MARCH 1998
IC623A-M
IC624A-F
IC620A-F
IC620A-M
IC623A-F
IC624A-M
RS-232/485 Converter
1 0 / 1 0 0
S u p e r S w i t c h 8
C o d e : I C 6 2 0 A
CUSTOMER SUPPORT INFORMATION
Order toll-free in the U.S. 24 hours, 7 A.M. Monday to midnight Friday: 877-877-BBOX
FREE technical support, 24 hours a day, 7 days a week: Call 724-746-5500 or fax 724-746-0746
Mail order: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018
Web site: www.blackbox.com
•
E-mail: [email protected]
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RS-232/485 CONVERTER
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.
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NOM STATEMENT
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.
3
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RS-232/485 CONVERTER
TRADEMARKS
Product names mentioned in this manual may be
trademarks or registered trademarks of their respective
companies and are hereby acknowledged.
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TABLE OF CONTENTS
CONTENTS
1. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . .6
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . .8
2.1 Description . . . . . . . . . . . . . . . . . . . . . . .8
2.2 Features . . . . . . . . . . . . . . . . . . . . . . . . .9
3. Configuration . . . . . . . . . . . . . . . . . . . . . . . .11
3.1 Accessing the DIP Switches . . . . . . . . .11
3.1.1 DIP Switch S1 Settings . . . . . . . .16
3.1.2 DIP Switch S2 Settings . . . . . . . .18
3.2 Typical Applications . . . . . . . . . . . . . .20
4. Installation 24
4.1 Twisted-Pair Connection . . . . . . . . . . .22
4.1.1 Twisted-Pair Connections
Using Terminal Blocks . . . . . . .23
4.1.2 Twisted-Pair Connection
Using RJ-11 or RJ-45 . . . . . . . . .29
4.2 Wiring for Multipoint Circuits . . . . . .31
4.3 Connection to the EIA/TIA-574
Interface . . . . . . . . . . . . . . . . . . . . . . . .33
4.4 Operating the Converter . . . . . . . . . . .34
Appendix: EIA/TIA-574 Interface . . . . . . . . .35
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RS-232/485 CONVERTER
1. Specifications
Transmission Format — Asynchronous
Data Rate — Up to 115,200 bps
Range — Up to 9 miles (14.4 km)
Serial Interface — EIA/TIA-574 standard RS-232 DCE
Connectors — IC620A-F: (1) DB9 female,
(1) 5-position terminal block,
IC620A-M: (1) DB9 male, (1) 5-position terminal block;
IC623A-F: (1) DB9 female, (1) RJ-11 female,
IC623A-M: (1) DB9 male, (1) RJ-11 female;
IC624A-F: (1) DB9 female, (1) RJ-45 female,
IC624A-M: (1) DB9 male, (1) RJ-45 female
Transmit Line — 2-wire or 4-wire unconditioned,
unshielded, solid core, twisted pair
Transmit Mode — 4-wire, full- or half-duplex;
2-wire half-duplex
Control Signals — DSR turns ON immediately
after the terminal raises DTR; DCD turns ON
after recognizing the receive signal from the line;
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CHAPTER 1: Specifications
CTS turns ON after the terminal raises RTS
RTS/CTS Delay — 8 msec or “no delay”
Carrier — The carrier is switch-selected either
continuous operation or switched operation,
controlled by RTS
Surge Protection — 600 W power dissipation at 1 ms
Temperature — 32 to 122°F (0 to 50°C)
Humidity — 5 to 95%, noncondensing
Maximum Altitude — 10,000 ft. (304.8 m)
MTBF — 209,384 hours
Power — Draws operating power from EIA/TIA-574
data and control signals; no AC power or batteries
required. If necessary, 6 to 12 VDC can be applied
to pin 9 of the EIA/TIA-574 interface
Size — 2.5"H x 1.2"W x 0.75"D (6.4 x 3.1 x 1.9 cm)
Shipping Weight — 1 lb. (0.5 kg)
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RS-232/485 CONVERTER
2. Introduction
2.1 Description
The RS-232/485 Converter (IC620A) is an ultra-
miniature interface converter. Requiring no
AC power or batteries for operation, the Converter
supports asynchronous communication up to
115.2 Kbps over one or two unconditioned
twisted pairs. Distances up to 15 miles (24 km)
are attainable at lower data rates (1.2 Kbps,
19 AWG twisted pair).
The Converter can handle up to 31 terminal drops
in a multipoint polling environment. For RS-485
applications that require hardware handshaking, the
Converter passes one control signal in each direction
(see the last bullet point in Section 2.2 for an
explanation). The Converter may be configured for
high or low impedance, and the carrier may be set to
“constantly on” or “controlled by RTS.” The unit can
operate with or without “echo.” RTS/CTS delay may
be set for “no delay” or “8 ms delay.”
