set to the correct setting.  
• One modem must be set to originate mode and the other to answer mode.  
If you select the correct Leased Line Quick Setup, the answer/originate  
status is automatically set to the correct setting.  
• Leased line operation is restricted to data rates of 4800 bps or higher.  
• Lines can be conditioned or unconditioned.  
After the appropriate Leased Line Quick Setup is selected, the answer unit  
immediately begins the training sequence. It is ready to handshake with  
the originate modem.  
When the local modem establishes a connection with the remote unit, the  
EIA status screen should be present. This screen should look like the one  
shown below.  
TR MR RS CS TD  
9600  
CD RD  
1
2
3
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Modem 34336  
2.4.5 V.33 LEASED-LINE OPERATION (QUICK SETUP 10)  
V.33 operation is available on the Modem at speeds of 12,000 and 14,400 bps.  
V.33 leased-line operation provides compatibility with V.33 modems  
(synchronous operation only).  
A 4-wire line must be used (conditioned or unconditioned), and both  
connected modems must be set for V.33 operation.  
After the V.33 Leased-Line Quick Setup is selected, the answer unit  
immediately begins the training sequence, meaning it is ready to handshake  
with the originate modem.  
When the local modem successfully establishes a connection with the remote  
unit, the EIA status screen is present. This screen looks like the one shown  
below:  
TR MR RS CS TD  
9600  
CD RD  
1
2
3
Three options are intended for V.33 (and Bell 208A/B) operation exclusively.  
These options are listed in Section 3.3.8.  
2.4.6 2-WIRE DIAL (BELL 208) OPERATION (QUICK SETUPS 11 AND 12)  
The Bell 208 Quick Setup, available on the Modem only, configures the  
modem for 2-wire dial synchronous operation compatible with Bell standard  
208B. The data rate is fixed at 4800 bps, and the data format is set to  
synchronous. Both connected modems must be set for 208B operation.  
For additional information on Bell 208 operation, see Chapter 4.  
Beginning with the section titled Answering a Call Automatically,  
all information in Section 2.4.3 also applies to Bell 208 operation.  
Three options are intended for Bell 208 (and V.33) operation exclusively.  
These options are listed in Section 3.3.8.  
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2.0 Quick Start  
2.4.7 4-WIRE LEASED LINE V.29 MODE (QUICK SETUP 13)  
The 4-Wire Leased Line V.29 Mode configures the modem for V.29  
operation, for compatibility with V.29 modems. Keep these guidelines  
in mind when using this mode:  
• The modem must be configured for use with a 4-wire line.  
• Operation is restricted to data rates of 4800, 7200, and 9600 bps.  
• Lines can be conditioned or unconditioned.  
After you select this Quick Setup mode, the modem will send a training  
sequence and wait for a training response from the remote modem. The  
modem will repeat the training sequence every 1.2 seconds until the remote  
modem responds.  
When the local modem has established a connection with the remote unit,  
the TIE/EIA status screen will appear.  
NOTE  
For point-to-point 4-wire leased-line V.29 operation, the Auto-Retrain  
option should be enabled on both modems. (Auto-Retrain is enabled by  
default if you select the 4-wire Leased Line V.29 Quick Setup.) If the  
Auto-Retrain option is disabled, the modem will not transmit a training  
sequence and will instead train on the data stream from the remote  
modem. Disabling Auto-Retrain in 4-wire leased line V.29 mode is  
recommended for test purposes only. If Auto-Retrain is disabled, it  
should be disabled on both modems.  
V.34/V.32 Dial Backup  
NOTE  
Dial backup can only be used in point-to-point applications.  
To prevent service interruption in the event of poor leased line conditions,  
the modem can be configured for V.29 leased line operation with V.34/V.32  
dial backup. This means the modem will use dial lines to automatically restore  
operation when conditions on the leased lines deteriorate. (Use V.34 or V.32  
modulation for dial backup.) To set up the Modem for V.29 leased line  
operation with dial backup, follow these steps:  
1) Select the 4-wire leased line V.29 (4-WLL V.29) Quick Setup on both the  
local and remote modem.  
2) One modem must be set to originate mode and the other to answer mode.  
To make this selection, use the ANS/ORG DEFAULT screen on the front  
panel LCD.  
3) Configure the modems for leased line auto-recovery.  
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Modem 34336  
2.4.8 V.29 FAST MASTER AND SLAVE MODES (QUICK SETUPS 14 AND 15)  
In multidrop operation, the master modem transmits to all of the slave  
(remote) modems. When the DTE at a slave site recognizes its own address in  
the polling protocol, it raises RTS to the slave transmitter. The slave responds  
by transmitting a special training sequence, then raising CTS and transmitting  
the data from the DTE. When the DTE has completed transmission, it lowers  
RTS and the modem will drop carrier to let the next modem on the poll list  
use the channel.  
The V.29 Fast Master and Fast Slave modes support data rates of 4800, 7200,  
and 9600 bps. The leased lines can be conditioned or unconditioned. The  
master modem must be set to originate mode, and the slave modem must be  
set to answer the mode. (The Answer/Originate option is automatically set to  
these settings when the V.29 Fast Master and Fast Slave Quick Setups are  
used.)  
Slave-to-Master (Inbound) Transmission  
When the remote modems come on-line, they automatically synchronize to  
the incoming carrier and train on the data stream from the master modem.  
Slave-to-master transmission is always switched carrier operation under  
control of the RTS signal from the DTE. An anti-streaming timer built into  
the modem will (if enabled) halt transmission if the DTE holds RTS on for  
more than 30 seconds. The assumption is that if RTS is held on for more  
than 30 seconds, there is a fault in the DTE.  
If you access the TIA/EIA status screen on the LCD display when a slave  
modem is transmitting to the master modem, the status screen will typically  
look like this:  
TR MR RS CS TD  
9600  
CD RD  
Typically TD, CD, and RD will flash on the master modem, and RS, CS, TD,  
and RD will flash on the slave modems.  
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2.0 Quick Start  
2.5 Problem Solving  
If you encounter difficulties in setting up or using the modem, try the  
remedies described below. If you suspect a system malfunction, follow the  
diagnostic procedures described in Chapter 7. If you cannot resolve the  
problem, call your supplier.  
1. ALL MODES  
Make sure all cables are properly connected to the back of the modem.  
2. ALL DIAL MODES (HAYES, V.25 BIS, DUMB, BELL 208, AND V.32/208)  
DTR (Data Terminal Ready) must be ON if you want to use the modem’s  
autodial or auto-answer features. (If DTR is ON, the TR indicator is present  
on the EIA status screen.)  
3. ALL ASYNCHRONOUS MODES  
The modem’s default DTE speed is 38.4 Kbps in asynchronous mode. If the  
local DTE does not support this speed, change the modem’s DTE Speed  
option setting. In Hayes mode, the default DTE speed is automatically  
overridden when the Modem is autobauded (the Hayes mode AT attention  
code is sent to the Modem).  
4. HAYES MODE  
In Hayes mode with default settings in effect, the Modem transmits result  
codes (messages) to the DTE. In some instances, this may cause undesirable  
interaction with the attached DTE. If such interaction occurs, use the AT Q2  
command to suppress result codes for incoming calls.  
5. ALL LEASED-LINE MODES (2-WIRE, 4-WIRE, AND V.33)  
DTR (Data Terminal Ready) must be ON for the units to train on the leased  
line. (If DTR is ON, the TR indicator is present on the EIA status screen.)  
Four types of compromise equalization are available to compensate for  
distortion. If the signal quality appears to be inadequate (see Quality Screen  
in Section 7.6.2), or if the modems are frequently retraining, try changing  
the equalization option. See Compromise Equalizers in Section 3.3.6.  
6. LEASED-LINE (EXCLUDING V.33 OPERATION)  
Make sure one modem is set to originate mode and that the other is set to  
answer mode. (If the correct Quick Setup is selected, and not incorrectly  
modified, the answer/originate status should be correct.)  
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Modem 34336  
NOTE  
This page is intentionally left blank.  
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3.0 Modem Setup Options  
3.0 Modem Setup Options  
3.1 Methods For Selecting Options  
The Modem allows you to easily select options for tailoring the modem’s  
operation to suit a particular application. You can be select options in the  
following ways:  
Quick Setup — the easiest way to set up the Modem. Quick Setup  
(explained in Chapter 2) automatically sets all options according  
to a preset configuration.  
Front-panel selection — the easiest and most commonly used method for  
selecting individual options. You can select an overall configuration via  
Quick Setup, and then change selected options from the front panel to  
suit your application. To make changes, access individual option screens  
on the front panel LCD. Make selections using the control pushbuttons.  
• Summary Setup — the fastest way to selectively change options. All  
options are accessed using a few of the LCD screens. These screens show  
numerical codes with very little explanation. Therefore, Summary Setup  
is recommended for experienced users only. Summary Setup is explained  
in Appendix C.  
TRANSMITTER  
RECEIVER  
PATTERN  
GENERATOR  
PATTERN  
DETECTOR  
Figure 3-1. LCD Pushbuttons.  
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Modem 34336  
3.2 Selecting Options from the Front-Panel  
3.2.1 PUSHBUTTONS AND THE LCD  
Options are selected from the front panel by pressing the front panel  
pushbuttons (Figure 3-1). The possible choices for each option are shown  
on the liquid crystal display (LCD) and on the flow chart at the back of this  
manual.  
1. Arrow Pushbuttons. Use the left arrow and right arrow pushbuttons to  
display additional or previous pages (screens) of a menu. The right arrow  
pushbutton displays an additional menu page (if there is one); the left arrow  
pushbutton displays the previous page of a menu. With respect to how the  
LCD flow chart is set up, the arrow pushbuttons move you either right or  
left within the chart.  
If the menu has more than one screen, each screen is numbered. This  
number appears in the upper right corner of the LCD display. If there is no  
page number, the menu has only one screen. Additional pages of a menu  
show additional option selections. In the example below, the screen number  
(or page number) is 2.  
MAIN MENU <2>  
SETUP TEST RMT  
1
2
3
2. Numbered Pushbuttons. Pushbuttons 1, 2, and 3 correspond to segments  
1, 2, and 3 of the LCD screen. These segments (left, middle and right  
positions of the LCD screen) are numbered on the modem’s front panel.  
With respect to how the LCD flow chart is organized, pushbuttons 1, 2,  
and 3 either take you to a lower level or allow you to select an option  
when there is no route to a lower level.  
3. ENT Pushbutton. To exit from a displayed screen, press the ENT  
pushbutton. With respect to how the LCD flow chart is set up, pushing  
ENT moves you upward through the chart (toward the MAIN MENU).  
Pressing ENT repeatedly will return you to screen 1 of the MAIN MENU.  
Pressing ENT repeatedly after arriving at the MAIN MENU screen 1 causes  
the LCD to alternate between the EIA status screen and the MAIN MENU.  
In the case of most tests, ENT cannot be used to exit the test screen once  
the test is activated. To exit a test, first press ENT, and then select OFF  
to end the test.  
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3.0 Modem Setup Options  
NOTE  
If you have selected a Quick Setup or have changed certain options  
settings, pressing the ENT pushbutton to exit the SETUP menu will  
cause the modem to reset.  
3.2.2 HOW  
TO  
SELECT OPTIONS  
Options are configured from the SETUP menu.  
To access the SETUP menu, press the right-arrow pushbutton at  
page 1 of the MAIN MENU. This will take you to page 2 of the MAIN MENU.  
Press push button 1 to select SETUP.  
SETUP  
<1>  
TYPE LINE SPEED  
1
2
3
Front panel  
LCD  
The SETUP menu has six screens. Use the arrow pushbuttons until the  
option you wish to configure is displayed on the bottom line of the LCD  
window. Select the option you wish to configure by pressing the pushbutton  
that corresponds to the number on the front panel.  
When you select an option, the option flashes on the LCD. The option will  
not take effect until you leave the SETUP menu. Simply accessing an option  
screen does not change the option, so not hesitate to move through the  
various LCD screens in the SETUP menu.  
Note the following points:  
• Selected options do not become active until you leave the SETUP menu.  
• Changing some options causes the modem to automatically reset.  
• The options you select are automatically saved by the Modem when  
you leave the SETUP menu.  
1. DEC/INC (Decrease/Increase) Screens. Several option screens show  
the abbreviations DEC and INC on the bottom line of the LCD display. The  
abbreviations mean the numerical value shown on the top line (e.g., a stored  
phone number) can be changed. Selecting DEC (pushbutton 1) decreases  
the value; selecting INC (pushbutton 3) increases it.  
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Modem 34336  
2. Option-Selection Example. The following example illustrates option  
selection. As you follow the steps below, refer to the LCD flow chart (SETUP  
OPTIONS side) at the back of this manual. When you are finished, you can  
easily restore default settings for the type of application you are using by  
selecting the appropriate Quick Setup (see Section 2.3, Quick Setup).  
The example shows how to change the volume of the modem’s speaker from  
LOW or HIGH (the default setting) to MEDIUM. To make this adjustment,  
locate the SPEAKER VOLUME screen on the LCD. Access MAIN MENU  
screen 2, then SETUP screen 4. Finally, access MODEM SETUPS screen 5.  
The steps are explained in detail below.  
After powering on the modem, press ENT to get the first screen of the MAIN  
MENU. Press the right arrow pushbutton to go to screen 2 of the MAIN  
MENU, shown below.  
MAIN MENU <2>  
SETUP TEST RMT  
1
2
3
SETUP  
<1>  
Press pushbutton 1 to access the first  
page of the SETUP menu, shown right.  
TYPE LINE SPEED  
1
2
3
SETUP  
<4>  
Press the right arrow pushbutton  
three times to display SETUP screen 4,  
shown left.  
TEST EIA MODEM  
1
2
3
MODEM SETUPS <1>  
Press pushbutton 3 to select MODEM  
(for MODEM SETUPS). The first  
MODEM SETUPS screen is shown right.  
CDLVL  
TXLVL  
1
2
3
MODEM SETUPS <5>  
Press the right arrow pushbutton four  
times to reach MODEM SETUPS  
screen 5, shown left.  
FP SPK SPKVOL  
1
2
3
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3.0 Modem Setup Options  
Press pushbutton 3 to select SPKVOL  
(speaker volume). The SPEAKER  
VOLUME screen is shown right.  
SPEAKER  
VOLUME  
LOW MEDIUM HIGH  
1
2
3
The currently selected setting flashes. Press pushbutton 2 to switch the  
volume setting to MEDIUM. MEDIUM begins to flash, indicating the new  
selected setting (although the new selection does not become active until  
you exit the SETUP menu). To return to the first page of the MAIN MENU,  
press the ENT button several times.  
3. Returning to the EIA Status Screen. Once your selection is complete,  
return to the EIA status screen. Press the ENT pushbutton several times—  
the exact amount depends on which screen you are exiting from. (If the  
modem is in a test mode, press ENT and select OFF to end the test.)  
4. Automatic Configuration Save Feature. When you exit the SETUP menu,  
the Modem automatically saves its current configuration (i.e., option setups,  
including any changes you made) to its internal memory. The saved  
configuration remains in effect until it is changed (even if a loss of power  
occurs).  
5. How to Return to Default Settings. The factory default settings are  
different for each of the Quick Setup configurations available to the modem.  
To return to the factory default settings for any of these configurations, go to  
the QUICK SETUP menu and select the desired configuration.  
The 2-Wire Dial (Hayes) Quick Setup does not recall the factory-default  
settings, it recalls the stored user profile 0 or 1, depending on which is  
designated as the default (see &Y command in 5.0, Hayes Emulation Mode).  
To entirely reconfigure the modem to the state it was in when shipped from  
the factory, hold in the right arrow pushbutton as you power up the modem  
until the words FACTORY DEFAULT appear on the LCD.  
3.3 Options  
The rest of this chapter describes the options available from the Modem’s  
front panel. The options are presented in the same order in which they  
appear in the LCD flow chart at the back of this manual.  
The line below each option heading indicates the applicability of the option.  
A Quick Setup mode is listed only if the option is effective in that mode and  
if it can be of practical use in that mode.  
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Modem 34336  
The default settings for each option are listed in Appendix B.  
The Quick Setup options (one for each operating mode) affect the entire  
modem configuration. See Chapter 2.  
The Line Type options are available for all modes:  
2-WIRE DIAL — for dialup applications.  
2W-LL — for leased-line applications using 2-wire lines.  
4W-LL — for leased-line applications using 4-wire lines.  
The Speed Limit option (available for all modes) allows you to set a minimum  
and/or maximum data rate. The Modem automatically operates at the  
highest possible data rate within the limits selected, as indicated in Table 3-1.  
Only the minimum rate selection applies to Hayes mode operation.  
EIA-23 is available for setting the maximum rate only. If EIA-23 is selected,  
the rate is set at either 9600 or 4800 bps, depending on the condition of  
pin 23 on the EIA interface:  
• Pin 23 high (greater than or equal to +3 volts) = 9600 bps.  
• Pin 23 low (less than or equal to -3 volts) = 4800 bps.  
Use the Speed Matching option if you don’t want speed conversion. You can  
set the DTE interface rate to follow the rate at which the modem connected  
(i.e., DTE=DCE).  
NOTE  
Speed matching is only effective for dial applications and will  
only function if V.42 error correction and/or buffer mode is enabled.  
To select speed matching, refer to Appendix C. Follow the instructions given  
there to change the value identified in the MISCELLANEOUS OPTIONS  
diagram as the DTE=DCE speed parameter from 0 (the factory setting) to 1.  
The Speed Limit Type screen is only present on the Modem . The V.32  
master handshake normally used by the Modem is incompatible with the  
CCITT V.33 and Bell 208 handshakes. However, the Modem can be  
configured for either V.33 or Bell 208 compatibility.  
V.33 or Bell 208 speed limits can be set independently of other options via  
the Speed Limit Type screen. However, to ensure proper operation, it is  
recommended that you use the V.33 or 208 Quick Setup configuration,  
as explained in Chapter 2.  
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3.0 Modem Setup Options  
Table 3-1. Effect of Speed Limit Settings on Data Rate  
MAX RATE  
SETTING, bps  
DIALER  
OPTION  
RESULTANT DATA RATE, bps  
LEASED LINE MODES  
14,4001  
12,0001  
xx  
xx  
xx  
xx  
xx  
14,4001  
12,0001  
9600  
9600  
300 to 4800  
EIA-CTRL  
4800  
9600 or 48002  
DIAL MODES—ANSWERING  
300 to 14,4001  
EIA-CTRL  
xx  
xx  
Negotiated between minimum and  
maximum setting  
9600 or 48002  
DIAL MODES—ORIGINATING  
300 to 14,4001  
OFF  
Negotiated between minimum and  
maximum setting  
EIA-CTRL  
xx  
OFF  
HAYES3  
9600 or 48002  
Negotiated between autobaud  
speed and 300 bps3  
xx Does not matter—condition does not affect resultant data rate.  
1
14,400 and 12,000 bps rates are for the Modem only.  
2
9600 bps if EIA pin 23 is high, 4800 bps if pin 23 is low.  
3
If SYNC AFTER DIAL is enabled (using the &Q1 command), the  
rate is negotiated between the autobaud speed and 1200 bps.  
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Modem 34336  
V.32. The Modem normally uses the V.32 handshake. (The Modem also  
uses this handshake for V.32/14,400 bps operation.)  
• V.33. V.33 operation is available on the Modem for 4-wire leased line  
synchronous operation only. The available data rates are 14,400 and  
12,000 bps. Either of these rates may be set as the maximum or minimum  
by using the Speed Limit MAXIMUM RATE and MINIMUM RATE  
screens. Both connected modems must be set for V.33 leased-line  
operation.  
• V.34. V.34 extended (33.6 kps) mode of operation is in compliance  
with proposed TR-30.1 implementation of two new data rates (31.2kps  
and 33.6kps) which are compatible with V.34 recommendation.  
Interoperability with modems is ensured, provided they comply  
with the TR30.1 proposal.  
208. This selection (on the Modem only) provides both Bell 208A  
compatibility for 2-wire or 4-wire leased line operation and Bell 208B  
compatibility for 2-wire dial operation. Operation is full duplex in 4-wire  
leased line mode only. In Bell 208B mode, synchronous V.25 bis  
autodialing is available, but Hayes operation is not. In Dumb mode, calls  
may be originated from the front panel. The data rate is fixed at 4800 bps  
for 208A/B operation, and the data format is synchronous only. Both  
connected modems must be set for 208A/B operation. For 2-wire  
applications, the carrier option must be set for switched carrier operation  
(SWITCH) via the CARRIER screen, and CTS must be set to follow RTS  
(CTS to EIA option).  
Three options intended only for 208A/B and V.33 operation are accessible  
through MODEM SETUPS screen 7. These options allow you to select  
constant or switched carrier, set CTS to follow RTS or set CTS to be always on,  
or specify an RTS-CTS delay time. For further information, see the CARRIER,  
CTS, and RTS-CTS DELAY headings later in this chapter.  
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3.0 Modem Setup Options  
3.3.1 V.42 ERROR CORRECTION OPTIONS  
The Modem supports both CCITT V.42 error correction and Microcom  
®
®
Networking Protocol (MNP ) error correction (classes 1 through 5).  
V.42 and MNP provide end-to-end error correction through an automatic  
repeat-transmission request algorithm. Both types of error correction  
enable the Modem to detect data transmission errors and automatically  
request retransmission of adversely affected data until it is received correctly.  
Either error-correction standard (V.42 or MNP) may be enabled for dial  
or leased-line operation. However, error correction can function only if  
all of the following conditions are present:  
• The modem that the Modem is communicating with must be equipped  
with the same type of error correction (V.42/V.42 bis or MNP).  
• The same type of error correction (V.42/V.42 bis or MNP) must be  
enabled at both ends of the communication link.  
• Both communicating modems must be configured for asynchronous  
data format.  
• The connected systems must support data flow control (have buffering  
capabilities).  
The V.42 and MNP error-correction options (listed and described below)  
are effective only when all of the conditions listed above are present.  
Error correction options cannot be changed when the modem is on-line.  
For valid test results, disable error correction before running diagnostic tests.  
User-selectable options allow you to configure the Modem for V.42 (LAPM)  
error correction only, MNP error correction only, or V.42 error correction  
with MNP as the fallback error correction protocol. Data compression may  
also be enabled by selecting either V.42 bis or MNP class 5 error correction.  
Other error-correction options are also available.  
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Modem 34336  
The available error correction options are listed below:  
• V.42 Mode  
• DTE Speed  
• MNP Class (class limit)  
• Break Handling  
• DTE-DCE and DCE-DTE Flow  
Control options  
• V.42 Selection  
• Flyback Buffer  
• Buffer Mode/Speed Conversion  
• Pass-Through Flow Control  
All of the above options affect the type of error correction selected via the  
V42 SELECTION screen (discussed below), except that the MNP Class and  
Flyback Buffer options are applicable only to MNP operation.  
The error-correction options can be selected in any order, but the following  
sequence is suggested:  
1. Select the type of error correction desired from the V42 SELECTION screen.  
2. Make a selection from the V.42 Mode screen.  
3. Select other error-correction options as appropriate for your application.  
The V.42 Mode is available for Hayes, V.25 bis, Dumb, and Leased-Line  
modes (except V.33).  
The V.42 Mode settings described below apply to the type of error correction  
selected with the V42 Selection screen. For example, if LAPM ONLY is  
selected as the error correction protocol, and MANDATORY is selected  
from the V42 Mode screen, V.42 or V.42 bis error correction is activated.  
If the error correction cannot be activated, the Modem will hang up.  
• OFF — Error correction will be disabled.  
• MANDATORY — Error correction will be activated. If the modem cannot  
establish a connection using the type of error correction selected via the  
V.42 Selection option, it will hang up.  
• AUTO — The Modem will fall back to buffer or non-buffer mode if  
conditions do not allow it to establish a connection using the type  
of error correction selected via the V42 SELECTION screen.  
The MNP Class (Limit) is available for Hayes, V.25 bis, Dumb, Leased Line  
modes (except V.33). This option is effective only when MNP error correction  
is active. It limits MNP operation to the selected MNP class or lower (MNP  
classes 1-5 are available). In general, the higher MNP classes provide the most  
throughput efficiency. Class 5, the default, can provide as much as 2-to-1 data  
compression over the transmission link.  
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3.0 Modem Setup Options  
The following two options are available through the V42 SELECTION screen:  
The Protocol option is available for Hayes, V.25 bis, Dumb, and Leased-Line  
modes (except V.33).  
LAPM/MNP — The Modem attempts to establish a connection using  
the V.42 link access protocol (LAPM/MNP). This is the primary error  
correction protocol under the CCITT V.42 standard. If such a connection  
cannot be established (because the other modem does not support LAPM  
or is not configured for LAPM), the Modem attempts to establish a  
connection using MNP Class 5 as the fallback error correction protocol.  
NOTE  
When operating in LAPM mode, the Modem uses V.42 error correction  
unless V.42 bis is enabled via the V.42 bis option. (V.42 and V.42 bis  
error-correction both use LAPM.)  
• LAPM ONLY — The modem only attempts to establish an LAPM  
connection (will use only V.42 or V.42 bis error correction).  
• MNP ONLY — The modem will only attempt to establish an MNP connection.  
