AUGUST 2002
SC120A-R2
SC121A
2 x 2 SCSI Matrix Switch
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
•
E-mail: [email protected]
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2 X 2 SCSI MATRIX SWITCH
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.
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.
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NOM STATEMENT
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 objetos 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: Objetos 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.
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2 X 2 SCSI MATRIX SWITCH
TRADEMARKS USED IN THIS MANUAL
BLACK BOX and the
Corporation.
logo are registered trademarks of Black Box
Microsoft, Windows, and Windows NT are registered trademarks or trademarks of
Microsoft Corporation in the United States and/or other countries.
UL is a registered trademark of Underwriters Laboratories Incorporated.
Any other trademarks mentioned in this manual are acknowledged to be the property of the
trademark owners.
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TABLE OF CONTENTS
Contents
Chapter
Page
1. Specifications ..........................................................................................................7
2. Introduction ..........................................................................................................10
2.1 About the SCSI Switch ..................................................................................10
2.2 Features ..........................................................................................................10
2.2.1 LCD Panel..............................................................................................11
2.2.2 Front-Panel Controls ............................................................................11
2.3 Technical Description....................................................................................11
2.3.1 Available SCSI Switch Interfaces..........................................................11
2.3.2 General Hardware Description............................................................12
2.3.3 Ultra2 SCSI Compatibility ....................................................................12
2.3.4 SCSI Switch Installation........................................................................12
3. Installation ............................................................................................................15
3.1 What’s Included ............................................................................................15
3.2 AC Line Voltage ............................................................................................15
3.3 Switch Placement ..........................................................................................15
3.4 Power Equipment Off....................................................................................15
3.5 SCSI Interface Cabling ..................................................................................16
3.6 RS-232 Serial Port Cabling ............................................................................16
3.7 Ethernet LAN Port Cabling ..........................................................................16
4. Operator Controls and Indicators ......................................................................17
4.1 AC Power Switch ............................................................................................17
4.2 LCD Display, Keypad, and Indicators ..........................................................17
4.2.1 LCD Display ..........................................................................................17
4.2.2 Keypad ..................................................................................................18
4.2.3 Indicators ..............................................................................................18
4.3 LCD Display Control Menus ........................................................................18
4.4 SCSI Switch Port Configuration....................................................................21
4.5 SCSI Switch Default Configuration ..............................................................21
5. Configuration and Operation..............................................................................22
5.1 SCSI Cable Interface Requirements ............................................................22
5.2 Internal Terminator Selection......................................................................22
5.3 Selecting Internal Terminator Power ..........................................................25
5.4 Selecting External Terminator Power..........................................................25
5.5 Serial-Port Pinout ..........................................................................................26
5.6 LAN/Serial-Port Commands ........................................................................27
5.7 ASCII Character Reference for SCSI Switch Box Selection........................33
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2 X 2 SCSI MATRIX SWITCH
Chapter
Page
5. Configuration and Operation (continued)
5.8 Graphical User Interface (GUI) ................................................................33
5.9 Connecting Multiple SCSI Switches ..........................................................34
5.10 Typical Application......................................................................................34
5.11 Network Control of SCSI Switch ................................................................35
5.11.1 LAN Port Configuration ..................................................................35
5.11.2 Cfgswitch Utility................................................................................36
5.11.3 Apconcmd Utility..............................................................................37
6. SCSI Technical Information ................................................................................38
6.1 SCSI Basics......................................................................................................38
6.1.1 SCSI-1 ....................................................................................................38
6.1.2 SCSI-2 ....................................................................................................38
6.1.3 SCSI-3 ....................................................................................................38
6.1.4 Signal Wiring ........................................................................................38
6.1.5 Common Problems ..............................................................................39
6.1.6 Passive Terminators ..............................................................................39
6.1.7 Active Terminators................................................................................39
6.2 SCSI Installation Tips ....................................................................................39
6.3 SCSI Interface Signal Descriptions ..............................................................40
7. Troubleshooting....................................................................................................50
7.1 Calling Black Box ..........................................................................................50
7.2 Shipping and Packaging................................................................................50
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CHAPTER 1: Specifications
1. Specifications
SCSI Interface
Maximum Port Switching Delay: 3 ns
Maximum Signal Skew: 2 ns
Internal Terminator Power: 1 amp
Rear-Panel Connectors: 68-pin high-density
SCSI-1, SCSI-2, and SCSI-3 (also Ultra160 SCSI [“Ultra3 SCSI”] for SC120A-R2),
SPI-2 compatible; asynchronous and synchronous compatible; conforms to
ANSI X3.131 and X3T9.2
Single-Ended (SE) SCSI (SC120A-R2 Only)
Maximum Data Rate (8-bit Narrow): 20 MBps
Maximum Data Rate (16-bit Wide): 40 MBps
Maximum Port Cable Length: 6 meters (20 ft.)