There are three options for twisted-pair
connection: terminal blocks with strain relief, RJ-11,
or RJ-45. Silicon Avalanche Diodes provide 600 watts
per wire of protection against harmful data-line
transient surges.
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CHAPTER 2: Introduction
Six models are available:
• DB9F/Term (IC620A-F)
• DB9M/Term (IC620A-M)
• DB9F/RJ-11 (IC623A-F)
• DB9M/RJ-11 (IC623A-M)
• DB9F/RJ-45 (IC624A-F)
• DB9F/RJ-45 (IC624A-M)
2.2 Features
•Operates asynchronously, point-to-point
or multipoint, over 2 or 4 wires.
•Up to 31 multipoint device drops in a polling
environment.
•Data rates up to 115.2 Kbps.
•Passes transmit and receive data, one control
signal in each direction.
•No AC power or batteries required.
•Variable high/low impedance settings.
•Able to operate with or without “echo.”
•Carrier can be set as “constantly on” or
“controlled by RTS.”
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RS-232/485 CONVERTER
•Twisted-pair connection via strain relief,
RJ-11, or RJ-45.
•Silicon Avalanche Diode surge protection.
•A Transmitter On signal received at the RS-485
RCV connection will cause DCD output at the
RS-232 connector to assert High.
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CHAPTER 3: Configuration
3. Configuration
The Converter is configured using two internal
4-position DIP switches. This section shows how to
access the DIP switches, provides an overview of the
factory-default settings, and describes all possible
configuration options. For instructions on how to
configure the Converter for specific applications,
see Section 3.2.
3.1 Accessing the DIP Switches
The Converter has a main PC board and a daughter-
board. DIP switch S1 is located on the underside of
the main PC board (see Figure 3-1). DIP switch S2
is located on the top of the daughterboard (see
Figure 3-2).
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RS-232/485 CONVERTER
Switch S1
Figure 3-1. Underside of the Converter’s main PC board,
showing the location of DIP switch S1.
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CHAPTER 3: Configuration
Switch S2
RCV
XMT
+
+
-
G
-
Figure 3-2. Top of the Converter’s daughterboard,
showing the location of DIP switch S2.
13
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RS-232/485 CONVERTER
To access the Converter’s internal PC boards,
insert a small flat-blade screwdriver between the
connector and the lip of the case and twist gently
as shown in Figure 3-3.
Figure 3-3. Opening the Converter’s plastic case with a small
screwdriver.
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CHAPTER 3: Configuration
Both DIP switch S1 and S2 are marked with
individual switch numbers 1 through 4. Use these
numbers, and the “ON” designation to orient the
switch properly (see Figure 3-4). Use a small
screwdriver or similar instrument to set each
individual switch.
ON
ON
1
2
3
4
OFF
Figure 3-4. Close-up of DIP switches S1 and S2,
showing ON/OFF orientation.
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RS-232/485 CONVERTER
3.1.1 DIP SWITCH S1 SETTINGS
DIP switch S1 is used to configure receive impedance
(termination), 2-wire/4-wire operation and “echo”
enable/disable. Table 3-1 shows the factory-default
settings for switch S1. Following Table 3-1 is a
detailed description of each switch.
Table 3-1. Switch S1 Summary Table (factory defaults in bold)
Position
Function
OFF Position
ON Position
S1-1
S1-2*
S1-3*
S1-4
RCV impedance (termination)
2-wire/4-wire
16 K ohms, typ.
4-wire
120 ohms
2-wire
2-wire/4-wire
4-wire
2-wire
Echo Mode
Echo OFF
Echo ON
*Switches S1-2 and S1-3 should be switched simultaneously.
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CHAPTER 3: Configuration
S1-1: Receive Impedance (Termination)
The setting for switch S1-1 selects the impedance
of the input receiver. You may select either a “low”
impedance of 120 ohms or a “high” impedance of
16 K ohms. By selecting the proper impedance for
each drop, you can have up to 50 receivers in one
application.