NOTE  
If a connection cannot be established using the selected protocol (LAPM/  
MNP, LAPM ONLY or MNP ONLY), the action the Modem takes depends  
on the V.42 mode setting.  
V.42 bis Operation is available for Hayes, V.25 bis, Dumb, and Leased-Line  
modes (except V.33). V.42 bis operation provides error correction with  
data compression. Like V.42 error correction, V.42 bis uses the link access  
protocol (LAPM). V.42 bis operation may be enabled or disabled.  
The Break Handling option is available for Hayes, V.25 bis (Async only),  
Dumb, Leased line modes (except V.33). When error correction is active,  
a break signal is relayed with an attention packet. The break-handling  
option determines how the attention packet is sent.  
• NONE — No attention packet is sent.  
• DESTRUCTIVE/EXPEDITED (DESTR/EXP) — All data in the buffer  
is deleted; the attention packet is then passed through the channel.  
• NON-DESTRUCTIVE/ EXPEDITED (NDT/EXP) —The attention packet  
is passed through immediately, but data in the buffer is not deleted.  
• NON-DESTRUCTIVE/NON-EXPEDITED (NDT/NEXP) — The  
attention packet is passed through the channel in sequence, and any  
data is buffered; this preserves the sequence of data and breaks received.  
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Modem 34336  
The Buffer Mode/Speed Conversion option Hayes, V.25 bis, Dumb, Leased  
line modes (except V.33). It enables or disables speed conversion (for  
asynchronous operation only) between the DTE and modem when error  
correction is not used.  
• ENABLE — When error correction is not enabled, the V.42 circuit  
functions as a buffer between the DTE and the modem and provides  
transmission speed conversion.  
• DISABLE — Speed conversion is not allowed.  
The DTE Speed option is available for Hayes, V.25 bis, Dumb, Leased-Line  
modes (except V.33). It controls the DTE speed; however, it is effective only  
when the modem is operating in V.42 mode, MNP mode, or buffer mode.  
The DTE speed can be set for 115,200, 57,600, 38,400, 19,200, 9600, 4800,  
2400, 1200, 600, 300, or 110 bps. The default "DTE speed" is 38,400 bps.  
DTE speed refers to the speed of data transfer between the DTE and the local  
modem. It is not necessarily the same as the data transmission speed between  
the connected modems. If flow control is disabled, the DTE speed must be  
equal to or less than the modem speed, and the local and remote DTE speeds  
must be equal.  
For Hayes mode operation, the DTE Speed option sets the default DTE speed  
that will be effective after powerup or after a full modem reset. However, the  
default DTE speed is automatically overridden when the Modem is  
autobauded (when an AT attention code is sent to the Modem).  
The Flow Control options control the data flow according to the availability  
of memory space in the V.42 buffer. Flow control can be set independently  
for the modem to the terminal and for the terminal to the modem. The  
flow-control options include DTE-DCE, DCE-DTE and Pass-Through Flow  
Control, and Flyback Buffer.  
NOTE  
When flow control is disabled, the DTE data rate must be equal to or less  
than the modem data rate, and the local and remote DTE data rates must  
be equal. (This precludes the need for flow control, which some  
computers and terminals cannot handle, and avoids buffer overflow.)  
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3.0 Modem Setup Options  
The DTE-DCE Flow Control options are available for Hayes, V.25 bis, Dumb,  
and Leased-Line modes (except V.33).  
• NONE — No flow control is used.  
• RTS ON/OFF — The Request to Send signal controls  
data flow from the modem to the terminal.  
• DC1/DC2 — Inserts control characters (CONTROL-R and CONTROL-Q)  
in the data stream stop and start the flow of data from a device.  
• DC1/DC3 (X-ON/X-OFF) — The most common method of flow control.  
It inserts control characters into the data stream: CONTROL-S stops the  
flow of data, and a CONTROL-Q restarts it.  
NOTE  
When using the modem for binary file transfer, in-band flow control (flow  
control using control characters) must be disabled. In this case, use  
hardware flow control or, as an alternative, lower the DTE speed to  
lessen the possibility of overflow.  
The DCE-DTE Flow Control options are available for Hayes, V.25 bis, Dumb,  
and Leased-Line modes (except V.33). All information given above under  
DTE-DCE Flow Control options also applies to DCE-DTE (modem to  
terminal) flow control options, except that the CTS, Clear to Send,  
signal is used to control DTE-DCE data flow instead of RTS.  
Flyback Buffer options are available Hayes, V.25 bis, Dumb, Leased line  
modes (except V.33). The Flyback Buffer option is effective only when MNP  
error correction is active. Flyback buffering is used for specific applications  
such as printers, teletypes, etc.  
• ENABLE — If MNP is buffering data, a five-character delay is inserted  
after the following characters are sent to the terminal: HT (09), LF (0A),  
VT (0B), FF (0C), and CR (0D).  
• DISABLE — Flyback buffering will not occur.  
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Modem 34336  
The Pass-Through Flow Control options are available for Hayes, V.25 bis, Dumb,  
and Leased-Line modes (except V.33). Pass-Through Flow Control affects DTE-  
DCE flow control only. This option determines whether flow control characters  
are passed through the communication channel (but only if control characters  
are used for flow control).  
• ENABLE — Flow-control characters are passed to the remote end  
of the communication connection after the modem acts upon them.  
• DISABLE — Flow-control characters are not passed.  
The Address option is available for all modes. The address screen allows you  
to set the address of the modem at your location. An address may be useful  
if the Modem will be used in a rack enclosure or in a network environment.  
The available address numbers are 000,000 through 999,999. On the Address  
screen, the three digits to the right of the comma are the unit address  
number. The three digits to the left are the group address number. To  
change the address, use the right and left arrow pushbuttons to go to the digit  
you want to change. Then use pushbutton 1 to decrease (DEC) a number and  
pushbutton 3 to increase (INC) it. The default address is 999,999.  
3.3.2 DIALER MODE  
Several Dialer Mode options can be selected from the DIALER and DIAL  
V25bis screens.  
The Dialer Options are available for all modes.  
• OFF — The autodialer is off, meaning the modem operates in Dumb  
mode only. Calls must be made using the front panel AUTO-DIAL  
function or they must be manually originated.  
• HAYES — The autodialer automatically dials previously stored phone  
numbers, and the modem responds to Hayes commands.  
• DTR — This selection enables DTR dialing, an option that allows you to  
set up the Modem to automatically dial a stored number even when the  
autodialer is not enabled. (For further information, see Section 4.5).  
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3.0 Modem Setup Options  
The V.25 bis Dialer Modes are available for V.25 bis mode.  
Any of the selections from the DIAL V25bis screen will enable the V.25 bis  
autodialer. For detailed information on the V.25 bis autodialer, see Chapter 6.  
The three selections on the DIAL V25bis screen allow you to select a data  
protocol that is appropriate for the DTE the Modem is connected to:  
• ASYNCHRONOUS (Asyn)  
• SYNCHRONOUS, CHARACTER ORIENTED (Syn_c)  
• SYNCHRONOUS, BIT ORIENTED (Syn_b)  
NOTE  
DTR dialing for V.25 bis mode cannot be enabled through the DIALER  
screen. To select DTR dialing for V.25 bis mode, you must use the  
Summary Setup feature, as explained in Chapter 6.  
The Auto-Answer option is available for Hayes, V.25 bis, and Dumb modes. It  
determines whether or not a call is automatically answered when the phone  
rings. Setting the Auto-Answer option to ENABLE resets Hayes mode register  
S0 to 1 (meaning that calls are answered on the first ring).  
3.3.3 DATA FORMAT OPTIONS  
The Data Format (Sync or Async) option is available for V.25 bis, Dumb, and  
Leased-Line modes. The data format setting for the local modem and for the  
remote modem must be the same.  
• ASYNCHRONOUS — Data is transmitted and received in the character  
asynchronous format. The character length (next option) must be the  
same for both communicating modems.  
• SYNCHRONOUS — If this option is selected, data must be transmitted  
and received in the synchronous format. The appropriate transmitter  
clocking option must be selected. The synchronous data format is not  
available for data rates of 300, 19,200, or 38,400 bps.  
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Modem 34336  
The Character Length option is available for all modes (asynchronous  
operation only). It selects a character length of 8, 9, 10, or 11 bits for  
character asynchronous operation. The same character length must be  
selected for both the local and the remote modems. Use pushbuttons  
1 and 3 to select the desired character length.  
8 BITS: 1 start bit, 6 data bits and 1 or more stop bits.  
9 BITS: 1 start bit, 7 data bits and 1 or more stop bits.  
• 10 BITS: 1 start bit, 8 data bits, including parity, and 1 or more stop bits.  
• 11 BITS: 1 start bit, 9 data bits, including parity, and 1 or more stop bits.  
In Hayes mode, character length is set automatically under most conditions.  
The Parity option is available for all modes. Parity selections are effective  
only if error correction or buffer mode has been enabled or if the Modem  
is in 2-Wire Dial (Hayes) mode. For most applications, parity should be set  
to NONE.  
The following parity options are available: NONE (no parity), ODD, EVEN,  
MARK (parity is always 1) and SPACE (parity is always 0). All parity settings  
except NONE automatically enable parity conversion (except in Hayes  
mode), meaning that the parity of received data is converted to match the  
selected parity option.  
In Hayes mode, parity is set automatically under most conditions.  
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3.0 Modem Setup Options  
3.3.4 DISCONNECT OPTIONS  
When the modem is operating in V.25 bis or Dumb mode, it is necessary to  
disconnect the modem from the telephone circuit once communications are  
completed. The most common form of disconnection is by dropping the Data  
Terminal Ready (DTR) signal from the DTE. However, some applications may  
require one of the five available automatic disconnect methods listed below.  
For all five disconnect options, "disabled" means the modem will not  
disconnect in the presence of the conditions specified below.  
The RX (Receive) Space Disconnect option is available for Hayes, V.25 bis,  
and Dumb modes. If it is enabled, a 1.6-second continuous space will cause  
the modem to disconnect.  
NOTE  
For Hayes mode operation, both the RX Space Disconnect and TX Space  
Disconnect options must be either enabled or disabled.  
The TX (Transmit) Space Disconnect option is available for Hayes, V.25 bis,  
Dumb modes. When TX Space Disconnect is enabled, the Modem transmits  
4 seconds of space prior to disconnecting from the line. This ensures a clean  
disconnect if RX space disconnect is enabled on the remote modem.  
NOTE  
For Hayes mode operation, both the TX Space Disconnect and RX Space  
Disconnect options must be either enabled or disabled.  
The Character Disconnect option is available for V.25 bis, and Dumb modes.  
If it is enabled, a 400-ms loss of carrier signal causes the line to be  
disconnected. (To set this option for Hayes mode, use S register S10 --  
see Section 5.3.)  
The Line Current Disconnect option is available for V.25 bis, Dumb modes.  
If enabled, a 400-ms loss of current causes the line to be disconnected.  
(To set this option for Hayes mode, use S register S10 -- see Section 5.3.).)  
The RTS Disconnect option is available for Hayes, V.25 bis, and Dumb modes.  
When RTS Disconnect is enabled, if RTS is off for a selected period  
of time (20 to 140 seconds, user selectable), the line is disconnected.  
Use pushbuttons 1 and 3 to set the RTS-OFF period required for a  
disconnect.  
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Modem 34336  
3.3.5 TEST OPTIONS  
The Test Options affect certain tests (as explained below) but do not activate  
tests.  
The DSR During Analog Loopback is available for all modes. When ON  
is selected, the Data Set Ready signal is forced on when the modem is in  
the analog loopback test mode. In general, this option should be left ON  
(the default selection).  
The Remote Test option is available for all modes. The Remote Test option  
allows you to prevent tests from being initiated on the local Modem from a  
remote modem. If DISABLE is selected from the Remote Test screen, the  
local Modem ignores test initiation signals from a remote modem. If ENABLE  
is selected, tests can be initiated from a remote modem.  
Note that there are two REMOTE TEST screens. One is for the option just  
described; the other is used for selecting either the remote digital loopback  
tests or remote front panel control. The Remote Test option screen (for  
preventing or allowing remote testing) looks like the one shown below.  
REMOTE TEST  
ENABLE DISABLE  
1
2
3
3.3.6 EIA OPTIONS  
The seven options described below allow control over specific EIA interface  
signals.  
The CTS to EIA options are available for all modes. Regardless of the setting  
selected for this option, Clear to Send (CTS) is off during flow control (which  
occurs if error correction and flow control or buffer mode are enabled).  
• NORMAL — The Clear to Send signal is on while the modem is on-line.  
• RTS — The CTS signal immediately follows the RTS signal with no delay.  
• TRUE — The CTS signal follows DTR.  
CTS can also be set to be ON at all times regardless of DTR by using the  
Summary Setup feature. However, if CTS on/off is selected from DCE-DTE  
screen 1, V.42 flow control, while active, overrides the CTS ON selection.  
To set CTS ON, refer to Appendix C. Note that if you set CTS to ON using  
Summary Setup and then make a selection from the CTS to EIA screen,  
that selection cancels the Summary Setup CTS ON selection.  
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3.0 Modem Setup Options  
NOTE  
The Modem also supports a CTS option intended only for V.33  
and Bell 208A/B operation, described later in this chapter.  
The CD to EIA option is available for Hayes, V.25 bis, and Dumb modes.  
• NORMAL — Carrier Detect (CD) is on while the modem is on-line.  
• TRUE — CD follows DTR supplied from the DTE.  
• TOGGLE — CD turns on whenever DTR is present and then toggles  
off for 500 ms upon disconnect, allowing the attached DTE to  
recognize that the call is ended and the connection is dropped.  
The DSR to EIA option is available for Hayes, V.25 bis, and Dumb modes.  
• NORMAL — Data Set Ready (DSR) is on while the modem is on-line.  
• TRUE — DSR follows DTR supplied from the DTE.  
• CROSSOVER (XOVER) — DSR is ON without DTR and toggles for  
500 ms upon local or remote disconnect.  
The DTR from EIA is available for all modes. It allows you to force the Data  
Terminal Ready (DTR) signal on (TRUE), which may be needed if your  
computer or communication software does not supply a DTR signal.  
• NORMAL — DTR is supplied by the DTE.  
• TRUE — The DTR signal is internally forced ON regardless of the DTR  
status at the interface.  
The DTE Control Of ALB (ALB- DTE Ctrl’ed) option is available for all  
modes. Analog loopback (ALB) testing can be initiated from the DTE via  
pin 18. Positive voltage activates the test, whereas negative voltage results in  
normal operation. Disabling this option keeps the modem from responding  
to pin 18.  
The DTE Control Of RDL (RDL- DTE Ctrl’ed) option is available for all  
modes. Remote digital loopback (RDL) can be initiated from the DTE via  
pin 21. Positive voltage activates the test, whereas negative voltage results in  
normal operation. Disabling this option keeps the modem from responding  
to pin 21.  
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Modem 34336  
The Test Mode (TM to EIA) option is available for all modes. It controls  
pin 25, the test mode (TM) indicator, on the RS-232 interface connector.  
• NORMAL — TM output is high (active) only during test modes.  
• TRUE — TM output is high all of the time.  
3.3.7 MODEM SETUPS  
The options listed below, through RTS-CTS DELAY, are available through  
the MODEM SETUPS screens.  
The Carrier Detect option is available for all modes. It selects the carrier  
detect level. To make a selection, first select either LEASED or DIAL from the  
CARRIER DET. LVL screen, depending on your application. The appropriate  
carrier detect level screen is displayed.  
• For leased-line use — the carrier detect level can be set for 43, 33 or 26  
dBm. The default setting is 26 dBm.  
• For dial-line use — the carrier detect level can be set for 51, 41, or 34  
dBm. The default setting is 51 dBm.  
The Transmit Level option is available for all modes. It controls the modem’s  
transmission level. To make a selection, first select either LEASED or DIAL  
from the TRANSMIT LEVEL screen.  
• For leased lines — the transmission level can be set between 0 and -15  
dBm, in 1-dBm steps. The standard setting is 0 dBm. (Use pushbuttons 1  
and 3 to select the desired transmission level.)  
• For dialup applications — the transmission level for dial lines can be set as  
either programmable, if you are using RJ-45S connectors, or permissive,  
fixed at -10 dBm +/-1 dBm, which is the most common setting.  
The Signal Quality option is available for all modes. It sets the threshold for  
the ER (error) indication during normal operation. You can choose either  
"10 3", one error in 1000 bits, or "10 5", one error in 100,000 bits. Signal  
quality (along with carrier detect) also controls the threshold the modem uses  
as a criterion for entering the Leased Line Auto-Recovery mode.  
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3.0 Modem Setup Options  
The Compromise Equalizers option is available for all modes.  
NOTE  
The compromise equalizers affect only V.32 operation (4800 to 14,400  
bps, asynchronous/synchronous, full duplex).  
For most applications, the automatic adaptive equalizer setting provides all  
the equalization necessary to compensate for line impairments, meaning that  
equalizer adjustments are generally not necessary. However, in the event that  
equalizer adjustment is needed, any of four types of compromise equalization  
can be selected: Type I (T-I on the LCD), Type II (T-II), Type III (T-III) and  
Type IV (T-IV). The equalizer can also be turned OFF.  
Where line conditions are atypical, it may be necessary to adjust the equalizers  
to optimize the signal quality. If adjustment is necessary, refer to the quality  
screen for guidance; this screen shows a relative indication of the signal  
quality, in both numeric and graphic form.  
The Trellis Code option is available for all modes. Trellis coding provides  
performance advantages for all modulation patterns. The modem’s CCITT  
compliant trellis coder is normally enabled at speeds of 9600 bps and above,  
but may be negotiated off by a modem that is not equipped with a trellis  
coder. The trellis code option allows you to enable or disable the trellis coder.  
The Transmitter Clocking option is available for all modes. It selects one of  
three possible sources for the transmitter timing signal:  
INTERNAL — The timing of the modem and data terminal transmitting  
circuits is provided by an internal clock within the modem.  
• RECEIVED (RX-CLK) — The timing of the received data is used to  
control the timing of the data transmitted. This timing mode is used if the  
modem’s transmit timing must be controlled by a remote source.  
• EXTERNAL — The timing of the modem and data terminal transmitting  
circuits is provided by an external clock within the data terminal and is  
provided to the modem via the DTE connector pin 24. This mode of  
clocking is used if the DTE must be in control of the modem’s transmit  
timing.  
The T1 Timer option is available for Hayes, V.25 bis, and Dumb modes. It  
determines how long the Modem attempts to handshake with a calling V.32  
modem before falling back to a lower speed. The available T1 Timer settings  
are 0, 0.3, 0.8, 1.6 and 3.0 seconds.  
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Modem 34336  
Normally, as part of the V.32 handshake, the calling modem begins sending  
a sequence to the answer modem while the answer modem is still sending  
answer tone. In this case, there is no T1 timer. However, the V.32  
recommendation allows for a T1 time of up to 3 seconds, meaning that the  
answer modem may be set to wait (before falling back) for up to 3 seconds.  
The B option is available for all modes. If the Modem makes a connection at  
one of the V.32 rates (4800 to 14,400 bps) or V.22 bis rate (2400 bps), it can  
request that the remote modem send a retrain sequence.  
• ENABLE — The modem requests a retrain sequence.  
• DISABLE The modem will not request a retrain sequence.  
The Answer/Originate Default option is available for Hayes and Leased  
modes (and manual originate/answer dial operation). It sets the Modem to  
default to either answer or originate status.  
• ANSWER — Sets the Modem to answer mode.  
• ORIGINATE — Sets the Modem is set to originate mode.  
The Answer Tone option is available for Hayes, V.25 bis, and Dumb modes.  
The answer-tone frequency is selectable only if the maximum data rate is set  
to 1200 bps (via the SPEED LIMIT menu), in which case the answer tone can  
be set to either 2225 or 2100 Hz. Otherwise, the answer tone frequency is  
2100 Hz (the standard for V.32 operation). In general, this setting should  
not be changed (even for fallback with Bell standard modems, which use a  
2225-Hz answer tone).  
The Front Panel Control option is available for all modes. It controls the use  
of the front panel. If disabled, the front panel of the modem will not respond  
to changes to the Setup menus. Front Panel Control is a security feature  
helpful in situations where it is undesirable for the modem’s configuration  
to be changed.  
Two speaker options are available: Speaker Control and Speaker Volume.  
The Speaker Control option is available for all modes.  
• ON — Speaker is on during the full modem handshake process and while  
the unit remains on-line.  
• OFF — The speaker is off; the call cannot be audibly monitored.  
• ON TILL CD — Speaker remains on until a carrier signal (CD)  
is detected.  
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3.0 Modem Setup Options  
The Speaker Volume option is available for all modes. It can be set to LOW,  
MEDIUM, or HIGH.  
The Guard Tones option is available for Hayes, V.25 bis, Dumb modes.  
Guard tones are used in V.22 and V.22 bis modes only, to assure proper band  
separation on systems that use international telephone circuits. Unless you  
are using international circuits in one of these modes, you should turn the  
guard-tone option OFF. If guard tones are required, their frequency can be  
set to 550 Hz or 1800 Hz (the most commonly used guard-tone frequency).  
V.13 Operation is available for V.25 bis, Dumb, and Leased modes  
(synchronous operation only).  
OFF — V.13 operation is off. This setting allows normal full duplex  
operation. (All other selections are for enabling V.13 operation.)  
TX ONLY — Status of RTS will be sent to remote modem.  
RX ONLY — Carrier Detect (CD) will be controlled by V.13 signals from  
the remote modem.  
TX AND RX — Status of RTS will be sent to remote modem, and CD will  
be controlled by V.13 signals from the remote modem.  
To select one of the four V.13 options, press pushbutton 1 or 3 with the V13  
screen displayed until the selection you want is displayed. For half-duplex  
point-to-point applications, select TX AND RX. For multidrop applications,  
select RX ONLY for all modems at the host site and TX ONLY for all  
modems at the remote site. For further information on V.13 operation,  
see Section 4.10.  
3.3.8 V.33 AND BELL 208A/B OPTIONS  
The following three options are available on the Modem only and are  
intended only for V.33 or Bell 208A/B operation. (For Bell 208 operation,  
see also the Satellite Delay and Turnaround Delay options.)  
The Carrier Type option is available for V.25 bis, Dumb, Leased line modes.  
• SWITCHED (SWITCH) — For 2-wire applications, the carrier type option  
must be set for switched carrier operation.  
• CONSTANT — Constant or continuous carrier can only be used for 4-wire  
leased-line applications (although such applications may also use switched  
carrier).  
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Modem 34336  
The CTS option is available for 4-wire Leased Line modes. It applies only  
to 4-wire leased line applications using constant carrier.  
RTS — The CTS signal follows RTS.  
• ON — CTS is always ON.  
NOTE  
The Modem also supports a CTS to EIA option, which is described earlier  
in this chapter under EIA OPTIONS.  
The RTS-CTS Delay (CTS Delay) option is available for V.25 bis, Dumb,  
Leased line modes. The available RTS-to-CTS delay settings are 0, 15, 50,  
or 150 ms. However, the only available choices for 208A/B operation are  
50 and 150 ms. If you select 0 or 15 ms, the actual delay in 208A/B mode  
will be 50 ms.  
NOTE  
RTS-to-CTS delay is not effective if the CTS option is set to ON (always  
ON). For V.33 operation, RTS-to-CTS delay is effective only for 4-wire  
leased line applications that use constant carrier.  
The PHONE screen for storing a telephone number and Auto-Recovery  
are discussed in Sections 4.2 amd 4.3.  
The LCD Intensity option is available for all modes. It allows you to  
use pushbutton 3 (for INC or increase) to darken characters on the  
LCD or pushbutton 1 (for DEC or decrease) to lighten them.  
3.3.9 OPTIONS ACCESSIBLE WITH SUMMARY SETUP ONLY  
The twelve options described below can only be changed through the  
modem’s Summary Setup feature, which is explained in Appendix C.  
The Wait For Carrier option is available for V.25 bis, Dumb modes. The time  
the modem waits for a carrier signal when origin-ating a call can be set for 30,  
45, 60, or 75 seconds. (In Hayes mode, the wait-for-carrier time is determined  
by the value in register S7.)  
The Phase Reversal in Answer Tone option is available for all modes. When  
enabled, the Phase Reversal in Answer Tone option signals the telephone  
network to turn off its echo cancelers. For virtually all applications, phase  
reversal should be enabled (the default setting).  
The Satellite Delay option is available for 208 mode. It facilitates transmission  
over satellite links (but does not permit fast-turnaround operation). When the  
Satellite Delay option is on, RTS is inhibited for 275 ms after the answer tone  
stops and after the DSR signal comes on. The delay occurs at both the  
originating and answering modems, allowing the echo suppressors on the  
telephone link to be enabled.  
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3.0 Modem Setup Options  
The Turnaround Delay option is available for 208 mode. It is intended for  
circuits where echo is a problem. It prevents the Modem from receiving an  
echo of its own transmitted data. When the Turnaround Delay option is on,  
CD (pin 8) is held low for 150 ms after RTS is turned off. If the modem  
detects an energy loss during the delay, it turns CD on 52 ms after detecting  
the loss. If the modem does not detect an energy loss, it turns CD on 52 ms  
after the end of the delay. The modem ignores any energy loss during the  
first 8.5 ms.  