Internal Terminator Impedance: 100 ohms
Terminator Disconnect Capacitance: 3 pF
Active Internal Bus Termination
Differential (DE) SCSI (SC121A Only)
Maximum Data Rate (8-bit Narrow): 40 MBps
Maximum Data Rate (16-bit Wide): 80 MBps
Maximum Port Cable Length: 25 meters (82 ft.)
Internal Terminator Impedance: 110 ohms
Terminator Disconnect Capacitance: 5 pF
Passive Internal Bus Termination
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2 X 2 SCSI MATRIX SWITCH
Low-Voltage Differential (LVD) SCSI (SC120A-R2 Only)
Maximum Data Rate (8-bit Narrow): 40 MBps for Ultra2 SCSI (narrow transfers
aren’t officially supported in the Ultra160 SCSI standard)
Maximum Data Rate (16-bit Wide): 160 MBps
Maximum Port Cable Length: 25 meters (82 ft.)
Internal Terminator Impedance: 105 ohms
Terminator Disconnect Capacitance: 3 pF
Active Internal Bus Termination
Serial Interface
Baud Rate: 9600 or 19,200 bps
Data Format: No parity, 8 bits, 1 stop bit (fixed)
Maximum Cable Length: 15 meters (50 ft.)
Rear-Panel Connectors: DB9
LAN Port
Protocol: TCP/IP
Interface: Ethernet
Data Rate: 10 MBps
Rear-Panel Connector: RJ-45
Agency Approvals
®
UL , CUL, FCC Class A, CE
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CHAPTER 1: Specifications
Physical
Temperature: 32 F to 149°F (0 to 65°C)
Humidity: Up to 90% relative humidity, noncondensing
Power: 95 to 260 VAC 10% (25 watts)
Size: 4.5"H x 11.3" W x 9.7"D (11.4 x 28.7 x 24.6 cm)
Weight: 5.1 lb. (2.3 kg)
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2 X 2 SCSI MATRIX SWITCH
2. Introduction
2.1 About the SCSI Switch
The 2 x 2 SCSI Matrix Switch is a high-performance electronic crosspoint switch
for use with the SCSI (Small Computer System Interface) bus. This product
enables two independent SCSI buses to be selected and electrically connected in
any combination via internal electronic switching circuits. The 2 x 2 SCSI Matrix
Switch eliminates the need to swap and reconfigure SCSI cables and bus
terminators when alternate system configurations are required.
In conjunction with the 2 x 2 SCSI Switch dual RS-232 serial interface, a
Graphical User Interface (GUI) allows the system administrator to remotely
operate and control SCSI-port configuration and termination, report SCSI-bus
activity, gather performance statistics, and set internal temperature points for
alarm notification. Standard DOS or modem software can also be used to control
the switch using simple ASCII control commands.
Up to 32 SCSI Switches can be connected together and controlled by one serial
port.
2.2 Features
• Ultra2, Ultra, and Fast SCSI compatible. SC120A-R2 is also Ultra160 SCSI
(a.k.a. “Ultra3 SCSI”) compatible.
• 80-MBps or (SC120A-R2 only) 160-MBps throughput (LVD).
• Easy-to-use LCD panel.
• Daisychain up to 32 switches.
• Share up to 32 SCSI peripherals.
• SC121A supports differential SCSI. SC120A-R2 supports single-ended or LVD
SCSI.
• Transparent electronic switching.
• LAN port for TCP/IP-based network control, RS-232 ports for serial control.
• Does not require SCSI-bus ID.
• User-installable.