S1-1
Setting
On
Off
Low (120 ohms)
High (16 K ohms typical)
S1-2 and S1-3: 2-wire/4-wire Modes
Switches S1-2 and S1-3 are set together to determine
whether the Converter is in 2-wire or 4-wire
operating mode.
NOTE
2-wire mode is half-duplex only.
S1-2
S1-3
Setting
On
Off
On
Off
2-wire mode
4-wire mode
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RS-232/485 CONVERTER
S1-4: Echo Mode
The setting for switch S1-4 determines whether
the Converter echoes data back to the transmitting
device (half-duplex mode only).
S1-4
Setting
On
Off
Echo On
Echo Off
3.1.2 DIP SWITCH S2 SETTINGS
DIP switch S2 is used to configure carrier control,
RTS/CTS delay, and communication protocol. Table
3-2 shows the factory-default settings for switch S2.
Following Table 3-2 is a detailed description of each
individual switch.
Table 3-2. Switch S2 Summary Table (factory defaults in bold)
Position
Function
OFF Position
ON Position
S2-1
S2-2
S2-3*
S2-4*
Carrier Control
Constantly ON
No Delay
High
ON Position
8 msec
RTS/CTS Delay
“XMT Off” impedance
“XMT Off” impedance
Intermediate
Intermediate
High
*Switches S2-3 and S2-4 should be switched simultaneously.
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CHAPTER 3: Configuration
S2-1: Carrier Control Method
The setting for S2-1 determines whether the carrier
is “Constantly On” or “Controlled by RTS.” This
allows for operation in switched carrier, multipoint,
and/or hardware handshaking applications.
S2-1
Setting
On
Off
Controlled by RTS
Constantly On
NOTE
When in Controlled mode, RTS must go negative to turn
off the Transmitter and enable the Receiver.
S2-2: RTS/CTS Delay
The setting for switch S2-2 determines the amount of
delay between the time the Converter “sees” RTS and
when it sends CTS.
NOTE
The RTS/CTS Delay setting should be based upon
transmission timing.
S2-2
Setting
On
Off
8 msec
No delay
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RS-232/485 CONVERTER
S2-3 and S2-4: “Transmit Off” Impedance
Switches S2-3 and S2-4 are set together to determine
whether the receiving device “sees” the impedance
of the Converter’s transmitter as being “high” or
“intermediate” when the transmitter is turned off.
The “intermediate” setting is useful in half-duplex
environments where the receiving device does not
respond well to the “high” setting.
S2-3
S2-4
Setting
On
Off
On
Off
Intermediate impedance
High impedance
3.2 Typical Applications
The Converter is commonly used in five types
of applications:
• 4-wire/full-duplex/point-to-point
• 4-wire/half-duplex/point-to-point
• 2-wire/half-duplex/point-to-point
• 4-wire/multipoint
• 2-wire/multipoint
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CHAPTER 3: Configuration
The switch settings generally needed to
configure the Converter for these applications
are shown in Table 3-3.
NOTE
Do not change switch settings until you have carefully
read Section 3.1.
Table 3-3. Typical Converter Applications
Switch
Settings
Point-to-Point
Multipoint
4W
4W
4W HDX
2W
2W
S1-1: Rcv impedance
(Termination)
ON
ON
ON
Master—ON
Slaves—OFF
Last Slave—ON
S1-2: 2-wire/4-wire
S1-3: 2-wire/4-wire
OFF
OFF
OFF
OFF
ON
ON
OFF
OFF
ON
ON
S1-4: Echo
OFF
OFF
OFF
ON
OFF
ON
OFF
OFF
S2-1: Carrier Control
Master—OFF ON
Slaves—ON
S2-2: RTS/CTS Delay
ON
ON
ON
OFF
ON
S2-3: “Xmt Off” imp.
S2-4: “Xmt Off” imp.
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
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RS-232/485 CONVERTER
4. Installation
Once the Converter is properly configured, it is
ready to connect to your system. This section tells
you how to properly connect the Converter to the
twisted-pair and EIA/TIA-574 interfaces, and how
to operate the Converter.