The Analog Loopback Make Busy is available for all modes. If the Analog  
Loopback Make Busy option is enabled, the Modem provides a busy  
indication to the dial line interface when the Modem is in analog loopback  
test mode.  
The Selective Retransmission option is for Hayes,V.25 bis, Dumb, and Leased-  
Line modes (except V.33). This option allows the Modem to communicate  
with certain modems that are not able to respond to the MNP selective  
retransmission command.  
Enable — This setting allows the modem to request retransmission  
of a single information frame (in the event of a transmission error).  
Disable — Data can only be retransmitted in a series of information frames.  
The DCE Pass-Through Flow Control option is for Hayes,V.25 bis, Dumb,  
and Leased-Line modes (except V.33)  
This option affects DCE–DTE flow control only. It is only effective if error  
correction or buffer mode/speed conversion is ‘enabled’.  
Enable — The Modem will pass flow control characters received from  
the remote modem to the local DTE.  
Disable — The Modem will not pass flow control characters from the  
remote modem to the local DTE.  
The Link Flow Control option is for Hayes,V.25 bis, Dumb, Leased-Line  
modes (except V.33)  
This option is effective only if buffer mode/speed conversion is enabled  
and an error-correction link is not established.  
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Modem 34336  
Enable — The Modem will check for X-ON/X-OFF (DC1/DC3)  
flow control characters received from the remote modem to determine  
whether to stop or start/restart data transmission to the remote modem.  
A DC3 (or DC2) control character will cause the Modem/Modem 3242–S  
to stop data transmission and hold data in its buffer until it receives a DC1  
control character (which instructs the modem to resume transmission).  
Disable — The Modem will ignore X-ON/X-OFF (DC1/DC3)  
flow control characters received from the remote modem.  
Slaved — Link flow control is controlled by the DCE-DTE Flow Control  
option. If DCE-DTE Flow Control is set to NONE or CTS, Link Flow  
Control is disabled. Otherwise, it is enabled.  
The V.32 Mode option Hayes, V.25 bis, Dumb, and Leased-Line modes  
(except V.33)  
This option is used to select CCITT V.32 bis operation or V.32 extended  
operation.  
When V.32 bis mode is selected (factory-default setting), the follow-ing are  
available: RRP (Rate Renegotiation Procedure); data rate of 7200 bps; RATE  
screen that allows you to manually initiate RRP. RRP enables the modem to  
auto-matically fall back or fall forward to a lower or higher data rate during  
data transmission in response to changes in signal quality. Selecting V.32 bis  
mode makes RRP available as an option; however, RRP will not function unless  
it is enabled (the default setting is enabled.)  
When V.32 bis mode is selected, a RATE screen is available from MAIN  
MENU screen 3. The RATE screen can be used to manually initiate RRP  
for diagnostic purposes. For additional informa-tion, see Section 7.6,  
Diagnostic Monitoring: Status Screens.  
When V.32 bis mode is selected, 7200 bps can be selected as the maximum  
or minimum data rate (using the Speed Limit option). When V.32 bis is not  
selected, 7200 bps operation is not available.  
NOTE  
By definition, V.32 bis operation includes the ability to operate at 12,000 and 14,400  
bps. Therefore, only the Modem is a true V.32 bis modem. However, when the  
V.32 bis mode is selected on the Modem 32192, it will support the following  
options as well: RRP; 7200 bps data rate; the RATE screen.  
The V.32 extended mode disables the V.32 bis features. In V.32 extended  
mode, the Modem’s functional ability is identical to that of previous models  
of this modem series (the MD833A model prior to incorporation of the  
CCITT V.32 bis recommendation.)  
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3.0 Modem Setup Options  
The 208 Phase Detection option is for 208 mode.  
Normal — Conditions the modem’s 208 receiver for normal modulation  
detection.  
Compensated — Conditions the 208 receiver for compensated  
modulation detection for improved performance with older 208 modems.  
The Answer Tone Detection is for 208 mode.  
Enable — Conditions the originating modem’s receiver to wait for answer  
tone detection before going on-line.  
Disable — Conditions the originating modem to go on-line without  
requiring answer tone detection. This setting accommodates operation  
with automatic calling units that connect the modem to the line at the  
end of answer tone.  
The Multimode Handshake option is for Hayes, V.25 bis, and Dumb modes.  
This option determines how long the Modem will attempt to handshake  
with a V.32 modem before falling back to a lower speed.  
• T1 Timer — If the T1 timer setting is selected, the modem will attempt  
to handshake with a calling V.32 modem for the time specified by the T1  
Timer option.  
V.32 bis ANNEX A — If the V.32 bis Annex A setting is selected, the  
modem will handshake according to the conventions established in Annex  
A of the CCITT V.32 bis recommendation. Handshaking using the Annex  
A selection will generally be faster than handshaking based on the T1  
timer.  
NOTE  
The T1 Timer option (Section 3.3.7, Modem Setups) is only effective if the  
Multimode Handshake option is set to 0 (T1 timer).  
Two additional options, Operating Mode Fallback and V.32 Speed Fallback,  
are discussed in Section 4.9.  
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Modem 34336  
4.0 General Operation and  
Special Features  
This chapter describes the following Modem features and operational  
modes (listed here in the order in which they are presented):  
• Quick reset  
• Dumb mode and Bell 208 operation  
• Security operation  
• Phone number storage  
• Leased Line Auto-Recovery  
• Dial Line Auto-Recovery  
• DTR dialing  
• Diagnostic interface control  
• Automatic fallback  
• V.13 operation  
The status screens, which display data concerning the operational status of  
the modem, are discussed in Chapter 7. Instructions for using the pushbutton  
controls and LCD are included in Chapter 3.  
4.1 Quick Reset  
Quick Reset enables you to reset the modem without powering down the unit.  
For a soft reset of the Modem—when option settings are not changed but the  
modem is cleared for a new start, and the ROM memory chip is checked—  
select RESET from MAIN MENU screen 3. The modem displays the power-on  
screen for a few seconds. Then it displays the EIA status screen.  
4.2 Phone Number Storage  
This feature is used to store a number to be used later for autodialing from  
the front panel, DTR dialing, or for leased line or dial line auto-recovery.  
To store numbers in Hayes mode, see Chapter 5.  
To store a number from the front panel, select PHONE from MODEM  
SETUPS screen 5. The following screen is displayed:  
- - - - - - - - -  
DEC CTRL INC  
1
2
3
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4.0 General Operation and Special Features  
If a number has been previously stored, the number is displayed on the top  
line of the LCD (instead of dashes, as shown above).  
Only one phone number can be stored per cell. To store a phone number,  
use the right and left arrow pushbuttons to go to the digit you want to change.  
The character at the current cursor location flashes. Use pushbutton 1 to  
decrease a number at the current cursor location or pushbutton 3 to increase  
a number. Use pushbutton 2 (CTRL) to sequence through the dialing control  
characters (listed below). Use the arrow pushbuttons to move on to the next  
digit or character to be changed. The phone number is saved when you  
return to the MAIN MENU.  
4.3 Leased Line Auto-Recovery  
When conditions on the leased lines deteriorate, the Leased Line Auto-  
Recovery feature allows the Modem to automatically restore operation for  
a leased line application by using dial lines as a backup. The Modem uses  
signal quality and loss of carrier detect to determine if line conditions  
are unsatisfactory. Leased Line Auto-Recovery is accessed via the AUTO-  
RECOVERY screen on the front panel LCD. The following conditions  
are required for Leased Line Auto-Recovery operation:  
• Leased Line Auto-Recovery must be enabled (using the Leased Line Auto-  
Recovery Select option) on both communicating modems.  
• The Leased Line Auto-Recovery Select, Return and Test options must  
be set correctly on both communicating modems, as explained in the  
following sections.  
• A dial backup line (or lines) must be installed.  
• The phone number to be dialed (the backup line) must be stored  
in the originate modem, as explained in the previous section.  
• Auto-answer must be enabled on the answer modem.  
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Modem 34336  
Table 4-1. Dialing Control Characters.  
Character  
Function  
A-D  
L
Used in some PBX applications (tone dialing only).  
Links a phone number to another number to be  
dialed as an alternate.  
T
P
R
Sets tone-dialing mode.  
Sets pulse-dialing mode.  
Configures modem for Dial Line Auto-Recovery.  
Requires / prefix. See DIAL LINE AUTO-  
RECOVERY section later in this chapter.  
W or : (colon)  
, (comma)  
. (period)  
- (dash)  
(space)  
*
Wait 30 seconds for dial tone before proceeding.  
Inserts 4-second pause.  
Marks end of phone number.  
Used only for clarity (no function).  
Used only for clarity.  
Dial * (tone dialing only).  
#
Dial # (tone dialing only).  
A, B, C and D are used in some private branch exchange (PBX)  
applications. The * and # symbols are sometimes used for access  
to remote computer systems.  
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4.0 General Operation and Special Features  
4.3.1 AUTODIAL BACKUP  
The Modem automatically dials the stored number to connect over the backup  
line if it detects poor signal quality (ER) or a loss of carrier detect (CD) on the  
leased line. The criteria used by the Modem in assessing the condition of the  
leased line depend upon the settings of the Signal Quality option (one error  
in 103 or 105 bits) and the Carrier Detect Level option (-43,  
-33 or -26 dBm).  
When Dial Backup occurs (either automatically or by operator intervention),  
the following message flashes on the front-panel LCD of both modems:  
ATTENTION:  
DIAL BACKUP  
1
2
3
The message clears when the modem returns to the leased line. If you want  
to clear the message while the Modem is still in dial-backup mode, press  
the ENT pushbutton.  
4.3.2 EXIT FROM LEASED LINE AUTO-RECOVERY  
If the Leased Line Auto-Recovery Return option is enabled (see below),  
the Modem automatically exits the Auto-Recovery mode when leased-line  
conditions are satisfactory. Any normal disconnects (such as loss of carrier  
or line current) may also disconnect the dial connections and return  
communication to the leased line. To ensure the proper disconnect  
capabilities for Leased Line Auto-Recovery mode, both the line current  
disconnect (CURRENT DISC’T screen) and carrier disconnect (CARRIER  
DISC’T) options must be enabled on both modems. To manually exit the  
Leased Line Auto-Recovery mode and return to leased line operation, select  
DIAL from MAIN MENU screen 1, and then select HANGUP from the  
AUTO-DIAL screen.  
4.3.3 LEASED LINE AUTO-RECOVERY OPTIONS  
Three options allow you to specify the criteria the Modem uses in  
determining when to enter and exit the Leased Line Auto-Recovery mode:  
• Leased Line Auto-Recovery Select (Select)  
• Return From Leased Line Auto-Recovery (retn)  
• Test Interval (Test)  
The Leased Line Auto-Recovery Select option determines the type of Leased  
Line Auto-Recovery desired. “DIAL IF BAD >> (1, 2, 3 or 4) min” means dial  
backup occurs if bad line conditions are present for the number of minutes  
selected. To disable Leased Line Auto Recovery, select NO AUTO  
RECOVERY. A sixth option, Manual Recovery, is discussed below.  
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Modem 34336  
NOTE  
If DIAL IF BAD >> (1, 2, 3 or 4) min is selected, the Select option setting  
of the answer unit must be equal to or less than the Select option of the  
originate unit.  
If both modems are set for Manual Recovery, the originate unit is used to  
autodial the number stored via the PHONE screen without having to change  
the LINE TYPE setting on either unit. To autodial, access the AUTO-DIAL  
screen and select DIAL. To return to the leased line, select HANGUP from  
the AUTO-DIAL screen.  
The Return From Leased Line Auto-Recovery option determines the criteria  
for exiting the Leased Line Auto-Recovery mode.<D%0> “RETURN IF GOOD  
>> (10, 40, 60, or 120) seconds” means the modem automatically exits the  
Leased Line Auto-Recovery mode when it tests and finds the leased <M%-  
2>line in good condition for more than the time period specified (10, 40, 60  
or 120 seconds).<D%0> If the Return option is set to OFF, the modem stays  
in the Auto-Recovery mode indefinitely, unless you select HANGUP from the  
AUTO-DIAL screen, a loss of line current, or other normal disconnect occurs.  
Either event returns communication to the leased line.  
NOTE  
The Return option setting must be the same on both communicating  
units.  
If the Return option is enabled (>> 10, 40, 60, or 120 seconds), the Test  
Interval selections control how frequently the Modem tests the leased line  
conditions to determine if exit from the Leased Line Auto-Recovery mode is  
desirable. Exiting is based on the criteria selected for return from Auto-  
Recovery. The Modem can be set to test every 10, 20, 40, or 60 minutes.  
NOTE  
The Test option setting must be the same on both units.  
4.4 Dial Line Auto-Recovery  
The Dial Line Auto-Recovery feature allows you to set up the Modem for a  
dial-up application so it automatically redials to restore a broken connection  
if the modem goes on-hook. In this way, the Dial Line Auto-Recovery feature  
emulates the reliability of a leased line connection.  
4.4.1 SETTING UP THE MODEM FOR DIAL LINE AUTO-RECOVERY  
Two steps are required to set up the Modem for Dial Line Auto-Recovery.  
First, enter or store the number to be dialed with the /R command. Then,  
enable Dial Line Auto-Recovery. To configure the Modem for Dial Line Auto-  
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4.0 General Operation and Special Features  
Recovery from the front panel, enter the phone number to be dialed followed  
by /R (the Dial Line Auto-Recovery command) on the PHONE screen  
(shown below).  
T555-4545/R  
DEC CTRL INC  
1
2
3
If you need assistance, see Section 4.2.  
An alternate way to configure the Modem for Dial Line Auto-Recovery  
(in Hayes mode only) is to use the Hayes AT &Z command to store the  
phone number to be redialed and the /R command in memory location 0,  
by entering the following command:  
AT &Z0=T555-4545/R  
Dial Line Auto-Recovery is not enabled until you select DIAL from the front  
panel AUTO-DIAL screen. If power is removed from the modem, select DIAL  
to re-enable Dial Line Auto-Recovery. To disable Dial Line Auto-Recovery,  
select RESET from MAIN MENU screen 3.  
4.4.2 RECOVERY PROCEDURE  
If Dial Line Auto-Recovery is enabled and the Modem goes on-hook, it redials  
the stored phone number up to 10 times. It redials 5 times at 30-second  
intervals, waits 2 hours, and then redials 5 additional times at 30-second  
intervals. The Modem stops redialing after 10 attempts.  
If a connection is broken, re-established, and broken again, the full sequence  
of 10 redial attempts does not occur unless the Modem is on-line for more  
than 1 hour. The modem redials, but it is programmed not to exceed more  
than 10 redial attempts in 1 hour.  
4.5 DTR Dialing  
NOTE  
To use DTR dialing in V.25 bis mode, you must use the Summary Setup  
feature, explained in Chapter 6.  
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Modem 34336  
4.5.1 DIALING A STORED NUMBER  
DTR dialing allows you to set up the Modem to automatically dial a stored  
number even when the autodialer is not enabled.  
To enable DTR dialing, select DTR from the DIALER option screen. When  
DTR dialing is enabled, an OFF-to-ON transition of DTR causes the Modem  
to automatically dial the number previously stored using the front-panel LCD.  
DTR must remain on for at least 50 ms to effect automatic dialing. A 50-ms  
drop of DTR aborts the process or disconnects the call. When DTR goes high  
again for at least 50 ms, the automatic-dialing process begins again.  
4.5.2 ANSWER MODE OPERATION  
If the Modem is set for DTR dialing, it automatically answers without DTR.  
However, it will not transfer data until DTR goes high. The call may be  
terminated by dropping DTR.  
4.6 Dumb Mode And Bell 208 Operation  
Bell 208 operation is available on the Modem only. For additional  
information, see Section 2.4.6. Table 6-2 in Chapter 6 lists dialing parameters  
that may be used to modify Dumb mode or Bell 208 dialing operations.  
MANUAL ORIGINATE/ANSWER OPERATION  
When the Modem is operating in Dumb mode or configured for Bell  
208 operation, data calls may be manually originated from a phone set.  
(Plug the phone into the Modem jack marked PHONE.)  
For manual-originate operation, the remote modem may be configured for  
either automatic or manual answer. For manual originate/answer operation,  
one modem must be set to ANSWER and one must be set to ORIGINATE via  
the ANS/ORG DEFAULT screen. For either type of operation, use the Dumb  
mode or Bell 208 Quick Setup to configure the Modem. (The Dumb mode  
Quick Setup defaults to asynchronous operation; the Bell 208 Quick Setup  
defaults to synchronous operation.)  
Either Quick Setup sets the Modem to originate mode. If you want to set your  
Modem to answer mode, use the front-panel controls to access the ANS/ORG  
DEFAULT screen (MODEM SETUPS screen 4). Then, select ANSWER  
(answer mode). To manually originate a data call, select TALK from MAIN  
MENU screen 1. The MANUAL-DIAL screen is displayed. Select TALK again.  
This puts the Modem in talk mode. Lift the handset and listen for the dial  
tone. Dial the phone number of the remote modem. When you hear a high-  
pitched answer tone, select DATA from the MANUAL-DIAL screen, and  
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4.0 General Operation and Special Features  
place the handset back on the cradle. The LCD displays the status of the  
communication. It appears as shown below.  
D TR MR RS CS  
9600  
CD  
1
2
3
The data link between the two modems is now established, and data transfer  
begins.  
An incoming call may be answered manually or automatically. To answer a  
data call manually, you must disable the Auto-Answer option. Before the call  
is received, the Modem must be set to TALK, as explained in the previous  
section. The first unit that is switched to DATA mode must be set for answer  
mode (using the answer/originate option). The other unit must be set for  
originate mode.  
NOTE  
If you set the Modem to talk mode, the phone rings, but the Modem will  
not answer, even if the Auto-Answer option is enabled.  
After you answer the phone and initiate a conversation with the caller, the  
Modem must be set for data mode. With the MANUAL-DIAL screen still  
displayed, select DATA to put the Modem in data mode.  
The first person to go to data mode hears his telephone disconnect as his  
modem connects. The other person must wait until he hears an answer tone,  
and then switch to data mode (select DATA). When both modems are in data  
mode, the data communication begins. The LCD displays the status of the  
connection.  
There are several ways a data call can be terminated. You can terminate a call  
through communication software by following the software manufacturer’s  
instructions. An alternate method is to switch to the TALK option (talk  
mode) on the MANUAL-DIAL screen, as described in the previous section.  
Or you can drop the DTR signal from the DTE (by software control or by  
turning the DTE off).  
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4.7 Modem Security Operation  
In 2-Wire-Dial Hayes emulation mode only, the Modem can be configured to  
provide security on incoming calls. Remote users attempting to connect to the  
Modem are required to enter a password. Incoming calls are accepted only if  
the user enters a valid password.  
NOTE  
The security features described in this manual provide a deterrent to  
unauthorized access. No communications system can be made perfectly  
secure.  
PASSWORD PROTECTION  
NOTE  
Password protection functions only if the Modem is in Hayes emulation  
mode, error correction and/or buffer mode are enabled, and the data  
format is asynchronous.  
In Hayes mode only, the Modem can be configured for two types of security  
operation: security callback or password pass-through operation. Both types of  
security operation provide security on incoming calls by requiring remote  
users to enter a valid password. In addition, access to Hayes compatible  
commands for viewing and storing phone numbers is password-protected.  
If callback operation is enabled, the Modem calls back an authorized user  
after he or she enters a valid password. If pass-through operation is enabled,  
the Modem passes a connection on to the DTE interface only after it receives  
a valid password.  
The password-protection scheme used by the Modem for incoming calls is  
summarized below.  
• A remote modem calls the local Modem.  
• Local Modem answers.  
• Remote user sends carriage return [CR].  
• Local Modem sends PASSWORD? query, displayed on remote terminal.  
• Remote user sends unique password (assigned to remote modem).  
• Local Modem confirms password and, according to the password, grants  
access (if programmed for pass-through operation) or initiates security  
callback.  
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4.0 General Operation and Special Features  
The modem’s security configuration for password protection is controlled  
from the DTE by a special set of password commands. The commands are  
implemented by using the Hayes AT &Z command to store them in memory.  
If an administrative password is implemented, the AT &Z command will not  
function until it is unlocked.  
The Modem incorporates 10 memory locations for storing telephone  
numbers, passwords, and the password commands listed in Table 4-2. To  
implement a security command, use the Hayes AT &Z command to store the  
command in a specific memory location. The password commands are listed  
in Table 4-2 and explained in detail in the sections that follow.  
Table 4-2. Password Commands  
COMMAND FUNCTION  
EXAMPLE1  
MEM.LOC.2  
/A  
Set/change administrative  
password; password-  
protects use of certain  
Hayes commands.  
/ASECURITY  
/PYELLOW  
1
/P  
Set password for  
pass-through  
operation or  
security callback  
operation  
4443535/PGREEN  
2-49  
/U  
User-defined text string.  
Used to send a response  
to the remote terminal  
user after a valid  
password is received.  
/UCONNECTED  
0
1Command string stored using AT &Z commands.  
2Each command will function only in the listed memory locations.  
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Modem 34336  
Rules for using passwords and password commands are listed below.  
• Memory locations 0 and 2-9 may be used for storing phone numbers;  
locations 2-9 may be used to store passwords.  
• The entire command string, including the AT &Z command,  
cannot exceed 40 characters.  
• Passwords and commands may be entered in capitals or lowercase letters.  
They are stored and displayed as capitals.  
• For password pass-through operation, / must be the first character in  
a storage location. For security callback operation, a phone number  
must be listed first in a storage location.  
• Special characters (! @ ? , etc.) may be used for passwords entered with  
the DTE interface, but these characters cannot be entered with the  
Modem's front panel.  
• A phone number cannot be stored after / .  
• Only one command (/A, /P, or /U) can be stored in each memory  
location.  
• Do not leave a space after a command.  
• When using the /U command, do not include spaces or control characters  
in the specified text string.  
The following instructions explain how to use the password commands.  
1.Establishing or changing the administrative password. For greatest  
security, you should use an administrative password. If implemented,  
the administrative password controls access to the Hayes compatible &V  
and &Z commands. The commands are required to view or modify the  
modem’s security configuration (as explained in the following sections).  
To establish or change an administrative password enter the following  
command replacing SECURITY with your password:  
AT &Z1=/ASECURITY  
NOTE  
The administrative password may be stored only in memory location 1.  
The command line, including AT &Z1=, cannot exceed 40 characters.  
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4.0 General Operation and Special Features  
2.Unlocking the &V and &Z commands. If an administrative password is  
implemented, the Hayes compatible &V and &Z commands cannot be  
accessed unless they are first unlocked using the current administrative  
password. (&V is used to view the active modem configuration, stored  
phone numbers, password commands and passwords; &Z is used to store  
phone numbers, password commands and passwords). To unlock the  
&V and &Z commands, enter the following command; substituting  
your password for SECURITY:  
AT &Z1=/ASECURITY  
The &V and &Z commands are accessible. To re-lock the &V and &Z  
commands, enter AT Z. The DTE responds with OK, and the &V or &Z  
commands will not function until they are unlocked.  
3.Programming security callback operation. Use the commands AT& Z and  
/P to specify the callback phone number and password to be used. The  
following example programs memory location 3 for callback operation:  
AT &Z3=T5551212/PVIOLET  
The callback number in this example is 555-1212 (with T used to specify  
tone dialing); the password is VIOLET. A remote user can now call from  
the specified callback number, 555-1212. After the modems connect, the  
remote user presses the Enter key. The DTE prompts the user to enter  
the assigned password by displaying the PASSWORD? query. Upon  
receipt of the correct password, VIOLET, the local Modem calls back the  
remote user at 555-1212. Once this connection is established, data may  
pass freely.  
NOTE  
Callback numbers and passwords may be stored only in memory  
locations 2 through 9.  
4.Programming pass-through operation. Use the commands AT &Z and /P  
to specify the password used for pass-through operation. The following  
example programs memory location 5 for pass-through operation:  
AT &Z5=/PYELLOW  
The password is YELLOW. The DTE prompts the user to enter the  
assigned password by displaying the PASSWORD? query. If the user  
enters the correct password, YELLOW, the call is connected.  
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Modem 34336  
NOTE  
Passwords may be stored only in memory locations 2 through 9.  
5.Programming a response to a correct password. Enter the following  
command, replacing CONNECTED with your message:  
AT &Z0=/UCONNECTED  
The DTE responds with the specified message when the modem receives  
a correct password.  
NOTE  
The /U command and message can be stored only in memory location 0.  
4.8 Modem-Controlled Remote Control  
Certain modems can be used to remotely control other modems. Alternately,  
modems may be remotely controlled from a computer or other DTE. This  
section explains modem-controlled remote control. Remote control from a  
DTE is explained in Section 4.9.  
Two types of modem-controlled remote control are possible:  
Direct modem-to-modem control—One modem can be used to control  
the front panel of another modem through a phone link.  
Control through a rack controller—A modem in a rack enclosure equipped  
with an intelligent rack controller can control:  
Another modem in the same rack or  
A remote modem connected to any modem in the rack.  
For both types of remote control, the controlling modem and the controlled  
(remote) modem must be connected at a data rate that uses trellis coding.  
(This does not apply, however, if both modems are installed in the same rack  
and the rack is equipped with a rack controller.)  
4.8.1 DIRECT MODEM-TO-MODEM REMOTE CONTROL  
REMOTE screen 1 on the LCD allows you to use one Modem 34336 to  
control the front panel of another Modem 34336 via a phone link. (REMOTE  
screen 2 is discussed in Section 4.8.2.)  
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4.0 General Operation and Special Features  
Control Procedure (Modem-to-Modem)  
Enabling Modem-to-Modem Remote Control Mode  
To remotely control a modem connected by a direct phone link,  
access REMOTE screen 1 (shown below).  
REMOTE  
CONTROL  
<1>  
TEST  
If you select CONTROL, you will be able to control the front panel of the  
remote modem from the front panel of the modem you are using. When  
you select CONTROL, you will see (on the LCD of the modem you are using)  
whatever is currently displayed on the LCD of the remote modem. The  
characters on the LCD will be displayed in lower case—this is to let you  
know you are actually looking at a “copy” of the LCD of the remote modem.  
Buttons pressed on the front panel of the controlling modem will affect the  
controlled modem (and not the controlling modem). When you are remotely  
controlling another modem, the LCD will not change as quickly as it normally  
does.  
NOTE  
While a Modem 34336 is being remotely controlled by another Modem  
34336 or is remotely controlling another Modem 34336, its diagnostic  
port cannot be used for other purposes—commands from the diagnostic  
port will be ignored.  
(You can also access two remote test options from REMOTE 1 screen by  
selecting TEST. These test options, remote digital loopback and remote  
digital loopback self test, are described in Chapter 7.)  
Exiting from Remote Control Mode  
To exit from remote control mode, press the ENT pushbutton five times in  
succession on the front panel of the controlling modem. (If the remote  
modem resets as a result of a configuration change, the local modem will  
appear to have no control. To remedy this situation, press the ENT button  
five times.)  
4.8.2 REMOTE CONTROL THROUGH A RACK CONTROLLER  
When installed in a rack enclosure equipped with an intelligent rack  
controller, the Modem 34336 can be used to control:  
• Another modem in the same rack or  
• A remote modem connected to any modem in the rack (address control  
mode only).  
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Modem 34336  
Remote control through a rack controller is an especially valuable capability  
for modem used in high-density 16-slot enclosures. The low-profile modems  
specially designed for these racks are manufactured without an LCD user  
interface or control pushbuttons. One way to access the low-profile modems  
to monitor, test, or configure tham is by using the modem-control feature  
described below.  
The controlling modem must be a Modem 34336 equipped with a front-panel  
LCD and pushbuttons. (Low-profile rackmount versions of these modems  
cannot be used as controlling modems because they do not have LCDs and  
pushbuttons.) The controlling Modem 34336 can control another Modem  
34336.  
Control Procedure (Using a Rack Controller)  
Enabling Remote Control through a Rack Controller  
The main screen used to control other modems through a rack controller  
is REMOTE screen 2 (shown below).  
REMOTE  
<2>  
CONTROL ADDR/C ADDR  
This screen is used as follows:  
1. Select address control or slot control—To control a modem in the  
same rack as the controlling modem, or to control a connected remote  
modem, you must first specify the address or slot number (location in  
the rack) of the modem you want to control. If you want to specify the  
modem by its address, select ADDR/C (address control) on the bottom  
line of REMOTE screen 2.  
NOTE  
Each modem must have a unique address.  
If you want to specify the modem by its slot number, select SLOT/C.  
(For slot 16, use 00 or 16, whichever is displayed on your modem.) Press  
pushbutton 2 to toggle between ADDR/C and SLOT/C (slot control).  
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2. Enter the address or slot number—To enter the address or slot number  
of the modem to be controlled, press pushbutton 3. If ADDR/C is  
displayed on REMOTE screen 2, a screen showing ADDRESS: 000,000 on  
the top line will be displayed. If SLOT/C is displayed on REMOTE screen  
2, a screen showing SLOT NUMBER: 01 on the top line will be displayed.  
Enter the address or slot number as follows: Use the right and left arrow  
pushbuttons to go to the digit you want to change. Then use pushbutton  
1 to decrease (DEC) a number or pushbutton 3 to increase (INC) it.  
If SLOT/C is selected, only modems in the same rack as the controlling  
modem may be specified (slots 1–16). However, if ADDR/C is selected,  
you can specify any modem in the same rack with the controlling modem  
or a remote modem connected to any modem in that rack (Figure 4-1).  
The remote modem may be in a rack without a rack controller, or it may  
be a standalone modem.  
When the address or slot number you want is shown, press ENT. The LCD  
will return to REMOTE screen 2.  
3. Initiate control—After entering the address or slot number of the modem  
to be controlled, select CTRL from REMOTE screen 2. “CTRL” will flash  
on and off for about seven seconds until the connection to the specified  
modem is made. When the connection is made, all characters on the LCD  
of the controlling modem will be in lower case instead of capitals—this  
indicates that the screens displayed are for the controlled modem.  
Buttons pressed on the front panel of the controlling modem will affect  
the controlled modem (and not the controlling modem).  
If the specified modem is not present or is not working, the LCD will  
display a “NO RESPONSE” message. If a rack controller is not installed  
on the rack enclosure or is not working, “CTRL” will continue to flash  
on and off indefinitely (until you exit from the address or slot control  
mode).  
Exiting from Remote Control Mode  
To exit from the address or slot control mode, press the ENT button five  
times in succession. (If the remote modem resets as a result of a configuration  
change, the local modem will appear to have no control. To remedy this  
situation, press the ENT button five times.)  
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Modem 34336  
Modems in rack equpped  
with rack controller  
This modem, with LCD  
pushbuttons, can control any  
of the shaded (gray) modems.  
Modems in rack with or  
without rack controller  
Standalone modems  
Figure 4-1. Remote control—address control mode.  
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4.0 General Operation and Special Features  
4.9 Diagnostic Interface Control  
The diagnostic software built into the Modem supports a special set of  
commands known as diagnostic port commands. The commands (listed  
in Table 4-3) are used to configure modems (from either a local or remote  
location), or to monitor modems for diagnostic purposes. The diagnostic  
port commands are entered from a computer or terminal keyboard.  
NOTE  
To configure or otherwise control a remote modem, the data rate must be  
9600 bps or higher.  
4.9.1 DIAGNOSTIC PORT  
The Modem’s diagnostic port is an 8-pin RJ-45 connector allowing you to  
test or configure the Modem from a connected computer or other DTE.  
The location of the diagnostic connector next to the power connector on  
the modem’s rear panel is shown in Figure 2-1. The diagnostic connector  
requires a cable with an RJ-45 modular connector on one end (modem) and  
a DB25 connector on the other (terminal) end. The pin assignments of this  
connector are shown below.  
Pin  
1
Function  
Constellation X output  
Constellation Y output  
Not used  
2
3
4
Ground  
5
Receive data (output from  
modem)  
6
Transmit data (input to  
modem)  
7
8
Not used  
Not used  
4.9.2 DIAGNOSTIC PORT COMMANDS  
The diagnostic software built into the Modem supports the diagnostic port  
commands listed in Table 4-3. These commands are issued from a computer  
or other DTE, which must be connected to the modem’s diagnostic port.  
To communicate with a modem via the diagnostic port, the DTE must be  
configured for 8-bit character length, no parity, 1 stop bit, and a data rate  
of 9600 bps.  
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Modem 34336  
Table 4-3. Diagnostic Port Commands.  
COMMAND  
FUNCTION  
CONNECT g,u Connect to diagnostic port of modem at group address  
g, unit address u. An address must be specified unless  
the wildcard character * is used: CONNECT *  
(meaning Connect to local modem; address  
unknown/unspecified.). When the connection is made,  
the DTE displays the modem’s address. Echo, line  
feed, and Auto-Display are enabled.  
CON g,u  
CON performs same functions as CONNECT  
command, except that echo, line feed, and Auto-  
Display are disabled. The wild card character * may be  
used: CON * .  
NOTE: The remaining commands listed in this table will function only if  
CONNECT or CON (with address or *) has been previously issued.  
D
Displays the current front-panel LCD screen of the  
connected modem on the DTE monitor.  
E
Performs same function as front panel ENT button.  
(Exits from screen.)  
1, 2, or 3  
> or .  
< or ,  
RESET  
FRESET  
Performs same functions as corresponding buttons on  
front panel. (Selects choice 1, 2, or 3 from LCD.)  
Performs same function as right arrow on the modem  
front panel. (Displays next menu screen.)  
Performs same function as left arrow on the modem  
front panel. (Displays previous menu screen.)  
Resets the Modem without changing option settings.  
(Same as selecting RESET from the MAIN MENU.)  
Resets the Modem to factory defaults. (Reconfigures  
modem to Hayes mode default settings).  
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A carriage return [CR] is required at the end of a command line except  
when the command line consists of only one single-character command.  
Commands can be entered in upper or lower case.  
Other diagnostic port commands are available for factory use only.  
Therefore, some commands that are not listed above may produce  
a response.  
When an address is specified with the CONNECT or CON command,  
leading zeros are ignored, meaning that any of the following forms will work:  
CONNECT 3,22  
CONNECT 003,022  
CON 000003,22  
If a group or unit address is not specified, it is assumed to be zero:  
CONNECT, 3 (same as CONNECT 0,3). Note that a comma is required,  
even if no group or unit number is used.  
4.9.3 RESPONSES TO DIAGNOSTIC PORT COMMANDS  
In response to the diagnostic port commands listed in Table 3-3, the  
Modem may display the responses listed in Table 4-4 on the DTE monitor.  
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Modem 34336  
Table 4-4. Responses To Diagnostic Port Commands.  
RESPONSE  
ERROR  
MEANING  
Command error (incomplete, wrong syntax, etc.). (If  
CONNECT or CON is issued without an address or *, the  
modems will not connect, and there will be no ERROR  
message.)  
ADDRESS g,u The Modem has connected with diagnostic port of modem  
at address g,u (group and unit). Address may be  
preceded by A, S, or both—see below.  
A
One or more modem alarms has been detected. An alarm  
indicates a condition that may require attention (power  
loss, loss of carrier, etc.).  
S
Valid statistics have been collected on a call or attempted  
call. Statistics include information such as call duration  
call, signal quality level, etc.  
RESET  
Response to RESET command. Prompt ( >) appears when  
reset is complete.  
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4.0 General Operation and Special Features  
4.9.4 DTE DISPLAYS  
When Auto-Display is enabled, an update of the LCD is automatically  
displayed on the DTE screen each time a command (E, 1, 2, 3, left arrow,  
or right arrow) is entered to control the front-panel LCD on the connected  
modem. Auto-Display is enabled when the long-form connect command  
(CONNECT) is used.  
Auto-Display is disabled when the CON command is used. However, even  
with Auto-Display disabled, the D command can be used to display the LCD  
screen.  
The CONNECT command also enables echo and line feed on the DTE  
screen, whereas both are disabled when CON is used. Data from the  
connected modem is easier to read when CONNECT is used; however,  
data throughput is faster if CON is used.  
On the Modem’s front-panel LCD, a selected option flashes so it is easily  
identified as the current selection. When an LCD display is sent to the DTE  
in response to the CONNECT command, characters flashing on the LCD  
are indicated on the DTE screen by asterisks. An asterisk appears below each  
flashing character. In the example below, the selected CTS to EIA option  
is TRUE.  
Actual LCD on connected modem:  
CTS to EIA  
NORM RTS TRUE  
DTE display:  
CTS to EIA  
NORM RTS TRUE  
****  
Asterisks denoting flashing characters are also displayed if the D command  
is used to request a display of the LCD—provided the connect command last  
used was CONNECT and not CON. Even when the CON command is used  
(meaning the LCD of the connected modem is not automatically displayed),  
a computer reading data from the diagnostic port is able to determine which  
characters are flashing because bit 7 (MSB) is set in each flashing character.  
4.9.5 DISCONNECTING FROM A DIAGNOSTIC LINK  
There are two ways to disconnect from a modem-DTE diagnostic link:  
• If you want to connect to another modem, issue the CONNECT command  
followed by the address of the modem to which you want to connect.  
The DTE disconnects from the first modem and immediately connects  
to the one you specified.  
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Modem 34336  
• If you want to disconnect from the diagnostic link without establishing  
a new link, issue the CONNECT command without an address.  
4.10 Automatic Fallback  
The Modem incorporates two automatic fallback features that are controlled  
by the user:  
Operating Mode Fallback—Provides compatibility with modems that use  
any of several different operating modes.  
V.32 Speed Fallback— Allows the Modem to automatically select the  
highest possible data rate, depending on the signal quality during  
handshake.  
Both of the above fallback features function when the modem is in either  
manual or automatic originate mode, or manual or automatic answer  
mode.  
4.10.1 OPERATING MODE FALLBACK  
This section applies to dial-line operation only.  
When the Modem originates or answers a call, it determines from the  
handshake routine with the other modem the most efficient operating mode  
that is supported by the other modem and automatically falls back to that  
mode. The Modem supports two alternatives for operating mode fallback:  
V.22 bis/Bell 212A/Bell 103 fallback operation (default setting) and V.22  
bis/V.22/ V.21/V.23 fallback operation. For communication within the  
United States, use the default setting for Operating Mode Fallback: V.22  
bis/Bell 212A/Bell 103.  
To configure the modem for V.22 bis/V.22/V.21/V.23 fallback operation,  
refer to Appendix C. Follow the instructions given there to change the value  
identified in the MISCELLANEOUS OPTIONS diagram (Appendix C) as  
the Operating Mode Fallback parameter from 0 (default setting) to 1.  
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4.0 General Operation and Special Features  
Changing the Operating Mode Fallback parameter to 1 has the following  
effects:  
• The Modem is configured for V.22 bis 2400 bps/V.22 1200 and 600  
bps/V.21 300 bps/V.23 1200/75 bps fallback operation. As a result,  
600 and 1200/75 bps appear as additional selections on the SPEED  
LIMIT LCD screens.  
• Fallback to V.22 bis Bell 212A and Bell 103 compatibility is disabled.  
• An AT command is available (in Hayes mode only) that allows control  
over operating mode as follows: F0—Multi-mode operation (default);  
F1—V.21, 300 bps; F2—V.22, 600 bps; F3—V.23, 1200/75 bps; F4—V.22,  
1200 bps; F5—V.22 bis, 2400 bps; F6—V.32 (highest common speed).  
Except for multi-mode operation, the mode and speed are limited to the  
mode and speed specified. Multi-mode operation allows the modem to  
automatically fall back to the most efficient mode that can be used by  
both modems.  
The preferred mode is V.32 (9600 or 4800 bps, asynchronous/ synchronous,  
full duplex); however, if the other modem does not support the V.32  
standard, the Modem falls back to one of the modes listed below. The fallback  
modes are listed in the order in which they are attempted by the Modem in  
normal operation.  
Table 4-5. V.22 bis/BELL 212A/BELL 103 FALLBACK (DEFAULT).  
MODE  
DESCRIPTION  
V.22 bis  
Bell 212A  
Bell 103  
2400 bps asynchronous/synchronous  
1200 bps asynchronous/synchronous  
0-300 bps asynchronous  
All modes are full duplex.  
If V.22 bis/V.22/V.21/V.23 fallback operation is enabled, the following  
fallback modes are available. As in the previous list, the modes are listed  
in the order in which they are attempted by the Modem.  
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Modem 34336  
Table 4-6. V.22 bis/V.22/V.21/V.23 FALLBACK.  
MODE  
V.22 bis  
V.22  
DESCRIPTION  
2400 bps asynchronous/ synchronous  
1200 and 600 bps asynchronous/synchronous  
300 bps asynchronous  
V.21  
V.23  
1200/75 bps asynchronous  
All modes are full duplex.  
The operating mode is controlled through the SPEED LIMIT screens on the  
LCD in all modes except Hayes mode. See Chapter 3 for details.  
4.10.2 V.32 SPEED FALLBACK  
This feature applies only to V.32 mode operation. It functions only if enabled  
and the maximum speed is set (via the Speed Limit option) to the highest  
available speed—9600 bps for the Modem, 14,400 bps for the Modem.  
When V.32 Speed Fallback is enabled, the Modem automatically selects the  
highest possible data rate, depending on the signal quality during handshake.  
The Modem automatically selects either 9600 bps or the fallback rate of  
4800 bps. The Modem selects either 14,400 bps or the fallback rate of  
12,000 bps. If the error rate is one error in 1000 bits or lower, the Modem  
connects at the highest available rate. If the error rate exceeds this threshold,  
the Modem connects at the fallback rate. Fallback may also occur during  
retrain sequences.  
To configure the modem for automatic V.32 Speed Fallback, refer to  
Appendix C. Follow the instructions to change the value identified in the  
DATA PUMP OPTIONS diagram (Appendix C) as the V.32 Speed Fallback  
parameter from 1 (default setting) to 0.  
Rate Renegotiation Procedure (RRP)  
Rate Renegotiation Procedure (RRP) is a third type of automatic fallback;  
it can be controlled by the user.  
Like V.32 Speed Fallback, RRP allows the Modem to automatically select the  
highest possible data rate, depending on the signal quality. Unlike Speed  
Fallback, RRP allows for data rate fallback or fallforward at any time during  
data trans-mission. Retraining is not required. RRP may be used with either dial-  
up lines or leased line operation.  
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4.0 General Operation and Special Features  
If Rate Renegotiation Procedure (RRP) is enabled, the modem will  
automatically fall back or fall forward to a lower or higher data rate in  
response to changes in signal quality. This may happen at any time during  
data transmission, and it is done without a retraining procedure. Your data  
transmission is virtually uninterrupted.  
Note that data-rate adjustments are limited:  
• to the range of 4800 to 14,400 bps for the Modem  
(4800 to 9600 bps for the Modem 3242–S)  
• by the minimum and maximum rate settings of the Speed Limit option.  
If satisfactory performance cannot be attained at any of the available data  
rates, the Modem will initiate a GSTN cleardown (line disconnect). If the  
originate modem attempts to negotiate a rate that is lower than the minimum  
rate setting of the answer modem, the answer modem will initiate a GSTN  
cleardown.  
How to Enable or Disable RRP  
NOTE  
RRP will function only if Speed Fallback is enabled (factory default) and  
if the V.32 Mode option is set to V.32 bis (factory default). Both functions  
are Summary Setup options.  
The factory-default setting for RRP is enabled. To change the RRP option,  
refer to the DATA PUMP OPTIONS diagram in Appemdix C. Change the  
Rate Renegotiation Procedure (RRP) parameter shown in the diagram to 0  
(disable) or 1 (enable). This is the only way the RRP option can be changed.  
Rate Change Screen  
If V.32 bis mode and the Rate Renegotiation Procedure (RRP) option are  
both enabled, the Modem will automatically adjust during data transmission  
to a higher or lower data rate, depending on the receive signal quality. For  
diagnostic purposes, the RATE screen (accessed from screen 3 of the MAIN  
MENU, as illustrated below) may be used to manually initiate speed renego-  
tiation from the front panel, as explained below.  
NOTE  
The RATE screen is only displayed if V.32 bis mode is enabled  
(via Summary Setup, V.32 Mode option).  
If you select DOWN from the RATE screen, the Modem will fall back to the  
next-lower speed. If you select UP, the modem will fall forward to the next-  
higher speed if the signal quality is good enough. Remember, the data-speed  
range within which the Modem can fall forward or fall back is limited by the  
minimum and maximum rates set via the Speed Limit option.  
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Modem 34336  
After you select UP or DOWN, the LCD will automatically switch to the EIA  
status screen so you can see the result of the rate-change request (i.e., the  
current data rate, which is displayed in the lower left corner of the EIA status  
screen). However, if the Modem has reached the minimum or maximum  
speed, it will not switch to the EIA status screen.  
NOTE  
A request to increase the data rate may result in no change in the data  
rate if the signal quality is poor.  
If you manually initiate speed renegotiation with RRP enabled, the modem  
will automatically renegotiate the speed (again) after four seconds. If the  
originate modem attempts to negotiate a rate that is lower than the minimum  
rate setting of the answer modem, the answer modem will disconnect (GSTN  
cleardown).  
4.11 V.13 Operation  
The Modem can be configured for CCITT V.13 operation (which emulates  
half- duplex operation) for either point-to-point or multidrop applications.  
(The correct options for these applications are identified in Chapter 2.) The  
Modem normally operates in full duplex; however, some applications (such as  
certain network environments) may require control of a remote CD signal by  
a local Request to Send (RTS) signal. V.13 operation allows local RTS control  
of a remote CD signal without actual ON-OFF switching of the modem  
carrier.  
The following paragraph explains how the Modem responds to RTS signals  
when it is configured for V.13 operation.  
When RTS is raised HIGH by the terminal, the V.13 ON PATTERN is sent.  
The Modem then raises CTS and data can be sent. When RTS is brought  
LOW, the V.13 IDLE PATTERN is sent, and the Modem drops CTS. (If V.13  
TX is enabled but the Modem's data pump is not ready to send, i.e., if it is  
training or retraining, raising RTS causes CTS to be raised, but the V.13 ON  
PATTERN is not sent.) When V.13 RX is enabled, CD turns ON if the V.13  
ON PATTERN is detected; CD turns OFF if the V.13 IDLE PATTERN is  
detected or if the Modem retrains, loses carrier, or is reset.  
RATE  
DOWN  
MAIN MENU <3>  
RESET RATE  
UP  
1
2
3
1
2
3
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5.0 Hayes Emulation Mode  
5.0 Hayes Emulation Mode  
For easy reference, the following tables appear consecutively at the end of this  
chapter:  
• Table 5-1. Hayes Compatible Commands  
• Table 5-2. Hayes Mode Result Codes  
• Table 5-3. S Register Functions  
5.1 Hayes Mode Autodialer  
When the Hayes emulation mode is enabled, the Modem emulates a Hayes  
autodialer and functions like a Hayes modem. Commands are issued from  
the computer keyboard (or other DTE), and the Modem is compatible with  
software written to drive a Hayes style AT command set.  
5.1.1 ENABLING THE HAYES MODE AUTODIALER  
You can enable the Hayes mode autodialer either by using the Quick Setup  
feature or by selecting HAYES from the DIALER screen:  
• Quick Setup. If you use the Quick Setup feature to select 2-Wire Dial  
(Hayes), the Hayes mode autodialer is enabled, and all modem options  
are automatically set to a preset configuration suitable for typical Hayes  
mode applications. To select the 2-Wire Dial (Hayes) Quick Setup,  
access QUICK SETUP screen 1 on the LCD and press pushbutton 2.  
• Dialer Mode. If you enable the Hayes mode autodialer using the Dialer  
Mode option, no other options are changed. Select DIALER from SETUP  
screen 2. Then, select HAYES from the DIALER screen.  
5.1.2 COMMAND GUIDELINES  
The following guidelines for using Hayes compatible AT commands also  
provide a summary of the fundamentals of Hayes mode autodialer operation.  
Note that although carriage returns are not shown in the examples in this  
chapter, a carriage return is required at the end of each command line.  
Escape Sequence (+++). The escape sequence causes the modem to  
escape from the data transfer mode so it can interpret commands.  
(Alternate characters for the escape sequence can be assigned via S  
register S2.)  
Attention Code. AT, the attention code, must begin all command lines.  
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Modem 34336  
• Command Sequence. For dialing, a command line begins with AT,  
followed by a D and the phone number. Other commands should be  
placed before the dial command—or after the dial command if it is  
terminated with a semicolon. See the example below:  
AT M2 V1 D 555-1212; S2=1O  
The above command instructs the Modem to keep the speaker on (M2),  
send word result codes (V1), dial (D) 555-1212, end dial command, set  
register 2 to 1 (S2=1), and go on-line and wait for carrier (O).  
Characters not in the command set are ignored during the dial  
command. Therefore, you can include punctuation or spaces in  
the telephone number for easier reading. See the example below:  
AT DT 9,(212)555-1234 or  
AT DT 9, 212 555 1234  
• A/ Command. Repeats the commands included in the previous command  
line. Because the AT is also repeated, no AT is needed to begin this  
command, nor is a carriage return needed. A/ is useful for redialing  
a telephone number.  
Backspace Key. The backspace key deletes the last character entered  
(provided there is no intervening carriage return) and is used for simple  
editing.  
• Carriage Return [CR]. A carriage return is required at the end of a  
command line. The modem will not execute a command without it. A  
carriage return is sent from the DTE keyboard. A period, which may be  
entered via the modem’s front panel (PHONE LCD screen), has the same  
function as a carriage return. (On most keyboards, the carriage return  
[CR] key is labeled Enter or Return.)  
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5.0 Hayes Emulation Mode  
Dial Command Modifiers. Several modifiers can be used with the  
basic D (dial) command to alter dialing operations. The modifiers  
are explained below.  
Dial Command Modifiers:  
L — Links a phone number to another number to be dialed as an  
alternate  
P — Sets pulse-dialing mode  
S=m — Dial number stored at memory location m  
T — Sets tone-dialing mode  
W or : (colon) — Wait for dial tone before proceeding  
, (comma) — Pause for 2 seconds  
; (semicolon) — Return to command state after dialing  
@ — Wait for silence  
! (exclamation) — Flash  
With few exceptions, dial-command modifiers function only if they are  
used in a command line with the D command, or if they are included  
in a stored number. A carriage return or period must be used at the  
end of a dial string.  