4.1 Twisted-Pair Connection
The Converter supports 2-wire or 4-wire communi-
cation between two or more EIA/TIA-574 devices at
data rates up to 115.2 Kbps. There is one essential
requirement for installing the Converter:
To function properly, the Converter needs
one or two twisted pairs of metallic wire. These
pairs must be unconditioned dry metallic wire,
between 19 and 26 AWG solid copper core,
unshielded (the higher-number gauges may
limit distance). Standard dialup telephone
circuits that run through signal-equalization
equipment are not acceptable.
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CHAPTER 3: Configuration
For your convenience, the Converter is available
with several different twisted-pair interfaces: RJ-11
jack, RJ-45 jack, and terminal blocks with strain
relief. The Converter is also available with DB25
male or female connectors.
4.1.1 TWISTED-PAIR CONNECTIONS USING TERMINAL
BLOCKS
If your application requires you to connect one or
two pairs of bare wires to the Converter, you will
need to open the case to access the terminal blocks.
The following instructions tell you how to open the
case, connect the bare wires to the terminal blocks,
and fasten the strain-relief collar in place so the wires
won’t pull loose.
1. You should already have the case open for the
configuration procedure. If not, see Section 3.1.
2. Strip the outer insulation from the twisted pair(s)
about one inch from the end.
Figure 4-1. Stripping the outer insulation.
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RS-232/485 CONVERTER
3. Strip the insulation on each of the twisted- pair
wires about 1⁄8 inch.
Figure 4-2. Stripping the insulation on the twisted-pair wires.
4. In a two-pair circuit, connect one pair of wires to
XMT+ and XMT- (transmit positive and negative)
on the terminal block, making careful note of
which color is positive and which color is negative.
5. Connect the other pair of wires to RCV+ and RCV-
(receive positive and negative) on the terminal
block, again making careful note of which color
is positive and which color is negative.
Ultimately, you will want to construct a two-pair
crossover cable that makes a connection with the
two Converters as shown in Figure 4-3.
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CHAPTER 3: Configuration
XMT+----------------------------------------RCV+
XMT- --------------------------------------- RCV-
G-------------To Shield (Optional)
RCV+-----------------------------------------XMT+
RCV - ----------------------------------------XMT-
G
Figure 4-3. Two-Pair Crossover Cable.
6. In a single-pair circuit, use only the transmit
(XMT) pair as shown in Figure 4-4.
XMT+------------------------------------------XMT+
XMT - -----------------------------------------XMT-
Figure 4-4. Transmit Pair.
NOTE
If there is a shield around the twisted-pair cable, it may
be connected to “G” on the terminal block. To avoid
ground loops, we recommend connecting the shield at
the computer end only. A ground wire is not necessary
for proper operation of the Converter.
7. When you finish connecting the wires to the
terminal block, the assembly should resemble
Figure 4-5.
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RS-232/485 CONVERTER
Figure 4-5. Wires connected to the terminal block.
8. Place the two halves of the strain-relief assembly
on either side of the telephone wire and press
together very lightly. Slide the assembly so that
it is about two inches from the terminal posts
and press together firmly. If your cable diameter
is too small or too large for our strain relief, call
for technical support.
Figure 4-6. Installing the strain relief assembly.
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CHAPTER 3: Configuration
9. Insert the strain-relief assembly with the wire going
through it into the slot in the bottom half of the
modem case and seat it into the recess in the case.
(If the telephone wire is too thin to be held by
the strain-relief assembly, you will need to order a
different-sized strain relief. Call for technical
support.)
Figure 4-7. Completing the installation
of the strain-relief assembly.
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RS-232/485 CONVERTER
10. Bend the top of the case as necessary to place it
over the strain-relief assembly. Do not snap the
case together yet.
Figure 4-8. Closing the case.
11. Insert one captive screw through a saddle washer
and then insert the captive screw, with the washer
on it, through the hole in the DB25 end of the
case. Snap that side of the case closed. Repeat
the process for the other side. This completes
the cable installation.
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CHAPTER 3: Configuration
4.1.2 TWISTED-PAIR CONNECTION USING RJ-11 OR RJ-45
The RJ-11 and RJ-45 connectors on the Converter’s
twisted-pair interface are pre-wired for a standard
telco wiring environment. The signal/pin
relationships are shown in Figure 4-9.