An example of a command line with two dial modifiers is shown below.  
AT DT 9,555-1212  
The modifier T instructs the modem to tone-dial. The comma instructs  
the modem to pause after dialing 9 before it dials the remaining digits.  
• Missing Parameter. A missing parameter is interpreted as a zero.  
For example, the E command (echo) can be sent as either E0 or E1,  
but if an E alone is sent, the Modem interprets it as if an E0 was sent.  
• Command Buffer. The command buffer holds a maximum of 40  
characters. If the command line exceeds 40 characters, the modem  
refuses to execute any portion of the command line and sends an error  
message. The AT at the beginning of the command line, control  
characters, and spaces do not take up space in the command buffer.  
Punctuation (except for spaces) does take up space in the command  
buffer.  
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Modem 34336  
5.1.3 RESULT CODES  
Result codes (see Table 5-2) are messages sent by the modem to the DTE  
monitor in response to your commands. Result code options are selected  
using the V and X commands, as explained below.  
Result codes may be words (V1 command) or digits (V0). Word codes are  
preceded and followed by a carriage-return, line-feed sequence. Digit codes  
are followed by a carriage return. The result codes and their meanings are  
summarized below:  
Result codes 0-4 comprise the basic result code set: OK, CONNECT, RING,  
NO CARRIER, and ERROR. Codes 5-43 provide additional response  
information, as explained in Table 5-2. Various combinations of these codes  
can be enabled or disabled by using the X command and its four parameters.  
5.1.4 TRANSMISSION SPEED  
Transmission speed is governed by the speed of the system with which you  
wish to communicate. You must set the transmission speed of your computer  
by setting a switch in the hardware or by issuing a software command. (Refer  
to your computer documentation.) When the Modem originates a call, it  
automatically detects and adjusts to the transmission speed set when the  
communication port was initialized.  
When answering a call, the Modem determines the transmission speed from  
the carrier signal of the originating modem. Change the setting of your  
equipment to match that of the remote system. Other-wise, unintelligible  
data appears on your screen. (Depending on the parameter used with the  
X command, the speed is indicated by the CONNECT response code.)  
When a call is originated in Hayes mode, the AT attention code causes the  
Modem to autobaud and override any front-panel Speed Limit or DTE Speed  
settings. The speed at which the Modem autobauds defines the speed limit for  
subsequent connections. If the unit is not autobauded, the default interface  
rate is 38,400 bps.  
5.2 Hayes Compatible Commands  
All Hayes compatible commands that are used with the Modem are listed  
in Table 5-1 (near the end of the chapter). More detailed information is  
provided below for selected Hayes commands—particularly those used to  
answer and originate calls, and other commonly used commands. For Hayes  
commands that control modem options, additional information on options  
may be found in Chapter 3. Commands are listed in alphabetical order in  
this section and in Table 5-1.  
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5.0 Hayes Emulation Mode  
For most commands, there are parameters—numerical values used with  
the command specifying the function of the command. For example, the  
command L controls the modem’s speaker volume. L2 sets the volume to  
medium. The default value is a predetermined value which is in effect the  
first time the Modem is powered up or when a reset command is given.  
The possible parameters and default value for each command are shown  
in Table 5-1.  
• A — Quick Answer. The A command immediately puts the modem  
into the answer mode. The modem will not execute any command  
entered in the command line after A.  
The A command is used to transfer a call between two individuals to a  
communication between their computers: One person enters A while  
the other enters D.  
A/ — Repeat Previous Command. A/ is most commonly used to redial  
a busy telephone number. The AT prefix is not used with A/, and no  
carriage return is required. Commands are available for repetition in the  
command buffer only until AT is entered or power to the unit is turned  
off. A/ will not work following an AT or after the power has been turned  
off and back on.  
D — Originate Mode For Dialing. The modem dials the number that  
follows and attempts to go on-line. The dial command D is followed by  
either a telephone number to be dialed, or a string consisting of a phone  
number and dial command modifiers (e.g., T, P, and ; ). An example of  
the D command is shown below:  
AT D3331234.  
In response to the command above, the Modem dials the telephone  
number 333-1234, and then waits for a carrier tone from the remote  
modem (default wait time is 30 seconds). If the modem is able to establish  
a call, it gives a CONNECT result code, indicating that it is on-line. If it  
cannot connect, it issues a different result code, such as NO CARRIER,  
BUSY, or NO DIALTONE. The characters that can be dialed are 0  
through 9, A, B, C, D, #, and *.  
AT D — the dial command without a telephone number causes the  
modem to pick up the telephone line without dialing a number.  
DS —Dial Stored Number. The DS command instructs the Modem to  
dial a telephone number or dial string previously stored using the &Z  
command. The syntax is DS=m, with m specifying the memory location  
where the dialed number will be stored. Up to ten numbers may be stored  
in memory locations 0-9. S=m may be placed anywhere in the dial string;  
for example, AT D2345S=2 dials 2345 and the number is stored in  
memory location 2.  
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Modem 34336  
• H — Telephone Switch Hook. The H command (on-hook) is used to  
terminate a call. (On-hook corresponds to off-line.) H may also alternate  
between voice and data transmission during the same call (if your  
communication software supports this capability).  
The H1 command (off-hook) activates the telephone line relay, causing  
a dial tone to be sent after a 2-second delay. For most purposes the  
command is not necessary, since the switch hook is automatically  
activated when the Modem originates or answers a call.  
• L — Link. The L dial modifier is used to link one phone number to  
another. One number can be an alternate number to be dialed if a  
connection is not made to the primary number. The L parameter must  
be used after a phone number, and before a carriage return or period.  
A number is used after L to specify the memory address (0-9) containing  
the number to be linked to the first number. See the command below.  
AT D 555-1212 L5  
NOTE  
L may also be used in V.25 bis mode with the CRN command (instead of  
AT D), in both Dumb mode and 208 operation. In Dumb mode or 208  
operation, L is stored via the PHONE screen. In all cases, L is used in  
the same way and has the same function as described above (except that  
AT D is not used).  
Two or more addresses may be linked in a cyclic fashion to alternate  
dialing until a connection is established:  
Contents of cell 0: 555-1212 L1  
Contents of cell 1: 444-1234 L2  
Contents of cell 2: 888-5555 L0  
With the cells loaded as shown above, if the command AT DS=0 is issued,  
the autodialer goes to cell 0 and dials the number stored there. If unable  
to connect, the L1 command stored in cell 0 directs the autodialer to dial  
the number in cell 1. The L2 stored in cell 1 directs the autodialer to cell  
2 (assuming a connection cannot be made), and the L0 command stored  
in cell 2 directs the autodialer back to cell 0. The numbers are dialed in  
a loop until a connection is established or until 10 calls are attempted.  
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5.0 Hayes Emulation Mode  
• O — Forced On-Line. For asynchronous operation only. When the  
modem is on-line, you can return to the command state by entering  
the escape code (+++). After the desired command is executed, use the  
O command to force the modem from the command state to the on-line  
state.  
• P — Pulse Dial. The P command instructs the modem to pulse dial. It  
can be entered anywhere in the dialing string: AT P5551212; or it can  
be entered alone, followed by a carriage return, AT P, in which case all  
subsequent telephone numbers are pulse dialed. If the dial command  
does not specify which dialing mode to use, the modem defaults to the  
last mode specified.  
S= - Modify S Register. This command is used to write information to  
a specified S register. The syntax is Sr=n, where r is the number of the  
register to be modified and n is the value to be written to it; for example:  
AT S7=30  
This command would change the value of register S7 to 30. If you enter  
just =5, the auto-dialer changes the value of the last register used to 5.  
More information on S registers is included in Section 5.3.  
S? — Read S Register. This command instructs the autodialer to read  
the contents of the specified S register. The syntax is Sr?, where r specifies  
the register to be read. For example, S7? reads the value of register S7.  
The value is displayed on the computer or terminal monitor. If you enter  
? by itself, the autodialer displays the value of the last register used; if =  
is entered by itself, the autodialer displays the number of the last register  
used (e.g., S2). For information on how to interpret S register values,  
see Table 5-3.  
T — Tone Dialing. This command causes a telephone number in the dial  
command string to be dialed using tone signals. (See the P command  
above for additional information.)  
W — Wait For Dial Tone. The W command (or colon) is used in a dial  
string to instruct the Modem to wait for a dial tone before proceeding.  
Adjust the wait time (default, 30 seconds) by changing the value in  
register S7. If no dial tone is detected within the specified time, the  
Modem hangs up and gives a NO DIALTONE result code (if the result  
code is enabled by the X command).  
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Modem 34336  
• Z —Recall Stored User Profile. The Z command resets the modem and  
recalls a profile of the modem configuration settings previously saved  
using the &W command. The profile is designated as profile 0 or  
profile 1 when it is saved using the &W command.  
, —Pause. A comma causes the modem to pause for 2 seconds (or time  
specified in register S8) before processing the next character in a dial  
string or command. The Pause command is used to place an outside call  
through a PBX switchboard, where 9 must be dialed to gain outside  
access—the pause allows time for the dial tone to occur before the  
modem dials the number:  
AT D9,3331234  
Similarly, a comma may be used to cause the Modem to wait for a second  
dial tone before beginning to dial a telephone number. Use multiple  
commas to increase the pause time.  
; — Forced Command State. A semicolon placed at the end of a dial  
command causes the Modem to return to the command state after  
dialing without disconnecting.  
The following examples illustrate how the ; command is used:  
The first example is a banking transaction. The command AT D333-1234;  
dials the bank’s phone number and returns the Modem to the command  
state. After the OK prompt is displayed on the DTE, the command AT D  
T 0901# is entered. The command transmits the identification number  
0901 to the bank, and again returns the Modem to the command state.  
An account number and other data may be transmitted in the same way.  
The second example illustrates one method of autodialing. Enter a dial  
string that ends with a semicolon—for example, AT DT9, 3331234;  
During the ring signal or when the call is answered, pick up the phone  
and enter AT H. You may then use a telephone connected to the Modem  
for voice communication.  
Wait For Silence Before Dialing. The @ command is used to gain access  
to a system without a dial tone. It tells the modem to wait for 30 seconds  
(or the time specified by register S7) for one or more rings followed by 5  
seconds of silence before processing the next symbol in the dial string.  
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5.0 Hayes Emulation Mode  
! — Initiate Flash. The ! command causes the Modem to go on-hook for  
1/2 second. The command has the same effect as holding the switch-hook  
button on your telephone down for 1/2 second. Some PBX systems use a  
flash to transfer calls.  
&F — Recall Factory Configuration. The &F command restores the  
Modem to its original factory configuration, using data stored in ROM.  
However, the change is not permanent. If the Modem is turned off or  
reset, the recalled configuration is replaced with the default stored  
profile. (See &Y command.)  
&V — View Active Configuration, etc. This command displays the active  
modem configuration, user profiles stored using the &W command, and  
phone numbers stored using the &Z command. When &V is invoked,  
the DTE displays the configuration commands last issued, including  
parameters used, and the values currently stored in the S registers. The  
&V command should be issued as the last command on a line.  
• &W — Write Profile To Memory. The &W command saves the  
storable parameters of the Modem’s active configuration by writing the  
configuration profile to non-volatile memory. By selecting either &W0 or  
&W1, two different user profiles can be saved (profile 0 or 1). One  
of these profiles is automatically restored whenever the modem  
is powered on or when the Z command is issued. (See &Y and Z  
commands.)  
The &W command cannot be used to write changes to the user profiles if  
the Modem’s front panel is disabled with the Front Panel Control option.  
The parameters listed below cannot be stored—all are set by changing S  
register values (as indicated in Table 5-3):  
Backspace character (ASCII 08)  
Carrier-detect response time  
Carriage-return character (ASCII 13)  
DTMF tone duration  
DTR detection  
Escape-sequence character (ASCII 43)  
Escape-sequence guard time  
Line-feed character (ASCII 10)  
Lost-carrier-until-hangup time  
Pause duration (effected by comma)  
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Modem 34336  
Ring count  
Wait time before blind dialing  
Wait time for carrier/dial tone  
In addition, the &W command does not save stored phone numbers.  
&Z — Store Telephone Number. The &Z command is used to store a  
telephone number dialed using the DS (dial stored number) command.  
The syntax is &Zm=n, where m specifies the memory location in which  
the phone number or dial string is stored and n is the number or dial  
string to be stored. For example, AT &Z5=T 1 (301) 555-1212 stores  
the specified number at memory location 5. Ten memory locations are  
available—0-9.  
For pulse dialing, digits 0 through 9 can be stored. For tone dialing,  
0 through 9, A through D, #, and * can be stored. The dial-command  
modifiers listed in Section 5.1.2 can also be stored.  
Each memory cell can hold a maximum of 25 digits. Cells 1 through 9  
automatically expand to the next empty cell if loaded with more than 25  
digits. Even if a stored number is continued to another cell, the maximum  
number of characters that can be stored is 36. If more than 36 characters  
are included in a dial string, the command is ignored. A cell cannot hold  
a number unless it is empty. Only cell 0 can be accessed from the  
Modem’s front panel (via the PHONE LCD screen).  
• \S — View Status Of V.42-Related Configuration. The \S command  
displays the active V.42 error correction configuration, stored V.42  
profiles, and certain other data not displayed by the &V command.  
5.3 S Registers  
The Modem includes 28 registers (S0-S27) that are used to control specific  
modem operations in Hayes mode only. Each register holds a value serving  
as a specific operating instruction for the modem. Several of the S registers  
affect how the previously described commands are executed.  
The functions of the registers intended for user access are explained below  
and summarized in Table 5-3.  
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5.0 Hayes Emulation Mode  
5.3.1 READING AND SETTING REGISTERS  
Use the S command to read the value of a register or to change its value.  
To read the current value of a register, use the command S?, where the  
number of the register is specified between the S and the ?—for example, S9?.  
The decimal value of the register contents is displayed. You may read multiple  
registers. For example, if you wish to read the current value in registers S0  
and S7, enter the following command.  
AT S0? S7?  
A typical response might be 001, 030, OK, meaning the values stored in  
registers S0 and S7 are 1 and 30, respectively.  
To set or change a parameter, use the command S=, where the number of the  
register follows S and a value between 0 and 255 (the range of values that can  
be assigned to the registers) follows the equal sign:  
AT S0=5  
The above command changes the value stored in S0 to 5.  
The S command can also be used without ? or = to point to a register that will  
be read from or written to without being specified. To illustrate this, if you  
enter the following command, a pointer is set to the address of register S7.  
AT S7  
As long as no other S command is entered, the register value can be  
requested at any time without specifying the number. If you enter AT ? the  
modem displays the current value in the S7 register. Similarly, if you enter  
AT=8 the modem changes the value in the S7 register to 8.  
5.3.2 S REGISTER FUNCTIONS  
This section describes the function of each S register. Table 5-3 lists the range  
of possible parameters and the default value for each S register.  
S0 — Ring To Answer On. The value in this register determines on what  
ring (first, second, third, etc.) the modem answers. Setting S0 to 0  
disables auto-answer.  
• S1 — Ring Count. Register S1 counts the number of ring signals for each  
incoming call. If more than 8 seconds pass since the last ring, S1 is cleared  
to zero.  
• S2 — Escape-Code Character. The escape code is effective for  
asynchronous operation only. Values greater than 127-completely disable  
escape code detection and prevent you from issuing a hang-up command.  
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S3 — Carriage Return. Register S3 is effective for asynchronous operation  
only. Normally, the ASCII carriage-return value, 13, is used.  
S4 — Line Feed. This register is effective for asynchronous operation only.  
The line-feed character follows the carriage return only when word result  
codes are selected (command V1). Line feed can be changed to a null but  
cannot be totally disabled.  
• S5 — Backspace. This register is effective for asynchronous operation only.  
The value in S5 defines the backspace character. Do not use values  
between 33 and 126.  
S6 — Blind-Dialing Wait Time. The value in S6 determines how long the  
Modem waits after picking up the telephone line (going off-hook) before  
beginning to dial. If S6 is set for less than 2 seconds, the modem waits 2  
seconds before dialing. If the X2 or X4 command is in effect, dial-tone  
detection is enabled and blind dialing is disabled, meaning the value in  
S6 has no effect.  
• S7 — Carrier/Dial-Tone Wait Time. This register controls two wait times—  
wait time for carrier and, if W is included in the dial string, wait time for  
dial tone (or wait time for silence if @ is used).  
• S8 — Pause Time. Register S8 controls the pause time effected by a  
comma in a dial string or other command line.  
• S9 — Carrier Detect Response Time. Register S9 determines how long a  
carrier tone must be present for the Modem to recognize the tone and  
indicate a carrier detect. (The time required for the absence of a carrier  
tone to be recognized is fixed at 0.5 seconds.)  
• S10 — Loss Of Carrier Delay. The value in register S10 determines the  
length of the delay from the occurrence of a loss of carrier until the  
Modem hangs up the telephone line. A value of 255 disables the Modem’s  
carrier disconnect option (and line-current disconnect option), meaning  
the Modem will not hang up in the absence of carrier or line current.  
• S11 — Tones. This register sets the spacing of tones used for dialing. The  
rate is slowed by increasing the value of S11 to the maximum value, 255.  
This register has no effect on pulse dialing, which is fixed at 10 pulses  
per second.  
• S12 — Guard Time. This register is effective for asynchronous operation  
only. The escape guard-time delay is required immediately before and  
after entering the escape code; therefore, the three escape-code  
characters must be entered within the guard time delay of each other.  
The unit for this register is 1/50 second (or 20 ms), meaning the default  
value of 50 equals 1 second.  
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5.0 Hayes Emulation Mode  
If the guard time is zero, timing is not a factor. The three escape  
characters can occur with any timing relationship, but they must be  
consecutive. Be cautious when assigning small guard times. You may not  
be able to enter three characters fast enough, especially if the guard time  
is less than the time required to transmit one character at the current  
transmission rate.  
• S18 — Diagnostic Timer. The value in register S18 determines how long  
a diagnostic test runs. For example, if S18 is set to 120, the test (activated  
by one of the &T commands) runs for 120 seconds. If S18 is set to zero  
(the default), the test timer is disabled and the test runs indefinitely. To  
terminate a test when the test timer is disabled, use the command &T0,  
or reset the modem. Register S18 is set to zero on powerup, or by the  
command AT Z or AT S18=0.  
• S25 — Delay To DTR. The effect of the value stored in register S25  
is dependent on the operating mode, as explained below.  
Synchronous mode 1 — Before the Modem examines the state of DTR,  
a delay occurs after a call is established. The duration of the delay is the  
value specified in S25 (in seconds). This allows the operator time to  
disconnect the Modem from an asynchronous data terminal and attach  
it to a synchronous terminal without forcing the Modem back into the  
command state.  
Asynchronous mode and synchronous modes 1 and 3 — A change in DTR  
(ON or OFF) lasting for less than the value in register S25 (in hundredths  
of a second) is ignored by the Modem.  
• S26 — RTS To CTS Delay Interval. This register affects synchronous  
operation only. With the command &R0 in effect, CTS is turned on in  
response to an OFF-to-ON transition of RTS from the local DTE—after  
the delay specified by the value in register S26, but only if the Modem is  
on-line and ready to receive synchronous data.  
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Modem 34336  
5.4 Selecting Options In Hayes Mode  
In Hayes mode, options may be selected by using one of the following:  
• AT commands (Table 5-1)  
• The front panel  
• The Summary Setup feature  
The easiest way to change options in Hayes mode is to use the AT commands  
listed in Table 5-1 or the Modem’s front panel.  
The following guidelines apply to option selection in Hayes mode:  
• If an option is changed using an AT command, the change is effective  
for Hayes mode only, unless option changes are saved to memory.  
If you change an option using an AT command, and then switch to a  
different mode without saving the change, the front panel display LCD  
remains unaffected.  
• The effect of option changes made using the Summary Setup feature  
depends on which user profile (0 or 1) is active. See Section 5.4.1.  
5.4.1 SAVING OPTION SELECTIONS  
Changes made to option settings cease to be effective if power is removed  
from the Modem or if a factory reset occurs—unless the Modem's  
configuration is saved to nonvolatile memory. The storable parameters of  
the Modem’s configuration can be saved to user profile 0 or 1 using the &W  
command (&W0 or &W1). Upon powerup, the Modem recalls either profile  
0 or profile 1, depending on which is designated as the default profile.  
(The &Y command is used to designate the default profile.) The Modem  
is shipped from the factory with profile 0 as the default profile.  
As explained in the following sections, the Modem is programmed to treat  
profile 0 and profile 1 differently. It is recommended that you use profile  
0 for your standard configuration and make it the default profile (&Y0).  
Profile 1 is intended for storing an alternate configuration if you need one  
(e.g., an alternate application). To view the contents of the user profiles,  
use the &V and \S commands.  
5.4.2 PROFILE  
0
AND PROFILE  
1
User Profile 0 is linked to the Modem’s front panel (i.e., selections made  
using the front panel LCD).  
• If you make option changes using the front panel, the option changes for  
which there are associated Hayes commands are saved to profile 0 when  
you exit the SETUP menu.  
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5.0 Hayes Emulation Mode  
• If profile 0 is recalled as the active configuration, the LCD screens reflect  
the profile 0 configuration.  
• If profile 0 is changed by means of Hayes commands or via the Summary  
Setup feature and then saved, the changes made are reflected on the  
LCD and are effective for all modes.  
If you make option changes from the front panel without exiting the SETUP  
menu, and then make option changes using Hayes commands and use the  
&W command to save them to profile 0, the changes saved to profile 0  
override the front-panel selections.  
User Profile 1 is not linked to the front panel.  
• Option changes made from the front panel are not saved to profile 1.  
(Profile 1 can be changed only by using Hayes commands or the  
Summary Setup feature.)  
• If profile 1 is recalled as the active configuration, the LCD screens are not  
affected. When profile 1 is active, it is possible for the LCD to display an  
option setting not reflecting the setting currently in effect.  
• If profile 1 is changed by means of Hayes commands or via the Summary  
Setup feature, the changes are not reflected on the LCD and only affect  
Hayes mode operation.  
If profile 1 is being used as the active configuration, the options marked  
with an asterisk (*) in Table 5-1 should be controlled either with the AT  
commands listed in Table 5-1 or using the Summary Setup feature described  
in Appendix C. When Profile 1 is active, these options can be changed via  
the front-panel LCD, but the changes are effective only for Hayes mode  
operation. However, if Profile 0 is subsequently recalled as the active  
configuration, the changes are effective at that time.  
5.5 Hayes Mode Reference Tables  
Table 5-1 lists the Hayes compatible commands used with the Modem.  
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Modem 34336  
Table 5-1. Hayes Compatible Commands.  
COMMAND  
FUNCTION/EXPLANATION  
A
Quick Answer  
No parameters.  
A/  
Repeat Previous Command  
No parameters.  
B
B0  
B1  
Bell/CCITT Compatibility Mode *  
Selects CCITT V.22 mode.  
Selects Bell 212A mode.  
C1  
Modem displays OK; command has no other effect.  
This response instead of ERROR maintains a  
degree of compatibility with older modems  
supporting this command.  
D
Originate Mode For Dialing  
No parameters.  
DS  
Dial Stored Number  
Parameters are 0-9 (available memory locations).  
E
E0  
E1  
Echo  
No echo.  
Echoes all characters back to terminal screen when  
using a full-duplex terminal and in local command  
mode.  
F1  
Modem displays OK. Command has no other effect  
unless V.22 bis/V.22/ V.21/V.23 fallback operation  
is enabled.  
H
Telephone Switch Hook  
On-hook (hang up).  
Off-hook.  
H0  
H1 or H2  
Default settings (where applicable) are in bold face.  
* If user profile 1 is active, options are controlled (for Hayes mode  
operation) by given commands or Summary Setup. Do not change via  
front panel (except via Summary Setup).  
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5.0 Hayes Emulation Mode  
Table 5-1 (continued). Hayes Compatible Commands.  
COMMAND  
FUNCTION/EXPLANATION  
I
I0  
I1  
Product Code Or Checksum  
Requests product code.  
Requests checksum for the Modem’s software. (Only a  
portion of the checksum displayed via the front panel is  
displayed in decimal format.)  
I2  
I3  
Requests verification of software checksum.  
Requests the following for each EPROM  
(programmable memory unit): chip, part and revision  
number; checksum.  
I4  
L
Reserved.  
Link Dial (L specifies LINK function when used as a  
dial command modifier.)  
L
Speaker Volume *  
Low speaker volume.  
Medium volume.  
High volume.  
L0 or L1  
L2  
L3  
M
Speaker Control *  
M0  
M1  
M2  
M3  
Speaker always OFF.  
Speaker ON until carrier is detected.  
Speaker always ON.  
Speaker OFF during dialing; otherwise ON until carrier  
is detected.  
O
O0  
O1  
Forced On-Line  
Forces Modem to on-line state.  
Forces Modem to on-line state and initiates equalizer  
retrain.  
P
Pulse Dial No parameters, but the default is T (for  
tone dial).  
Q
Send Result Code  
Q0  
Q1  
Q2  
Send result codes.  
Withhold result codes (quiet).  
Withhold result codes for incoming calls only (quiet  
answer).  
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Modem 34336  
Table 5-1 (continued). Hayes Compatible Commands.  
COMMAND  
FUNCTION/EXPLANATION  
S=  
Modify S Register  
Parameters are register and value to be written.  
S?  
T
Read S Register  
Parameter is the register number.  
Tone Dialing  
No parameters.  
V
V0  
V1  
Word/Digit Result Code  
Result codes are transmitted as digits.  
Result codes are transmitted as words.  
W
Wait For Dial Tone  
No parameters, but default wait time (register S7) is  
30 seconds.  
X
Select Result Code  
X0  
Selects basic result codes, 0-4. No speed indication;  
no busy or dial tone detect.  
X1  
Selects result codes 0-5, 10, 11, 13, 14, 15, and 18.  
Connection speed (up to 14,400 bps) indicated; no  
busy or dial tone detect.  
X2  
X3  
X4  
Selects result codes 0-6, 10, 11, 13, 14, 15, and 18.  
Same as X1 except dial tone detect is enabled.  
Selects result codes 0-5, 7, 10, 11, 13, 14, 15, and 18.  
Same as X1 except busy-signal detect is enabled.  
Selects all result codes. Connection speed (up to  
14,400 bps) indicated; busy-signal and dial-tone detect  
enabled.  
Note: Result code 8 is independent of the X command;  
it is displayed only when the @ dial modifier is used.  
Default settings (where applicable) are in bold face.  
* If user profile 1 is active, options are controlled (for Hayes mode  
operation) by given commands or Summary Setup. Do not change via  
front panel (except via Summary Setup).  
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5.0 Hayes Emulation Mode  
Table 5-1 (continued). Hayes Compatible Commands.  
COMMAND  
FUNCTION/EXPLANATION  
Y
Y0  
Y1  
Long-Space Disconnect*  
Disables long-space disconnect.  
Enables long-space disconnect.  
Z
Z0  
Z1  
Recall Stored User Profile  
Resets modem and recalls stored user profile 0.  
Resets modem and recalls stored user profile 1.  
, (comma)  
; (semicolon)  
@
Pause –– No parameters, but default pause time (in  
register S8) is two seconds.  
Forced Command State  
No parameters.  
Wait For Silence Before Dialing –– No parameters, but  
default wait time (register S7) is 30 seconds.  
! (exclamation) Initiate Flash  
No parameters  
&C  
Data Carrier Detect Control *  
&C0  
&C1  
&C2  
DCD always ON when DTR is present.  
DCD ON only in the presence of suitable data.  
DCD ON when DTR is present; then toggles off for  
50 ms upon disconnect.  
&D  
&D0  
&D2  
Data Terminal Ready Control *  
Ignore DTR.  
Go on-hook, assume command state and disable auto-  
answer upon DTR ON-to-OFF.  
Reinitialize in the event of DTR ON-to-OFF.  
&D3  
&F  
Recall Factory Configuration  
No parameters.  
&G  
Guard Tone Control *  
&G0  
&G1  
&G2  
Guard tone disabled.  
Enables 550 Hz guard tone.  
Enables 1800 Hz guard tone.  
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Modem 34336  
Table 5-1 (continued). Hayes Compatible Commands.  
COMMAND  
FUNCTION/EXPLANATION  
&J  
Modem displays OK result code; command has no  
other effect. (The Modem is configured for A/A1  
control or MI/MIC control via jumpers JP2 and JP3, as  
detailed in Appendix D.)  
&L  
Modem displays OK result code; command has no  
other effect. (The Modem is configured for leased line  
or dialup line operation via the front-panel QUICK  
SETUP and/or LINE TYPE screens.)  
&M  
&P  
Can be substituted for &Q.  
Modem displays OK result code; command has no  
other effect. (The pulse-dialing ratio is factory-set,  
depending on whether the modem is a U.S. or  
international model.)  
&Q  
&Q0  
&Q1  
Asynchronous/Synchronous Mode  
Asynchronous mode.  
Synchronous mode 1— Synchronous/asynchronous  
mode  
Synchronous mode 2—OFF-to-ON DTR causes  
Modem to automatically dial a stored number.  
&Q2  
&R  
RTS And CTS Options *  
&R0  
&R1  
&R2  
CTS follows RTS.  
CTS follows DTR from the DTE.  
CTS is on while the modem is on-line.  
&S  
Data Set Ready Control *  
&S0  
&S1  
&S2  
DSR always on.  
DSR operates according to RS-232 specification.  
Options DSR operation for a crossover connection.  
Default settings (where applicable) are in bold face.  
* If user profile 1 is active, options are controlled (for Hayes mode  
operation) by given commands or Summary Setup. Do not change via  
front panel (except via Summary Setup).  
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5.0 Hayes Emulation Mode  
Table 5-1 (continued). Hayes Compatible Commands.  
COMMAND  
FUNCTION/EXPLANATION  
&T  
Test Commands  
&T0  
Terminates a test in progress. &T0 must be the last  
command in a command line.  
&T1  
&T3  
&T4  
Initiates a local analog loopback test.  
Initiates a local digital loopback test.  
Allows the local modem to accept a request from the  
remote modem for a remote digital loopback test.  
Prevents the Modem from accepting a request from the  
remote modem for a remote digital loopback test.  
Initiates a remote digital loopback test.  
Initiates a remote digital loopback test self-test.  
Initiates a local analog loopback self-test.  
&T5  
&T6  
&T7  
&T8  
&V  
View Active Configuration, etc.  
&V0  
Displays modem configuration, user profiles and phone  
numbers stored in memory cells 0-5.  
Displays all stored phone numbers (contents of memory  
cells 0-9).  
&V1  
&W  
Write Profile To Memory  
Saves storable configuration parameters as  
user profile 0.  
Saves storable configuration parameters as  
user profile 1.  
&W0  
&W1  
&X  
Transmitter Clocking *  
&X0  
&X1  
&X2  
Selects internal clocking.  
Selects external clocking.  
Selects receive mode (slaved) clocking.  
&Y  
&Y0  
&Y1  
Default User Profile  
Stored user profile 0 will be recalled on powerup.  
Stored user profile 1 will be recalled on powerup.  
Default settings (where applicable) are in bold face.  
* If user profile 1 is active, options are controlled (for Hayes mode  
operation) by given commands or Summary Setup. Do not change via  
front panel (except via Summary Setup).  
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Modem 34336  
Table 5-1 (continued). Hayes Compatible Commands.  
COMMAND  
FUNCTION/EXPLANATION  
&Z  
Store Telephone Number  
Parameters are 0-9 (available memory locations).  
B
\B0  
\B1  
Buffer Mode/Speed Conversion * 1  
Disables speed conversion.  
Enables speed conversion. <$!B10>  
\C  
MNP Class (Limit) * 1  
\C1  
\C2  
\C3  
\C4  
\C5  
Limits operation to MNP class 1.  
Limits operation to MNP classes 1 and 2  
Limits operation to MNP classes 1 through 3.  
Limits operation to MNP classes 1 through 4.  
Limits operation to MNP classes 1 through 5.  
\D  
\D0  
\D1  
Dialing Message  
Disables DIALING message.  
Enables DIALING message.  
\F  
\F0  
\F1  
MNP Flyback Buffer * 1  
Enables flyback buffer.  
Disables flyback buffer.  
\K  
V.42 Break Handling * 1  
\K0  
\K1  
\K2  
\K3  
Selects normal break handling.  
Selects destructive/expedited break handling.  
Selects non-destructive/expedited break handling.  
Selects non-destructive/ non-expedited break handling.  
M
V.42 bis Operation *1  
\M0  
Enables V.42 bis operation (error correction with data  
compression).  
\M1  
Disables V.42 bis operation.  
1Option can be changed only when Modem is off-line.  
Default settings (where applicable) are in bold face.  
* If user profile 1 is active, options are controlled (for Hayes mode operation) by given  
commands or Summary Setup. Do not change via front panel (except via  
Summary Setup).  
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5.0 Hayes Emulation Mode  
Table 5-1(continued). Hayes Compatible Commands.  
COMMAND  
FUNCTION/EXPLANATION  
\N  
V.42 Mode * 1  
\N0  
\N1  
\N2  
\N3  
Disables error correction.  
Enables mandatory mode for error correction.  
Disables error correction.  
Enables automatic mode for error correction.  
\P  
V.42 Protocol * 1  
\P0  
\P1  
\P2  
Selects LAPM protocol only.  
Selects MNP protocol only.  
Selects LAPM/MNP protocol (MNP as alternate).  
\Q  
V.42 Flow Control * 1 Two parameters may be used  
(e.g., \Q0,1; \Q3,2 , etc.). First parameter specifies DCE-  
DTE flow; second (optional) specifies DTE-DCE flow control.  
None (no flow control).  
CTS on/off or RTS on/off (CTS for DCE-DTE flow  
control, RTS for DTE-DCE).  
0
1
2
DC1/DC2 flow control.  
3
DC1/DC3 flow control (default for DCE-DTE and  
DTE-DCE).  
\S  
View Status Of V.42-Related Configuration  
No parameters.  
\T  
Load Inactivity Timer  
\T0  
\Tn  
Disables inactivity timer.  
Sets inactivity timer to n minutes (where n = 0 to 60).  
\V  
V.42 Result Codes1  
\V0  
\V1  
Activates regular V.42 result codes.  
Activates extended V.42 result codes.  
\X  
\X0  
\X1  
V.42 Pass-Through Flow Control * 1  
Enables pass-through flow control.  
Disables pass-through flow control.  
NOTE: DTE speed and parity are set automatically. Auto-answer is enabled or disabled by S register S0.  
1Option can be changed only when Modem is off-line.Default settings (where applicable) are in bold face.  
* If user profile 1 is active, options are controlled (for Hayes mode operation) by given commands or  
Summary Setup. Do not change via front panel (except via Summary Setup).  
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Modem 34336  
Table 5-2. Hayes Mode Result Codes.  
DIGIT  
CODE  
WORD  
OK  
CODE MEANING  
0
1
Command line executed without errors.  
CONNECT  
Carrier detected at 0-300, 1200, or  
2400 bps (basic code set).  
2
RING  
Ringing signal detected (in answer mode).  
(When the Modem detects a ring, it  
sends a RING result code unless it is in  
the process of accepting a command.  
However, the Modem answers the call  
only if it is set for automatic answer or is  
given an A command.)  
3
4
NO CARRIER  
ERROR  
Carrier lost or never detected.  
Error in command line, invalid command,  
command line exceeds 40 characters, or  
invalid character format.  
5
6
7
8
CONNECT 1200 Carrier detected at 1200 bps.  
NO DIALTONE  
BUSY  
No dial tone detected.  
Busy signal detected.  
NO ANSWER  
No period of silence detected. This code  
appears only if @ (wait for silence before  
dialing) is included in the dial string.  
10  
11  
CONNECT 2400 Carrier detected at 2400 bps.  
CONNECT 1275 Modem is on-line in V.23 mode  
(1200/75 bps).  
13  
14  
CONNECT 12.0 Carrier detected at 12,000 bps.  
CONNECT 14.4 Carrier detected at 14,400 bps.  
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5.0 Hayes Emulation Mode  
Table 5-2 (continued). Hayes Mode Result Codes.  
DIGIT  
CODE  
WORD  
CODE MEANING  
15  
18  
20  
CONNECT 4800 Carrier detected at 4800 bps.  
CONNECT 9600 Carrier detected at 9600 bps.  
LINKING  
Modem is dialing numbers that are  
linked using the L (link) dial modifier.  
Note: Four additional word codes are BUFFER, MNP, V42, and V42 bis,  
followed by the DTE interface speed. These codes indicate if the Modem is  
in buffer, MNP or LAPM (V.42/V.42 bis) mode. The corresponding digit  
codes and speeds they indicate are listed below (with all speeds in bits per  
second):  
BUFFER:  
MNP:  
28=19200, 29=9600, 30=4800, 31=2400, 32=1200,  
33=600, 34=300, 35 -110, 53=38400  
36=19200, 37=9600, 38=4800, 39=2400, 40=1200,  
41=600, 42=300, 43 -110, 54=38400  
44=19200, 45=9600, 46=4800, 47=2400, 48 -1200,  
49=600, 50=300, 51=110, 52=38400  
55=38400, 56=19200, 57=9600, 58=4800, 59=2400,  
60=1200, 61=600, 62=300, 63=110  
V42:  
V42 bis:  
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Modem 34336  
Table 5-3. S Register Functions.  
(Only registers intended for user access are listed.)  
REGISTER RANGE UNITS  
DEFAULT DESCRIPTION  
S0  
S1  
S2  
S3  
S4  
S5  
S6  
0-255  
0-255  
0-127  
0-127  
0-127  
0-127  
2-255  
rings  
rings  
ASCII  
ASCII  
ASCII  
ASCII  
sec  
1
0
Ring to answer on  
Counts number of rings  
Escape-code character  
Carriage-return character  
Line-feed character  
43  
13  
10  
8
Backspace character  
2
Wait time before blind  
dialing  
S7  
1-60  
sec  
30  
Wait time for carrier or  
dial tone  
S8  
S9  
0-255  
1-255  
sec  
2
6
Pause time for comma  
1/10 sec  
Carrier-detect response  
time  
S10  
1-255  
1/10 sec  
14  
Delay time between loss  
of carrier and hang-up  
S11  
S12  
S18  
S25  
70-255  
0-255  
0-255  
0-255  
ms  
70  
50  
0
Tone spacing  
1/50 sec  
sec  
Escape code guard time  
Test timer  
sec or  
1/100 sec  
Delay to DTR1  
5
0
S26  
0-255  
1/100 sec  
RTS-to-CTS delay (half  
duplex)  
1Depends on mode; see previous section, S25 - DELAY TO DTR.  
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6.0 V.25 bis Autodialer  
6.0 V.25 bis Autodialer  
For international compatibility, the Modem can function as a V.25 bis  
autodialer. In V.25 bis mode, the Modem is compliant with CCITT  
recommendation V.25 bis—an internationally recognized standard for serial  
automatic call origination and answering.  
The V.25 bis autodialer uses the dialing command set defined by the V.25 bis  
recommendation. You can store and dial phone numbers from the DTE in  
both synchronous and asynchronous applications. You can dial numbers  
directly, or you can instruct the Modem to automatically dial a previously  
stored number.  
6.1 Enabling The V.25 bis Autodialer  
The V.25 bis autodialer can be enabled by either using the Quick Setup  
feature, or selecting one of the Dialer Mode options.  
QUICK SETUP  
Three Quick Setup configurations are available for 2-Wire Dial (V.25 bis).  
Selecting any of the three V.25 bis Quick Setups (via QUICK on SETUP  
screen 1) enables the V.25 bis autodialer and causes all modem options to be  
automatically set to a preset configuration. Each V.25 bis Quick Setup is  
suitable for a typical V.25 bis application, depending on the DTE to be used.  
To select a 2-Wire Dial (V.25 bis) Quick Setup, access QUICK SETUP screen  
2, 3, or 4 (for asynchronous; synchronous, character-oriented; or synchro-  
nous, bit-oriented operation) on the LCD, and then press push-button 2.  
After selecting the desired V.25 bis Quick Setup configuration, you can reset  
individual options to suit your application (see Chapter 2).  
In accordance with the CCITT V.25 bis recommendation, the Modem V.25 bis  
asynchronous Quick Setup sets the character length to 10 bits, including 1  
even parity bit. Both V.25 bis synchronous Quick Setups set the modem for  
odd parity. (For synchronous operation, the character length option setting  
has no effect.)  
DIALER MODE (DIAL V25BIS SCREEN)  
If you enable the V.25 bis autodialer using the Dialer Mode option, no other  
options are changed. Select DIALER from SETUP screen 2. Then, press the  
right arrow pushbutton to go to the DIAL V25 bis screen (screen 2). Select  
the V.25 bis data protocol appropriate for the DTE to be used: asynchronous  
(Asyn); synchronous, character-oriented (Syn_c); or synchronous, bit-  
oriented (Syn_b).  
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Modem 34336  
DTR DIALING IN V.25 BIS MODE  
An alternative to using the V.25bis CRS command to dial a stored number is  
to use the DTR dialing option. With DTR dialing enabled, the autodialer will  
dial the number stored in the phone cell displayed in the front-panel AUTO-  
DIAL screen when DTR goes high for at least 50 ms.  
To enable V.25 bis DTR dialing, sue the Summary Setup feature (see  
Appendix C) to change the parameter for V25 bis DTR dialing to 1. Do not  
select DTR dialing via the front panel DIALER screen; this will not enable  
DTR dialing for V.25 bis mode. V.25 bis DTR dialing will function only if  
the V25bis DTR dialing parameter is enabled (set to 1) and the V.25 bis  
autodialer is enabled.  
6.2 V.25 bis Autodialer Commands  
In asynchronous applications, V.25 bis commands are issued directly from  
the DTE keyboard or through communications software. In synchronous  
applications, the V.25 bis commands are used to facilitate computer-  
controlled communications.  
Punctuation and spaces may be used with V.25 bis commands for clarity,  
but they are not required. If used, they are ignored by the modem. One  
exception is the colon ( : ), which instructs the autodialer to wait for a  
dial tone.  
The V.25 bis commands are described below and are summarized  
in Table 6-1. See Table 6-3 for explanation of the codes displayed  
in response to commands.  
CIC — Connect Incoming Call. The CIC command instructs the  
autodialer to answer incoming calls. The effect is the same as enabling  
auto-answer on the modem’s front panel.  
CRN — Call Request, Number Provided (Syntax: CRN 5557979). By  
using the CRN command, you can dial a number directly from the DTE  
keyboard. Numbers from 0 through 9 can be dialed, and if tone dialing  
is enabled, the characters A, B, C, D, #, and * can also be dialed.  
The dialing parameters listed in Table 6-2 are used with the CRN  
command to specify how or when a number should be dialed. For  
example, the command line CRN :T3331234 instructs the autodialer  
to wait for a dial tone (:) and then tone-dial (T) the number 333-1234.  
• CRS — Call Request, Address Provided (Syntax: CRS 2). The CRS  
command allows you to dial a number simply by specifying its memory  
address. In the example given above, the autodialer dials the number  
stored in memory address 2. Store the number at the specified address  
using the PRN command (Table 6-1).  
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6.0 V.25 bis Autodialer  
DIC — Disregard Incoming Call. The DIC command instructs the  
autodialer not to answer an incoming call. The DIC command is  
cancelled when the CIC command is issued or auto-answer is enabled  
from the front panel.  
• PRN — Program Normal (Store Number)  
(Syntax: PRN<|>1;<|>5551212). The PRN command is used to store  
a number or dial string in a memory address location (cell) so it can  
be dialed later by specifying only the address. As shown above, PRN is  
followed by the memory location, a semicolon, and the phone number  
to be stored. After a number is stored, it can be dialed using the CRS  
command. You can store any of the characters listed in Table 6-2.  
Ten memory cells (0-9) are available for phone number storage. Each  
cell can hold a maximum of 25 characters, although cells 1 through 9  
automatically expand to the next empty cell if loaded with more than 25  
digits. Even if a stored number is continued to another cell, the maximum  
number of characters that can be stored is 36. You cannot store a number  
in a cell unless it is empty. To clear a cell, enter PRN and the address,  
without a number. Only cell 0 can be accessed from the modem’s front  
panel (via the PHONE LCD screen).  
RLN -— Request Stored Number(s). RLN is used to request a list of  
all stored numbers or to show the number stored in a specific memory  
address. RLN, used alone, requests a list of all stored numbers.  
The DTE display shows the stored numbers as follows:  
LSN 0;  
LSN 1;  
LSN 2;  
301 555 1234  
301 123 4567  
301 555 5555  
(and so on through memory address 9)  
If a memory address is specified after RLN, e.g., RLN 5, the DTE display  
shows only the number stored at the specified address.  
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Modem 34336  
Table 6-1. V.25 bis Autodialer Commands.  
FUNCTION  
COMMAND  
CIC  
Connect incoming call.  
CRN n  
Call request—dial number (n) entered on DTE  
keyboard.  
CRS m  
Call request—dial number stored in specified  
memory address (m).  
DIC  
Disregard incoming call.  
PRN m n  
Program normal—store number or dial string n in  
memory address m.  
RHA  
Switch to Hayes dialing mode (also resets modem  
configuration).  
RLN  
Request list of all stored numbers.  
RLN m  
Request to see number stored at address m.  
n — represents a number to be dialed or stored (e.g., 5557979).  
m — represents a memory address where a number is stored (0-9).  
A comma ( , ) can be included in a dial string to effect a pause.  
A colon ( : ) can be included to instruct the autodialer to wait for a dial tone  
before proceeding.  
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6.0 V.25 bis Autodialer  
Table 6-2. V.25 bis Dialing Parameters.  
(Table also applies to Dumb mode and Bell 208 operation)  
Characters that can be dialed: 0—9  
Can only be tone dialed:  
A, B, C, D, #, and *  
L
Links a phone number to another  
number to be dialed as an alternate  
when the primary number is busy or  
does not answer. See L - LINK in  
Section 5.2.  
P
Sets pulse-dialing mode.  
Sets tone-dialing mode.  
T
W or : (colon)  
Wait 30 seconds for dial tone before  
proceeding.  
[CR] or .  
(carriage return  
or period)  
Required at end of dial command line.  
[CR] is sent from DTE keyboard.  
Dumb/208 mode only: Period has  
same function, but may be entered via  
front panel (PHONE LCD screen).  
, (comma)  
or <  
Pause before processing next  
character in dial string.  
L, P, T, and W may be entered as upper- or lower-case letters. Spaces or  
hyphens (-) may be used as separators for clarity; they have no effect.  
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Modem 34336  
6.3 Dialing Parameters  
Table 6-2 lists dialing parameters you can use with the CRN command  
to modify dialing operations.  
6.4 V.25 bis Result Codes  
Table 6-3 explains the result codes, or responses, that are displayed  
on the DTE monitor during V.25 bis operation.  
6.5 DTR Dialing In V.25 bis Mode  
An alternative to using the CRS command to dial a stored number is to use  
the DTR dialing option. With DTR dialing enabled, the autodialer dials the  
number stored in memory address 0 when DTR goes high for at least 50 ms.  
To enable V.25 bis DTR dialing, use the Summary Setup feature (as described  
in Appendix C) to change the parameter for V.25 bis DTR dialing to 0. Do  
not select DTR dialing via the front-panel DIALER screen; it does not enable  
DTR dialing for V.25 bis mode.  
Table 6-3. V.25 bis Result Codes.  
CODE  
CFI AB  
CFI ET  
CFI NS  
MEANING  
Call failure; absence of carrier.  
Call failure because of busy signal.  
Call failure; call request specified an address that  
does not contain a stored number.  
CFI NT  
INC  
Call failure; no answer tone detected.  
Incoming call.  
INV  
Invalid command entry.  
LSN  
List of stored numbers; is followed by memory  
address, stored number, next memory address, next  
stored number, etc.  
VAL  
Command accepted; waiting for next command.  
A semicolon may be used to separate parameters, e.g., LSN 4;5559797.  
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7.0 Diagnostics  
7.0 Diagnostics  
The troubleshooting information in this chapter applies to all Modem  
applications (all dialup and leased line modes), unless specifically stated  
otherwise.  
For specific test procedures, turn to one of the following sections in this chapter:  
Section 7.7 — Local Modem Diagnostics  
Section 7.8 — Remote Diagnostics  
7.1 When And Why To Test  
If you experience communications difficulties, you should try to isolate the  
defective component in your communications system. You must first identify  
the symptoms and scope of the problem. Then, perform a physical inspection  
of all units and connections in the system. Finally, conduct diagnostic tests.  
Very often the diagnostic testing capabilities of the Modem help identify  
the specific faulty component, whether it is the modem, the DTE, or the  
telephone line.  
7.2 Symptoms and Scope of The Problem  
To isolate the problem, carefully consider each of the following questions:  
• When did the problem begin?  
• What is malfunctioning? Try to isolate the component or components  
of your system that are malfunctioning.  
• Has there been a recent change in the system?  
• Has the modem been reconfigured?  
You can quickly find out if the modem is reconfigured by checking the  
checksum shown in the SUMMARY screen (accessed via SETUP screen 6)  
and comparing it with the checksum displayed when the modem was  
operating properly. If the checksum is different from the original, one or  
more option settings are changed. If you previously recorded the number  
strings (i.e., option parameters) displayed in the setups screens, you can  
determine which option settings are changed (by comparing the previous  
and current option parameters).  
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Modem 34336  
7.3 Physical Inspection  
The next step in isolating a defective component is inspecting the system.  
If you can trace the problem to a specific site, examine that site. Check the  
installation of the modem and DTE. Are all cables in good condition and  
fully connected? Are all components in the system receiving power? Inspect  
the system as thoroughly as possible.  