RJ-11
Signal
RJ-45
Signal
1
1--------------GND
2--------------RCV-
3--------------XMT+
4--------------XMT-
5--------------RCV+
6--------------GND
1---------------N/C
2---------------GND
3---------------RCV-
1
4---------------XMT+
5---------------XMT-
6---------------RCV+
7---------------GND
8---------------N/C
1
Connection to ground is optional.
Figure 4-9. Signal/Pin Relationships.
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RS-232/485 CONVERTER
Signal
Pin#
Pin#
Signal
1
1
GND
1--------------6 GND
RCV-
2--------------4 XMT-
3--------------5 RCV+
4--------------2 XMT+
5--------------3 XMT+
XMT+
XMT-
RCV+
1
1
GND
6--------------1 GND
1
Connection to ground is optional.
Figure 4-10. RJ-11 Cable (4-wire).
Signal
Pin#
Pin#
Signal
1
1
GND
2--------------7 GND
RCV-
3--------------5 XMT-
4--------------6 RCV+
5--------------3 RCV-
6--------------4 XMT+
XMT+
XMT-
RCV+
1
1
GND
7--------------2 GND
Figure 4-11. RJ-45 Cable (4-wire).
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CHAPTER 3: Configuration
Signal
Pin#
Pin#
Signal
XMT+
XMT-
3---------------3XMT+
4---------------4XMT-
Figure 4-12. RJ-11 Cable (2-wire).
Signal
Pin#
Pin#
Signal
XMT+
XMT-
4--------------4 XMT+
5--------------5 XMT-
Figure 4-13. RJ-45 Cable (2-wire).
4.2 Wiring for Multipoint Circuits
The Converter supports multipoint applications
using a daisychain topology. This topology requires
special wiring, as well as specific DIP-switch settings
for master and slave units. Refer to Table 3-3 for
multipoint DIP switch settings.
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RS-232/485 CONVERTER
DAISYCHAIN TOPOLOGY
Using a daisychain topology, you may connect several
Converters together in a master/slave arrangement.
Maximum distance between the units will vary based
upon the number of drops, data rate, wire gauge,
etc. Call Technical Support for specific distance
estimates.
Figure 4-14 shows how to wire the two-pair cables
properly for a Converter daisychain topology.
XMT A
XMT B
RCV A
RCV B
XMT B
RCV A
RCV B
XMT B
RCV B
RCV A
XMT A
RCV B
RCV A
XMT A
MASTER
SLAVE 1
SLAVE 2
SLAVE 3
SLAVE N
XMT A
XMT A
XMT B
XMT B
RCV B
RCV A
Figure 4-14. Daisychain wiring for the Converter host and slaves.
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CHAPTER 3: Configuration
4.3 Connection to the EIA/TIA-574 Interface
The Converter is designed to plug directly into the
DB9 serial port of an EIA/TIA-574 DTE device (PC,
laptop, host). If you must use a cable to connect the
Converter to the DTE device, make sure that it is a
straight-through cable of the shortest possible
length—we recommend 6 ft. (1.8 m) or less.
The DB9 connector on the Converter is wired
according to the EIA/TIA-574 Standard, as shown
in Figure 4-15.
DB9
Signal
1---------------------CD
2---------------------RD
3---------------------TD
4---------------------DTR
5---------------------SG/FG
6---------------------DSR
7---------------------RTS
8---------------------CTS
9---------------------(Optional 6-12 VDC)
Figure 4-15. EIA/TIA-574 Standard.
NOTE
The Converter is configured as a DCE, and is therefore
designed to connect to a DTE. If you need to connect the
Converter to another DCE device, call technical support
for details about the proper crossover cable.
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RS-232/485 CONVERTER
4.4 Operating the Converter
Once the Converter is properly installed, it should
operate transparently—as if it were a standard cable
connection. Operating power is derived from the
RS-232 data and control signals; there is no ON/OFF
switch. All data signals from the RS-232 and RS-485
interfaces are passed straight through. One hardware
flow-control signal is also passed in each direction
(see the last bullet point in Section 2.2 for an
explanation).
34
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APPENDIX
Appendix: EIA/TIA-574 Interface
DB9
Signal
Direction
1----------------------CD
2----------------------RD
3----------------------TD
4----------------------DTR
5----------------------SG/FG
6----------------------DSR
7----------------------RTS
8----------------------CTS
Output
Output
Input
Input
———
Output
Input
Output
9----------------------Optional 6-12 VDC
35
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