7.4 Overview Of Modem Diagnostics  
Once you identify the symptoms and conduct a physical inspection of the sites  
in question, you can use diagnostic monitoring and testing to further isolate  
the problem. The Modem is equipped with diagnostic capabilities enabling  
you to locate faults quickly and easily. The diagnostic features of the Modem  
fall into two categories — local and remote — as listed below.There are six  
types of local modem diagnostics:  
• Analog loopback (ALB)  
• Analog loopback self-test (ALBST, or ST)  
• Analog loopback self-test with errors (ST/E)  
• External analog loopback (ALBX)  
• External analog loopback self-test (ALXST)  
• Digital loopback (DLB)  
There are two types of remote diagnostics:  
• Remote digital loopback (RDL)  
• Remote digital loopback self-test (RDLST)  
The sequence in which you should conduct diagnostic tests depends upon the  
symptoms you identified, the availability of personnel at the remote site, and  
external test equipment. The self-test pattern generator and pattern detector  
built into the Modem alleviate the requirement for external test equipment.  
With the non-self tests, use either a standard DTE or an external bit error rate  
test (BERT) to generate test data and compare it with received data.  
Because more transmission errors occur at higher speeds on marginal  
transmission facilities, begin testing at the highest available speed. If errors  
occur, reduce the speed and try again. If you cannot correct the problem,  
contact your supplier.  
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7.0 Diagnostics  
7.5 How to Select and Activate Tests  
7.5.1 FRONT-PANEL CONTROL  
Tests are accessed and activated in the same way options are selected: by using  
the LCD and front panel pushbuttons (as explained in Chapter 3). To find  
the LCD screen for a specific test, refer to the LCD flow chart (Diagnostic  
And Control Functions) at the end of this manual. Once you access the  
screen for a specific test, press pushbutton 1 to begin the test (select ON). A  
test status screen is automatically displayed. To deactivate a test, press the  
ENT pushbutton and then pushbutton 3. (The ENT button cannot be used to  
exit the text screen until the test is deactivated.)  
NOTE  
For valid test results, error correction must be disabled before diagnostic  
tests are run. To disable error correction, set the V.42 Mode option to  
OFF.  
7.5.2 RUNNING TESTS IN HAYES MODE  
In Hayes emulation mode only, most of the diagnostic tests available on the  
Modem can be activated via the DTE keyboard using the &T commands listed  
in Chapter 5. To set the duration of a test, assign a value to register S18. For  
example, AT S18=30 sets the test time to 30 seconds. The command &TO  
terminates a test. For further information, see Section 5.2.  
7.5.3 REMOTE TEST CONTROL  
You can configure the Modem to ignore or accept requests from remote  
modems to initiate tests on your Modem. To access the remote-test control  
option, select TEST from SETUP screen 4. Then, select RMT from the TEST  
OPTIONS screen. From the REMOTE TEST screen, select ENABLE to allow  
remote test initiation or DISABLE to refuse remote test requests.  
7.6 Diagnostic Monitoring: Status Screens  
To obtain additional information about the status of the communications  
system, observe the status screens described in the following sections. To  
view these screens, push the ENT button until the EIA status screen appears.  
Use the right arrow pushbutton to advance to other status screens.  
7.6.1 EIA STATUS SCREEN  
The EIA status screen indicates the  
operational status of the modem and  
D TR MR RS CS TD  
the condition of certain EIA RS-232  
leads. The abbreviations that appear  
are identified below; however, only  
a few of these abbreviations are  
9600 TM ER CD RD  
1
2
3
displayed during actual operation.  
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D = Dial line occupied  
R = Ringing (R appears in same position as D.)  
S = Connection secured by security handshake (S appears in same position  
as D. S and D may flash alternately.)  
TR = Data Terminal Ready  
MR = Data Set Ready  
RS = Request to Send  
CS = Clear to Send  
TD = Transmit Data  
9600, 4800, etc. = Data speed  
(idle—the Modem is off-line—or H-01, H-14, etc., may also be displayed  
in the data speed position; see following text.)  
TM = Test mode  
ER = Error (poor signal quality)  
CD = Carrier Detect  
RD = Receive Data  
When two modems establish a connection, they engage in an exchange  
known as a handshake. While a handshake is taking place, the Modem  
displays several codes ranging from H-01 to H-28 in the lower left corner  
of the EIA status screen. A handshake lasts for up to 12 seconds and is  
accompanied by various audible tones.  
By pressing pushbutton 1 while the EIA status screen is displayed, you can  
access two checksum screens, one for the Modem’s main circuit board and  
one for the data pump. The checksums provide data intended for use by  
servicing personnel. The checksum screens also show the software revision  
levels (which are also shown on the power-on screen).  
7.6.2 OTHER STATUS SCREENS  
Quality Screen. Displays the quality of the received signal carrier as  
a numeric value and as a horizontal bar graph. A low numeric value  
indicates good signal quality. The best possible signal quality is indicated  
when the bar graph extends all the way to the right edge of the LCD.  
Line Levels Screen. Shows the preset level of the transmit signal (TX)  
and the measured level of the receive signal (RX).  
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7.0 Diagnostics  
The RX value is the local receive level of the incoming signal. The receive  
level range of measurement is from 0 to -43 dBm in 1.5-dBm increments.  
If the signal level is less than the carrier detect threshold, "<CD" is  
displayed.  
Echo Characteristics Screen. Displays the characteristics of the echo  
portion of the receive signal. Specifically, it shows milliseconds of delay  
and the offset frequency in Hertz.  
Channel Frequency Offset. Displays the frequency offset of the receive  
signal in Hertz.  
Throughput Screen. Functions only if error correction is enabled.  
It shows the rate (in bits per second) at which the Modem is accepting  
charatcters from the DTE.  
Packet Screen. The packet screen functions only when error correction  
is enabled. It has three components, as explained below.  
Size. Shows size of data packets (MNP) or blocks (V.42/V.42 bis)  
currently being transmitted. MNP uses shorter packets to transmit  
through noisy lines and longer packets (allowing greater throughput)  
when line conditions are good. The maximum MNP packet size is 64  
(MNP classes 1-3) or 256 characters (MNP classes 4 and 5). The block  
size for V.42/V.42 bis is fixed at 128 characters.  
Transmitted (TX). Number of packets or blocks transmitted since the  
connection was established.  
Errors (ER). Number of retransmissions (retransmitted because of data  
errors) since the connection was established.  
Mode and Rate Screen. Shows the following data:  
Mode. Below MODE, the screen indicates the error correction status:  
NORMAL — Error correction and buffer mode are both inactive.  
V42 — V.42 error correction (LAPM) is active.  
V42bis — V.42 bis error correction (LAPM with data compression)  
is active.  
MNP 01 to MNP 05 — MNP error correction is active.  
BUFFER — Buffer mode is active.  
OFFLINE — Modem is off-line.  
Rate. Shows the data rate of the DTE.  
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Modem 34336  
7.7 Local Modem Diagnostics  
Local modem diagnostics are for testing the Modem and its adjoining system.  
The tests are accessed from the main menu and are easily performed if the  
Modem is attached to DTE or an external BERT.  
7.7.1 ANALOG LOOPBACK (ALB) TEST  
Analog loopback testing allows you to test the local modem and its associated  
terminal independently from the telephone interface and the remote  
modem. Figure 7-1 shows the connections automatically made during the  
test.  
TRANSMITTER  
DATA TERMINAL EQUIPMENT  
(DTE) AT LOCAL SITE  
RECEIVER  
LOCAL MODEM  
Figure 7-1. Analog Loopback Test.  
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7.0 Diagnostics  
In Hayes emulation mode only, initiate the ALB test using the command &T1  
(preceded by AT). In any mode, initiate the ALB test using the modem’s  
front panel controls, explained in the following paragraphs.  
Make sure the modem is idle, the data rate is the same as the DTE’s data rate,  
and the DTR circuit is on. (If TR is present on the EIA status screen, the DTR  
circuit is on.)  
From the second page of the LCD MAIN MENU, select TEST. TEST takes you  
to screen 1 of the LOCAL TEST menu, where ALB is displayed as one of the  
test selections. Select ALB.  
The ANALOG LOOPBACK screen is displayed, with ON and OFF as the  
possible selections.  
Select ON to activate the test. In general, the "DSR during ALB test option"  
discussed in Chapter 3 should be left ON (default selection) to avoid  
disrupting the DTE and DTE software operations.  
The EIA status screen is displayed while the test is being conducted. Make  
sure that test data is being generated. Watch for data errors. By transmitting  
test data and comparing it with the received copy, you can make sure the DTE  
and modem are both working.  
To end the test, press the ENT pushbutton to return to the ANALOG  
LOOPBACK screen, and then select OFF.  
7.7.2 ANALOG LOOPBACK SELF-TEST (ALBST)  
In the analog loopback self test, the modem is placed in analog loopback and  
data is sent and received by an internal 511-bit pattern generator and  
receiver. Therefore, no DTE or external BERT is necessary. Figure 7-2 shows  
the data flow for this test.  
In Hayes mode only, initiate the ALBST using the command &T8 (preceded  
by AT). In any mode, initiate the ALBST using the modem’s front-panel  
controls, as follows:  
From page 2 of the LCD MAIN MENU, select TEST. This takes you to screen  
1 of the LOCAL TEST menu, where ALBST is visible as one of the selections.  
Select ALBST.  
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Modem 34336  
829 Block  
External loopback  
(leased line)  
Transmitter  
Receiver  
Pattern  
generator  
Pattern  
detector  
Figure 7-2. Analog Loopback Self-Test (ALBST).  
The SELFTEST screen is displayed, with ON and OFF as the possible  
selections. Select ON to activate the test. The EIA status screen is displayed  
while the test is being conducted. If ER is present on the front panel, data  
errors occurred. The ER indicator may flash on when the test is first started,  
but it should quickly go out and remain off until the end of the test.  
To end the test, press the ENT pushbutton to return to the SELFTEST screen.  
Then select OFF.  
7.7.3 ANALOG LOOPBACK SELF TEST WITH ERRORS (ST/E)  
In the analog loopback self test with errors, data is sent and received by an  
internal 511-bit pattern generator and receiver. No DTE or external BERT is  
necessary. This test differs from the ALBST in that errors are injected into the  
data flow every few seconds. The data flow is the same as that shown in Figure  
7-2 (the ALBST).  
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7.0 Diagnostics  
To run the test, go to the LCD MAIN MENU. From page 2 of the LCD MAIN  
MENU, select TEST. This takes you to screen 1 of the LOCAL TEST menu,  
where ST/E is visible as one of the selections. Select ST/E.  
The SELFTEST W/ERROR screen is displayed, with ON and OFF as the  
possible selections. Select ON to activate the test. The EIA status screen is  
displayed. The ER indicator should flash every few seconds, indicating that  
the pattern generator and detector are working. Errors are injected every few  
seconds. To end the test, press the ENT pushbutton to return to the  
SELFTEST W/ERROR screen. Then select OFF.  
7.7.4 EXTERNAL ANALOG LOOPBACK (ALBX) TEST  
The external analog loopback test is available forB.  
The ALBX test allows you to test the local modem and its associated terminal,  
and to verify the availability of the leased-line circuit. The test circuit does not  
include the remote modem. Figure 7-3 shows the connections automatically  
made during the ALBX test.  
829 Block  
External loopback  
(leased line)  
Receiver  
Data terminal  
Transmitter  
equipment (DTE)  
at local site  
Local modem  
Figure 7-3. External Analog Loopback Test (ALBX).  
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Modem 34336  
NOTE  
The ALBX test may result in errors or may fail altogether even where  
conditions are satisfactory for normal operation. The test channel  
presented to the modem during the ALBX test includes all impairments  
of both the inbound and outbound channels (ampli-tude distortion, delay  
distor-tion, noise, etc.). The main purpose of the ALBX test is to verify  
that the Modem is connected to the leased line and the leased-line circuit  
is complete. The test is not meant to assess the suitability of the leased  
line.  
Initiate the ALBX test using the Modem’s front-panel controls, as explained  
in the following paragraphs.  
Make sure the local modem is not in communication with the remote  
modem, the data rate is the same as the DTE’s data rate, and the DTR circuit  
is on. (If TR is present on the EIA status screen, the DTR circuit is on.)  
From the second page of the LCD MAIN MENU, select TEST. Go to the  
second page of the LOCAL TEST menu. Select ALBX.  
The ANALOG LOOP(EXT) screen is displayed, with ON and OFF as the  
possible selections.  
Select ON to activate the test. In general, the "DSR during ALB test" option  
discussed in Chapter 2 should be left ON (default selection) to avoid  
disrupting the DTE and DTE software operations.  
The EIA status screen is displayed while the test is being conducted. If no  
external loopback is present, the status screen displays an IDLE message. If a  
loopback is present, handshake sequence codes appear (H-01, etc.), followed  
by the modem speed. Ensure that test data is being generated and watch for  
data errors. By transmitting test data and comparing it with the received  
copy, the DTE and modem are checked for proper operation. During the  
ALBX test, RD (receive data) may appear on the status screen even though no  
data is being received.  
On a flat line, the Modem in ALBX test mode trains and remains running  
across the following range of signal loss: in V.32 mode, 0-51 dBm (0-52 dBm  
at 12,000 bps); for V.33 operation, 0-47 dBm; and for Bell 208A/B operation,  
0-37 dBm. If signal loss exceeds the limits, the test may not start or may be  
halted.  
During the ALBX test, the modem attempts to retrain upon loss of carrier.  
In switched carrier mode, the modem attempts to retrain upon loss of RTS.  
To end the test, press the ENT pushbutton to return to the ANALOG  
LOOP(EXT) screen. Then select OFF.  
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7.0 Diagnostics  
7.7.5 EXTERNAL ANALOG LOOPBACK SELF-TEST (ALXST)  
The external analog loopback self-test is available for 4-wire leased line mode  
only.  
The ALXST places the modem in analog loopback and causes data to be sent  
and received by an internal 511-bit pattern generator and receiver. No DTE  
or external BERT is necessary. As shown in Figure 7-4, the test circuit includes  
the leased lines (the external loopback).  
NOTE  
The ALXST may result in errors or may fail altogether even where  
conditions are satisfactory for normal operation. The test channel  
presented to the modem during the ALXST includes all impairments of  
both the inbound and outbound channels (amplitude distortion, delay  
distortion, noise, etc.). The main purpose of the ALXST is to verify that  
the modem is connected to the leased-line and the leased line circuit is  
complete. The test is not meant to assess the suitability of the leased  
line.  
TRANSMITTER  
RECEIVER  
PATTERN  
GENERATOR  
PATTERN  
DETECTOR  
Figure 7-4. External Analog Loopback Self Test (ALBST).  
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Modem 34336  
To initiate the ALXST, use the Modem’s front-panel controls to go to the  
LCD MAIN MENU. From page 2 of the LCD MAIN MENU, select TEST.  
Go to the second page of the LOCAL TEST menu. Select ALXST.  
The ANALOG ST (EXT) screen is displayed, with ON and OFF as the possible  
selections. Select ON to activate the test.  
The EIA status screen is displayed while the test is being conducted. If no  
external loopback is present, the status screen displays an IDLE message.  
If a loopback is present, handshake-sequence codes appear, followed by the  
modem speed. If "ER" is present on the front panel, data errors occurred.  
The ER indicator may flash on when the test is first turned on, but it should  
quickly go out and remain off until the end of the test.  
The information at the end of the previous section (for the ALBX test)  
concerning signal loss, loss of carrier, and loss of RTS also applies to the  
ALXST.  
To end the test, press the ENT pushbutton to return to the ANALOG ST  
(EXT) screen. Then select OFF.  
7.7.6 DIGITAL LOOPBACK TEST (DLB)  
Digital loopback testing determines the operational performance of the local  
modem, the remote modem, and the telephone line as a composite system.  
For the test, data must be sent and received at the remote modem. The test  
regenerates the data and loops it back to the remote modem. As with the ALB  
test, a comparison of the results of the DLB test indicates whether or not the  
DTE is performing satisfactorily. A comparison of the results of the ALB and  
DLB tests can help determine whether the modem or the telephone line is  
defective.  
In the DLB test, the data to be sent and received is originated and checked by  
the DTE or external BERT. Figure 7-5 shows the data flow for this test.  
In Hayes mode only, initiate the DLB test using the command &T3 (preceded  
by AT). In any mode, initiate the DLB test using the modem’s front-panel  
controls.  
From page 2 of the LCD MAIN MENU, select TEST. Go to the second page of  
the LOCAL TEST menu. Select DLB.  
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7.0 Diagnostics  
RECEIVER  
TRANSMITTER  
LOCAL  
MODEM  
TRANSMITTER  
RECEIVER  
DATA TERMINAL EQUIPMENT  
(DTE) AT LOCAL SITE  
REMOTE MODEM  
Figure 7-5. Digital Loopback Test (DLB).  
The DIGITAL LOOPBACK screen is displayed, with ON and OFF as the  
possible selections. Select ON to activate the test. The EIA status screen is  
displayed while the test is being conducted. Ensure that test data is being  
generated and watch for data errors. By transmitting test data and comparing  
it with the received copy, the DTE is checked for proper operation. To end  
the test, press the ENT pushbutton to return to the DIGITAL LOOPBACK  
screen. Then select OFF.  
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Modem 34336  
7.8 Remote Modem Diagnostics  
The Modem performs two tests on compatible remote modems: remote  
digital loopback (RDL) and remote digital loopback self test (RDLST).  
If a problem is encountered and the local Modem passes all diagnostic tests,  
the local Modem can test the remote modem.  
Two (noncontiguous) REMOTE TEST screens are on the Modem’s LCD.  
The remote tests are initiated from the REMOTE TEST menu. (Select RMT  
from MAIN MENU screen 2. Select TEST. Then, select the test type.) A  
remote test cannot be initiated unless the Remote Test option is enabled  
on the remote modem. This option (also REMOTE TEST on the LCD) is  
accessed via SETUP screen 4.  
7.8.1 REMOTE DIGITAL LOOPBACK (RDL) TEST  
The RDL test (Figure 7-6) allows testing of the local modem, remote modem  
and telephone line from the local site.  
In Hayes mode only, initiate the RDL test using the command &T6 (preceded  
by AT). In any mode, initiate the RDL test from the Modem’s front panel.  
Both modems should be on-line and should be tested at the DTE’s data rate.  
Ensure that the DTR circuit is on. If TR is present on the EIA status screen,  
the DTR circuit is on.  
RECEIVER  
TRANSMITTER  
LOCAL  
MODEM  
TRANSMITTER  
RECEIVER  
DATA TERMINAL EQUIPMENT  
(DTE) AT LOCAL SITE  
REMOTE MODEM  
Figure 7-6. Remote Digital Loopback Test (RDL).  
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7.0 Diagnostics  
From page 2 of the MAIN MENU, select RMT. Then select TEST.  
From the REMOTE TEST menu, select RDL.  
From the REMOTE DIGIT LOOP screen, select ON to activate the test. The  
status screen is displayed as the test is being conducted. Make sure that test  
data is being generated and watch for data errors. By transmitting test data  
and comparing it with the received copy, you can make sure the Modems  
and the telephone line are working.  
To end the test, press the ENT pushbutton to return to the REMOTE DIGIT  
LOOP screen. Then select OFF.  
7.8.2 REMOTE DIGITAL LOOPBACK SELF-TEST (RDLST)  
The RDLST allows testing of the local modem, remote modem, and  
telephone line from the local site (as did the previous test). However,  
test data is generated by internal modem circuitry as opposed to a DTE  
or external BERT. Figure 7-7 shows the connections automatically made  
during the test.  
In Hayes mode only, initate the RDLST using the command &T7 (AT &T7).  
In any mode, initate the RDLST test from the front panel.  
Both modems must be on-line. From the second page of the MAIN MENU,  
select RMT. Then, select TEST. From the REMOTE TEST menu, select  
RDLST.  
From the RDL SELFTEST screen, select ON to activate the test. The status  
screen is displayed as the test is being conducted. If "ER" is present on the  
status screen, the modem is detecting errors. If numerous errors are detected,  
take steps to try to identify their source.  
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Modem 34336  
TRANSMITTER  
RECEIVER  
PATTERN  
TRANSMITTER  
RECEIVER  
GENERATOR  
PATTERN  
DETECTOR  
REMOTE MODEM  
LOCAL MODEM  
Figure 7-7. Remote Digital Loopback Self Test.  
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APPENDIX A: DB25 Pin Assignments  
Appendix A: DB25 Pin Assignments  
Desig-  
LCD  
Pin nation Function  
Indicator Source  
1
2
AA  
BA  
BB  
CA  
CB  
CC  
AB  
CF  
+P  
-P  
Frame ground—not connected  
Transmit data (TD)  
TD  
RD  
RS  
CS  
MR  
DTE  
Modem  
DTE  
3
Receive data (RD)  
4
Request to send (RTS)  
Clear to send (CTS)  
5
Modem  
Modem  
Ground  
Modem  
Modem  
Modem  
Modem  
Modem  
DTE  
6
Data set (modem) ready (DSR)  
Signal Ground (SG)  
7
8
Carrier Detect (CD)  
CD  
9
Testing voltage, +10V  
Testing Voltage - 10V  
Transmit Clock (TC)  
10  
15  
17  
18  
20  
21  
22  
23  
24  
25  
DB  
DD  
CN  
CD  
CN  
CE  
CH  
DA  
CN  
Receive Clock (RC)  
Analog loopback (ALB) control1  
Data terminal ready (DTR)  
Remote digital loopback (RDL) control1  
Ring Indicator (RI)  
TR  
R
DTE  
DTE  
Modem  
DTE  
Speed Select (CH/CI)2  
External transmist clock  
Test mode indicator (TM)3  
DTE  
TM  
Modem  
1 +voltage activates indicated loopback test (only if ALB-DTE controled  
or RDL-DTE controled option is enabled); -voltage disables test.  
2 +voltage, 14,400 bps; -voltage, 2400 bps.  
3 Alternatively, pin 25 may be used for analog loopback (ALB) control.  
See Appendix D.  
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Modem 34336  
Appendix B: Quick Setup Configurations  
Table B-1 shows the complete default configuration for each of the Quick  
Setup modes. When you select a Quick Setup, the modem automatically sets  
all options as indicated in the table. The options are listed in the same order  
in which they appear on the LCD flow chart. See 2.0, Quick Start, for  
instructions on selecting Quick Setups.  
NOTE: All notes appear at the end of the table.  
Table B-1. Quick Setup Configurations.  
Default Settings Listed by Mode or Type of Operation  
V.25 bis  
2-WIRE 4-WIRE  
BELL  
OPTION  
HAYES ASYNC1 DUMB LEASED2 LEASED2 V.33  
2083  
2W-LL 4W-LL 4W-LL 2W-D  
Line Type Line Type  
2W-D  
19200  
300  
2W-D  
19200  
300  
2W-D  
19200  
300  
Speed  
(Data  
Rate)  
Speed, Max  
Speed, Min  
Speed Type  
V.42 Mode  
19200  
4800  
V.32  
19200  
4800  
V.32  
14400  
12000  
V.33  
4800  
4800  
208  
V.32  
Auto  
V.32  
V.32  
Auto  
V.42  
Error  
Auto1  
Auto  
Auto  
OFF  
OFF  
Correction MNP Class  
Options  
(Limit)  
5
5
5
5
5
5
5
V.42 Break  
Handling  
NDT/  
NEXP  
NDT/  
NEXP  
NDT/  
NEXP  
NDT/  
NEXP  
NDT/  
NEXP  
NDT/  
NDT/  
NEXP NEXP  
V.42  
Protocol  
LAPM/  
MNP  
LAPM/ LAPM/  
MNP MNP  
LAPM/ LAPM/ LAPM/ LAPM/  
MNP MNP MNP MNP  
V.42 bis  
Buffer  
Enable  
Enable  
38400  
Enable Enable  
Enable1 Enable  
Enable Enable Enable Enable  
Enable Enable Disable Disable  
DTE Speed  
38400  
38400  
38400  
38400  
38400 38400  
Flow Control  
DTE-DCE  
DC1/  
DC3  
DC1/  
DC3  
DC1/  
DC3  
DC1/  
DC3  
DC1/  
DC3  
DC1/  
DC3  
DC1/  
DC3  
Flow Control  
DCE-DTE  
DC1/  
DC3  
DC1/  
DC3  
DC1/  
DC3  
DC1/  
DC3  
DC1/  
DC3  
DC1/  
DC3  
DC1/  
DC3  
DTE Pass-thru  
Flow Control  
Disable  
Disable Disable Disable Disable Disable Disable  
See notes on page 127.  
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APPENDIX B: Quick Setup Configurations  
Table B-1 (continued). Quick Setup Configurations.  
Default Settings Listed by Mode or Type of Operation  
V.25 bis 2-WIRE 4-WIRE BELL  
OPTION  
HAYES ASYNC1 DUMB LEASED2 LEASED2 V.33  
2083  
Misc.  
Address  
999,999 999,999 999,999 999,999 999,999 999,999 999,999  
Dialer  
Mode  
Hayes V.25 bis/ OFF  
Async1  
OFF  
OFF  
OFF  
OFF  
Auto Answer Enable  
Data Format Async  
Character  
Enable Enable  
Disable  
Sync  
Disable Disable Enable  
Data  
Format  
Options  
Async1  
Async  
Sync  
Sync  
Sync  
Length  
10  
10  
10  
10  
10  
10  
10  
Parity  
None  
Even1  
None  
None  
None  
None  
None  
Disconnect RX Space  
Options  
Disconnect  
Enable Enable1 Enable  
Enable Enable1 Enable  
Enable  
Enable  
Enable  
Enable  
OFF  
Enable Enable Enable  
Enable Enable Enable  
Enable Enable Enable  
Enable Enable Enable  
TX Space  
Disconnect  
Carrier  
Disconnect  
Enable  
Enable  
OFF  
Enable Enable  
Enable Enable  
Line Current  
Disconnect  
RTS  
Disconnect  
OFF  
OFF  
OFF  
OFF  
OFF  
Test  
Options  
DSR During  
ALB  
ON  
ON  
ON  
ON  
ON  
ON  
ON  
Remote Test Enable  
Enable Enable  
True Normal  
Normal Normal Normal  
True Normal Normal  
Enable  
Normal  
Normal  
True  
Enable Enable Enable  
Normal Normal Normal  
Normal Normal Normal  
EIA  
Options  
CTS to EIA  
CD to EIA  
DSR to EIA  
True  
True  
True  
Normal  
DTR from  
EIA  
Normal Normal Normal  
True  
True  
True  
Normal  
ALB—DET  
controlled  
Disable Disable Disable Disable  
Disable Disable Disable  
See notes on page 127.  
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Modem 34336  
Table B-1 (continued). Quick Setup Configurations.  
Default Settings Listed by Mode or Type of Operation  
V.25 bis  
2-WIRE 4-WIRE  
BELL  
OPTION  
HAYES ASYNC1 DUMB LEASED2 LEASED2 V.33  
2083  
EIA  
Options  
(continued)  
RDL—DTE  
controlled  
Disable Disable Disable Disable Disable Disable Disable  
Normal Normal True True True True True  
TM to EIA  
Modem  
Setup  
Options  
CD Level,  
Leased  
-26 dBm -26 dBm -26 dBm -26 dBm -26 dBm -26 dBm -26 dBm  
-51 dBm -51 dBm -51 dBm -51 dBm -51 dBm -51 dBm -51 dBm  
CD Level,  
Dial  
TX Level,  
Leased  
0 dBm  
0 dBm 0 dBm 0 dBm  
0 dBm 0 dBm 0 dBm  
TX Level,  
Dial  
Permis. Permis. Permis. Permis. Permis. Permis. Permis.  
Signal Quality  
Level  
10^3  
10^3  
T-III  
10^3  
T-III  
10^3  
T-III  
10^3  
T-III  
10^3  
T-III  
10^3  
T-III  
Compromise  
Equalizer  
T-III  
Trellis Code  
Enable  
Enable Enable Enable  
Enable Enable Enable  
Transmit  
Clocking  
Internal Internal Internal Internal Internal Internal Internal  
T1 Timer  
0.8 sec 0.8 sec 0.8 sec 0.8 sec  
0.8 sec 0.8 sec 0.8 sec  
Enable Enable Enable  
See  
Auto-retrain  
Enable  
Enable Enable Enable  
See  
Answer/  
Originate  
ORIG  
ORIG  
ORIG  
note 2  
note 2  
ORIG  
ORIG  
Answer Tone 2100Hz 2100Hz 2100Hz 2100Hz 2100Hz 2100Hz 2100Hz  
Front Panel  
Enable  
Enable Enable Enable  
Enable Enable Enable  
Speaker  
Control  
Till-CD  
Till-CD Till-CD Till-CD  
Till-CD Till-CD Till-CD  
Speaker  
Volume  
High  
OFF  
High  
OFF  
High  
OFF  
High  
OFF  
High  
OFF  
High  
OFF  
High  
OFF  
Guard Tones  
V.13  
Operation  
OFF  
OFF  
OFF  
OFF  
OFF  
OFF  
OFF  
See notes on page 127.  
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APPENDIX B: Quick Setup Configurations  
Table B-1 (continued). Quick Setup Configurations.  
Default Settings Listed by Mode or Type of Operation  
V.25 bis 2-WIRE 4-WIRE BELL  
OPTION  
Carrier  
CTS  
HAYES ASYNC1 DUMB LEASED2 LEASED2 V.33  
2083  
V.33 and  
Bell 208A/B  
options  
Switched Switched4 Switched Switched Switched Constant Switched  
RTS  
0
RTS4  
04  
RTS  
0
RTS  
0
RTS  
0
ON  
0
RTS  
150 ms  
None  
OFF  
RTS-CTS  
Delay  
Auto-  
Recovery  
Options  
Auto-Recovery  
Select  
None  
None  
OFF  
20 min  
3
None  
OFF  
20 min  
3
None  
OFF  
20 min  
3
None  
OFF  
None  
OFF  
Return from  
Auto-Recovery OFF  
Auto-Recovery  
Test Interval 20 min  
20 min 20 min 20 min  
LCD  
Panel  
LCD  
Intensity  
3
3
3
3
See notes on next page.  
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Modem 34336  
Table B-1 (continued). Quick Setup Configurations.  
Notes:  
1V.25 bis synchronous configurations (character- and bit-oriented) are the same  
as the V.25 bis asynchronous confiugration except as follows:  
• V.42 MODE is OFF  
• BUFFER is disabled  
• DATA FORMAT is synchronous  
• PARITY is ODD  
• RX SPACE DISCONNECT is disabled  
• TX SPACE DISCONNECT is disabled  
• DIALER MODE (V.25 bis) is: Sync_c for character-oriented mode,  
Sync_b for bit-oriented mode.  
2Leased line originate and answer Quick Setups [(ORG) and (ANS) on the LCD]  
are the same except that ANSWER/ORIGINATE is set to ORIGINATE for the  
originate Quick Setups and is set to ANSWER for the answer Quick Setups (2-  
wire or 4-wire).  
3The V.32/208 auto-mode Quick Setup configuration is the same as the Dumb  
mode Quick Setup configuration except as follows:  
• SPEED TYPE is AUTO  
• DATA FORMAT is synchronous  
• V.13 OPERATION is set to TX and RX  
• CARRIER is constant  
• Summary Setup V.32/208 option (data pump options group) is  
set to 1 (enable).  
4Effectve for synchronous modes only.  
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APPENDIX C: Summary Setup  
Appendix C: Summary Setup  
C.1 Introduction to Summary Setup  
Summary Setup is designed to allow experienced users to quickly change  
option settings for any mode. There are three Summary Setup screens:  
SETUPS, AT PROFILES, and S-REG. They are briefly described on the  
next page.  
Because the screens show numerical codes with very little explanation,  
Summary Setup is recommended for experienced users only. Changes  
made through Summary Setup modify the active modem configuration  
and are saved to memory when you exit Summary Setup.  
ACCESSING SUMMARY SETUP  
Summary Setup is accessed from screen 6 of the SETUP menu. The  
SUMMARY screen includes a four-digit checksum value to the right of the  
word SUMMARY. This number changes if any of the option settings are  
changed. You can determine if any of the modem’s settings were changed,  
but you cannot determine what options were changed.  
From the SUMMARY screen, choose SETUPS to change options, AT to  
change options that are associated AT commands, or S-REG to change S  
Register values. (See Figure C-1.)  
KEY TO THE SUMMARY SETUP SCREENS  
Each Summary Setup Screen is essentially the same: brief descriptive  
information on the top line and a long string of numbers on the bottom line.  
The numbers are broken down into groups that represent a category  
of options (for example, EIA interface options).  
Each digit position represents an option, and the number in each digit  
position indicates the current option setting (parameter). The diagrams  
in this appendix show the following information:  
• Which options are included in each option group  
• Which option is indicated by each digit position within the group  
• The possible parameters for each option.  
NOTE  
The number in each digit position is the current iption setting  
(parameter). The diagrams of this Appendix show the factory-default  
setting for each option.  
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Modem 34336  
MAIN MENU  
<1>  
MAIN MENU  
<2>  
TALK QUICK DIAL  
SETUP TEST RMT  
1
2
3
1
2
2
3
SETUP  
<1>  
SETUP  
<6>  
TYPE LINE SPEED  
SUMMARY  
1
2
3
1
3
The four-digit hexa-  
decimal value in the  
upper right corner of  
the SUMMARY menu  
screen is a checksum  
derived from the  
Modem’s current con-  
figuration. The check-  
sum will change when  
any of the Modem’s  
options are changed.  
SUMMARY  
609E  
SETUPS AT S-REG  
1
2
3
PRI  
addr  
S-REG 00:01  
0011214E0 999 99  
DEC  
INC  
1
2
3
1
2
3
The SETUPS screen  
allows you to change  
all Modem options,  
including those that  
can be accessed  
through the front-panel  
LCD and those that  
can only be accessed  
or changed through  
Summary Setup.  
The S-REG screen  
allows you to change  
the S register values.  
AT PROFILES  
0
1
&Y0  
Do not change an S  
register value if you  
do not know its  
function. Doing so  
can adversely affect  
the configuration.  
1
2
3
The AT PROFILES screen  
allows you to access and  
change the Hayes mode user  
profiles (profile 0 and profile 1).  
Figure C-1. How to access the Summary-Setup Screens.  
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Appendix C: Summary Setup  
C.2 SETUPS Screen  
PRI  
addr  
Only part of the SETUPS screen can be  
displayed at any one time. The full screen  
is displayed below next to the numbers 1,  
2, and 3.  
0011214E0 999 99  
1
2
3
To make configuration and viewing easier, the screen is broken down into a  
number of sections. Use the front-panel pushbuttons to move around within  
the SETUPS screen (see Figure C-2).  
PRI  
addr  
dial  
eia  
v42<1>  
1
0011214E0 999 999 11111002210 000100000 20334300  
v42<2>  
L.L.  
pump1  
pump2  
pump3  
2
3
210001021 10000010 30100101100 00000110 00000000  
misc1  
misc2  
misc3  
1141110 0000 001FFFF1 71000000  
Primary Options:  
PRI  
0011214E0  
Speed limit, type: 0=V.32/V.32bis, 1=V.33, 2=Bell 208  
Speed limit, min. (bps): 4=19.2 K, 5=16.8 K, 6=14.4 K, 7=12.0 K, 8=9600,  
9=7200, A=4800, B=2400, C=1200, D=600, E=0-300, F=1200/75  
Speed limit, max. (bps): 4=19.2 K, 5=16.8 K, 6=14.4 K, 7=12.0 K, 8=9600,  
9=7200, A=4800, B=2400, C=1200, D=600, E=0-300, F=1200/75, G=EIA 23  
Buffer mode/speed conversion: 0=disable, 1=enable  
V.42 mode: 0=off, 1=mandatory, 2=automatic  
Dialer mode: 0=off, 1=Hayes, 2=DTR dialing, 3=V.25 bis–async  
4=V.25bis–sync/character-oriented, 5 =V.25 bis–sync/bit-oriented  
Character length (bits): 0=9, 1=10, 2=11  
Data format: 0 =Async,1=Sync  
Line type: 0=2-wire dial, 1=2-wire leased, 2=4-wire leased  
NOTE  
Speed limit, min. and Speed limit, max.: 7200 bps parameters are  
available only if V.32 bis mode is enabled.  
137  
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Modem 34336  
Primary Options:  
addr  
999 999  
Move the  
cursor one  
position to  
the left  
Move the  
cursor one  
position to  
the right  
Exit to the  
AT Profiles  
Screen  
TRANSMITTER  
RECEIVER  
Group  
Unit  
address address  
Move the  
Increase  
Move the  
cursor to  
the next  
section of  
commands  
cursor to  
the previous  
section of  
the value of  
the blinking  
character  
by one  
commands  
Figure C-2. How to move the cursor  
in the SETUPS screen using the  
pushbuttons.  
Dial Line Options:  
dial  
11111002210  
Pulse dialing rate (pulses per sec): 0=10, 1=20  
Wait for carrier (sec): 0=30, 1=45, 2=60, 3=75  
T1 timer (sec): 0=0, 1=0.3, 2=0.8, 3=1.6, 4=3.0  
Carrier detect level, dial (dBm): 0=-26,1=-33, 2=-43  
TX level, dial: 0=permissive, 1=programmable  
Disconnect, RTS (sec): 0=off, 1=140, 2=120. . . 7=20  
Disconnect, line current: 0=disable, 1=enable  
Disconnect, carrier: 0=disable, 1=enable  
Disconnect, TX space: 0=disable, 1=enable  
Disconnect, RX space: 0=disable, 1=enable  
Auto-answer: 0=disable, 1=enable  
EIA INTERFACE OPTIONS:  
e i a  
010211000  
Test mode: 0=normal, 1=true  
Remote digital loopback test: 0=disable, 1=enable  
Analog loopback test: 0=disable, 1=enable  
CTS: 0=normal, 1=follow RTS, 2=true, 3=on  
Carrier detect: 0=normal, 1=true, 2=toggle  
DSR: 0=true, 1=normal, 2=crossover  
DTR: 0=normal, 1=true  
138  
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Appendix C: Summary Setup  
V.42 ERROR CORRECTION OPTION:  
NOTE  
“V42 <1>” and “V42 <2>” are displayed to help indicate the relative  
positions of individual options across the LCD.  
V42 <1> V42 <2>  
00335311 200001021  
Link flow control: 0=disable, 1=enable, 2=slaved  
DCE pass-through flow control: 0=disable, 1=enable  
Selective retransmission: 0=disable, 1=enable  
V42 bis: 0=disable, 1=enable  
V.42 protocol: 0=LAPM only, 1=MNP only, 2=LAPM/MNP  
DTE pass-through flow control: 0=disable, 1=enable  
Flyback buffer: 0=enable, 1=disable  
Break handling: 0=none, 1=destr./expedited,  
2=nondestr./expedited, 3=non-destr./non-expedited  
MNP class (limit): 0=class 1, 1=class 2, 2=class 3,  
3=class 4, 4=class 5  
Flow control, DCE to DTE: 0=none, 1=CTS, 2=DC1/DC2,  
3=DC1/DC3  
Flow control, DTE to DCE: 0=none, 1=RTS, 2=DC1/DC2,\  
3=DC1/DC3  
Parity: 0 =none, 1=odd, 2=even, 3=mark, 4=space  
DTE speed (bps): 0=115.2 K, 1=57.6 K, 2=38.4 K, 3=19.2 K,  
4=9600, 5=7200, 6=4800, 7=2400, 8=1800, 9=1200,  
A=600, B=300  
LEASED LINE OPTIONS:  
L. L.  
10020010  
Auto-recovery test interval (min): 0=10, 1=20, 2=40, 3=60  
Auto-recovery return (sec): 0=off, 1=10, 2=40, 3=60, 4=120  
Auto-recovery select: 0=none, 1=dial if bad 30 sec,  
2=dial if bad 1 min, 3=dial if bad 2 min, 4=dial if bad 3 min,  
5=dial if bad 4 min, 6=manual recovery  
Carrier detect level, leased (dBm): 0=-26,1=-33, 2=-43  
TX level, leased (dBm): 0=0,1=-1 . . . 9=-9, A=-10 . . . F=-15  
TX clocking: O=internal, 1=received clocking, 2=external  
Answer/originate: 0=answer, 1 =originate  
139  
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Modem 34336  
DATA PUMP OPTIONS:  
NOTE  
“pump1” and “pump2” are displayed to help indicate the relative  
positions of individual options across the LCD.  
These five options apply to the Modem  
pump1  
pump2  
(MD833A–R2) only.  
2002103010100011110  
208 phase detection: 0=normal, 1=compensated  
V.32 mode: 0=V.32 extended, 1=V.32 bis  
Rate renegotiation (RRP): 0=disable, 1=enable  
Turnaround delay: 0=on, 1=off  
Satellite delay: 0=disable, 1=enable  
RTS to CTS delay (ms): 0=none, 1=15, 2=50, 3=150  
CTS: 0=always ON, 1=follow RTS  
Carrier type: 0=switched, 1=constant  
Phase reversal in answer tone: 0=enable, 1=disable  
Auxiliary channel: 0=disable, 1=enable  
Speed fallback: 0=disable, 1=enable  
Trellis coding: 0=disable, 1=enable  
Answer tone: 0=2100 Hz, 1=2225 Hz  
Guard tone: 0=off, 1=550 Hz, 2=1800  
Auto-retrain: 0=disable, 1=enable  
Signal quality level (error/bits): 0=1 in 103,1=1 in 105  
Compromise equalizer type: 0=off,1=I, 2=II, 3=III, 4=IV  
140  
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Appendix C: Summary Setup  
MISCELLANEOUS OPTIONS:  
NOTE  
“misc1” and “misc2” are displayed to help indicate the relative positions  
of individual options across the LCD. The dashes (-) are shown in this  
example to help indicate the relative positions of these three particular  
options across the LCD.  
misc1  
misc2  
1230000 0100  
––  
Multimode handshake: 0=T1 timer, 1=V.32 bis Annex A  
Answer tone detection: 0=disable, 1=enable  
ALB make busy: 0=disable, 1=enable  
V.13 operation: 0=off, 1=TX only, 2=RX only,  
3=TX and RX  
DTE=DCE speed: 0=disable, 1=enable  
V.25 bis DTR dialing: 0=disable, 1=enable  
Operating mode fallback: 0=Bell 212A and  
Bell 103,1=V.22/V.21/V.23  
Remote test: 0=disable, 1=enable  
DSR during ALB: 0=disable, 1=enable  
FP: 0=disable, 1=enable  
LCD intensity: 0,1 . . . 7 (7=greatest intensity)  
Speaker volume: 0 =low, 1=medium, 2=high  
Speaker control: 0=off, 1=on till CD, 2=on,  
3=off during dialing  
141  
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Modem 34336  
C.3 AT PROFILES Screen  
From the AT PROFILES screen you can select a Hayes mode configuration  
profile (either 0 or 1). Only part of the profile can be displayed at one time.  
The selected profile is used as the active configuration and is also designated  
as the default user profile.  
• Press pushbutton 1 to select profile 0.  
• Press pushbutton 2 to select profile 1.  
• Press pushbutton 3 to toggle between profile 0 and profile 1 as the  
default. You can achieve the same effect by issuing the &Y command  
(&Y0 or &Y1).  
AT PROFILES  
0
1
&Y0  
Factory-default settings are shown below.  
1
2
3
ATbeflmqvxy AT&c  
010210141  
1
1
2
3
Move the  
cursor one  
position to  
the left  
Move the  
cursor one  
position to  
the right  
Exit to the  
AT Profiles  
Screen  
TRANSMITTER  
RECEIVER  
The screen intially  
displays the  
Move the  
cursor to  
the previous  
section of  
commands  
Increase  
Move the  
cursor to  
the next  
AT commands  
and one  
AT& command.  
the value of  
the blinking  
character  
by one  
section of  
commands  
ATbeflmqvxy AT&cdgjlpqrsx s00 s18 s25 s26 AT\abcdeh kmnpq t vx  
010210141  
1210000000 001 000 005 001  
3150101630323300100  
S Registers  
AT\ Commands  
(most are for V.42 options)  
AT& Commands  
AT Commands  
Figure C-3. Selecting a Profile.  
NOTE  
Refer to Table 5-1, Hayes Compatible Commands, for an explanation of  
the commands represented in this diagram.  
142  
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Appendix C: Summary Setup  
C.4 S-REG Screen  
The S-REG screen may be used to read or change the value stored in an S  
register. For more information, see 5.3, S Registers.  
NOTE  
Not all S registers are intended for user access. Do not change the value  
of an A register if you do not know the register’s function. Doing so can  
adversely affect the modem’s configuration.  
The S-REG Screen displays an S register number and the value currently  
stored in the displayed S register.  
HOW TO CHANGE S REGISTER VALUES  
Select the desired S register number, then modify its value, as follows: Use the  
arrow pushbuttons to move the LCD cursor from one digit to the next. Then  
select DEC or INC to decrease or increase the selected (blinking) value until  
the desired value is displayed.  
S registers can also be changed by using the Hayes mode S command,  
as explained in 5.0 Hayes Emulation Mode.  
Stored value,  
S register number  
(decimal)  
or the value to be stored  
(hexadecimal)  
S-REG 00:01  
DEC  
INC  
1
2
3
Decrease the value  
of the blinking  
Increase the value  
of the blinking  
character by one  
character by one  
Figure C-3. Changing the S Register Value.  
143  
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Modem 34336  
Appendix D: Jumpers  
WARNING  
Jumpers should be switched only by qualified service personel.  
For most applications, there is no need to reset the modem’s internal jumper  
switches. However, a jumper switch will have to be reset if you need to do any  
of the following:  
• Connect frame ground to signal ground.  
• Switch from A/A1 control to MI/MIC control.  
• Strap the modem for use in a DC rack enclosure.  
• Change the function of EIA interface pin 25.  
If you need to reset a jumper switch, refer to the next page to determine the  
jumper that should be switched, where it is located, and how it should be set.  
The jumpers are numbered on the circuit board; for example, JP4 is jumper  
4. To access the jumpers, unscrew the four screws on the bottom of the  
modem and carefully lift off the cover.  
WARNING  
Improper setting of AC and DC power jumpers could result in serious  
damage to the modem.  
144  
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Appendix D: Jumpers  
JP2  
JP4  
JP7  
JP1  
JP3  
JP6  
JP5  
JP8  
Figure D-1. Modem Circuit Board—Jumper Locations.  
145  
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Modem 34336  
Table D-1. Jumper Switch Functions.  
JUMPER(S)  
Pins 1 and 2 connected Pins 2 and 3 connected  
JP1  
Frame and signal  
ground connected  
Frame and signal  
ground not connected  
JP2  
-12/-24/-48 VDC operation  
JP3, JP4  
-12/-24/-48 VDC operation  
(Set to same  
position)  
JP5, JP6  
A/A1 control  
MI/MIC control  
(Set to same  
position)  
JP7  
Pin 25 used for analog  
loopback (input)  
Pin 25 used as test  
mode indicator (output)  
JP8  
For factory use only. Do not change JP8 setting!  
Factory settings are shown in bold face.  
For each jumper, pin 1 is identified by a “1” printed on modem circuit board.  
(The JP2 pin 1 label may be difficult to read; JP2 pin 1 is the pin closest to  
the edge connector.)  
146  
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NOM Statement  
NORMAS OFICIALES MEXICANAS (NOM)  
ELECTRICAL SAFETY STATEMENT  
INSTRUCCIONES DE SEGURIDAD  
1. Todas las instrucciones de seguridad y operación deberán ser leídas antes de  
que el aparato eléctrico sea operado.  
2. Las instrucciones de seguridad y operación deberán ser guardadas para  
referencia futura.  
3. Todas las advertencias en el aparato eléctrico y en sus instrucciones de  
operación deben ser respetadas.  
4. Todas las instrucciones de operación y uso deben ser seguidas.  
5. El aparato eléctrico no deberá ser usado cerca del agua—por ejemplo, cerca  
de la tina de baño, lavabo, sótano mojado o cerca de una alberca, etc..  
6. El aparato eléctrico debe ser usado únicamente con carritos o pedestales que  
sean recomendados por el fabricante.  
7. El aparato eléctrico debe ser montado a la pared o al techo sólo como sea  
recomendado por el fabricante.  
8. Servicio—El usuario no debe intentar dar servicio al equipo eléctrico más allá  
a lo descrito en las instrucciones de operación. Todo otro servicio deberá ser  
referido a personal de servicio calificado.  
9. El aparato eléctrico debe ser situado de tal manera que su posición no  
interfiera su uso. La colocación del aparato eléctrico sobre una cama, sofá,  
alfombra o superficie similar puede bloquea la ventilación, no se debe colocar  
en libreros o gabinetes que impidan el flujo de aire por los orificios de  
ventilación.  
147  
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Modem 34336  
10. El equipo eléctrico deber ser situado fuera del alcance de fuentes de calor  
como radiadores, registros de calor, estufas u otros aparatos (incluyendo  
amplificadores) que producen calor.  
11. El aparato eléctrico deberá ser connectado a una fuente de poder sólo del  
tipo descrito en el instructivo de operación, o como se indique en el aparato.  
12. Precaución debe ser tomada de tal manera que la tierra fisica y la polarización  
del equipo no sea eliminada.  
13. Los cables de la fuente de poder deben ser guiados de tal manera que no  
sean pisados ni pellizcados por objetos colocados sobre o contra ellos,  
poniendo particular atención a los contactos y receptáculos donde salen del  
aparato.  
14. El equipo eléctrico debe ser limpiado únicamente de acuerdo a las  
recomendaciones del fabricante.  
15. En caso de existir, una antena externa deberá ser localizada lejos de las lineas  
de energia.  
16. El cable de corriente deberá ser desconectado del cuando el equipo no sea  
usado por un largo periodo de tiempo.  
17. Cuidado debe ser tomado de tal manera que objectos liquidos no sean  
derramados sobre la cubierta u orificios de ventilación.  
18. Servicio por personal calificado deberá ser provisto cuando:  
A: El cable de poder o el contacto ha sido dañado; u  
B: Objectos han caído o líquido ha sido derramado dentro del aparato; o  
C: El aparato ha sido expuesto a la lluvia; o  
D: El aparato parece no operar normalmente o muestra un cambio en su  
desempeño; o  
E: El aparato ha sido tirado o su cubierta ha sido dañada.  
148  
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© Copyright 1999. Black Box Corporation. All rights reserved.  
1000 Park Drive  
Lawrence, PA 15055-1018  
724-746-5500  
Fax 724-746-0746  
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