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CHAPTER 2: Introduction
2.2.1 LCD PANEL
The 2 x 2 SCSI Matrix Switch features an easy-to-use, menu-driven LCD panel with
soft-touch MENU, ENTER, and directional keys. The LCD is lighted, which allows
for easy viewing and operation.
2.2.2 FRONT-PANEL CONTROLS
• Set and configure SCSI ports.
• Set termination.
• Set switch number.
• View power-supply status.
• View internal temperature.
• Set internal-temperature alarm.
• Set serial-port configuration.
• Display SCSI-bus busy status.
• Display port configuration.
2.3 Technical Description
2.3.1 AVAILABLE SCSI SWITCH INTERFACES
The 2 x 2 SCSI Matrix Switch is available in the following configurations:
• Single-ended/LVD interface (SC120A-R2)
• Differential interface (SC121A)
NOTE
Make sure that the SCSI Switch you’re installing is used with the
appropriate interface. Single-ended/LVD and differential SCSI devices
cannot be installed on the same switch unless a SCSI differential
converter is used.
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2 X 2 SCSI MATRIX SWITCH
2.3.2 GENERAL HARDWARE DESCRIPTION
The 2 x 2 SCSI Matrix Switch’s rear panel identifies each of the independent SCSI
ports. SCSI ports A and B have two daisychained connectors per port and SCSI
ports 1 and 2 have single connectors for installation of SCSI devices. You can install
the SCSI Switch at any point on the SCSI bus.
Each port has internal termination that can be turned on or off from the LCD
panel. External “terminator power” (TERMPWR) for devices and terminators are
provided by internal resettable fuses.
The SCSI Switch does not require a device ID and is completely transparent to
all computers and peripherals on the SCSI bus. No additional software is needed
for installation and operation. A universal switching power supply automatically
adapts to input voltages between 95 VAC and 260 VAC.
2.3.3 ULTRA2 SCSI COMPATIBILITY
The SCSI Switch supports Ultra2 SCSI, 80-MBps (wide) SCSI host adapters,
computers, and peripherals in asynchronous and synchronous mode. (SC120A-R2
also supports Ultra160 SCSI, 160-MBps devices.) The SCSI Switch conforms to
ANSI X3.131 and X3T9.2 specifications for single-ended devices. Disconnect and
reselect functions are fully supported to ensure complete SCSI compatibility.
2.3.4 SCSI SWITCH INSTALLATION
Ports A and B are fully bidirectional to ports 1 and 2 (see Figures 2-1 through 2-3).
You determine where to connect computers, host adapters, and peripherals. In
general, if daisychained ports are required for connection to external peripherals,
use ports A or B.
The LCD panel is used to select port connections and enable or disable each
internal SCSI port terminator. Refer to Chapter 4 for complete instructions on
operating the LCD keypad.
You can selectively enable or disable any internal terminator to meet system
configurations and requirements.
NOTES
1. For proper operation of any SCSI bus, there must not be a “hanging”
line or cable. Termination should be enabled on active SCSI ports that
are not connected through to another port.
2. Connections can be made to either connector on the appropriate port.
3. In Figures 2-1 and 2-3, “Term” shows where terminators should be
installed.
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CHAPTER 2: Introduction
SCSI Switch Ports
Figure 2-1. SC121A block diagram.
Figure 2-2. SC120A-R2 block diagram.
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2 X 2 SCSI MATRIX SWITCH
SCSI Switch (SC120A-R2)
Figure 2-3. Typical switch installation.
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CHAPTER 3: Installation
3. Installation
3.1 What’s Included
• (1) 2 x 2 SCSI Matrix Switch
• (1) AC power cord
• (1) 10-ft. (3-m) DB9-male-to-DB9-female RS-232 cable
• (1) DB9-male-to-DB25-female RS-232 adapter
• (1) SCSI Matrix Switch control software CD-ROM
• This users’ manual
If anything is missing or damaged, call Black Box at 724-746-5500.
3.2 AC Line Voltage
You can connect the SCSI Switch to any AC input voltage between 95 and 260 volts.
Unless otherwise specified, the switch will be shipped with a 110-volt power cord
for use in the USA. For a power cord that will work in your country (outside the
USA), call Black Box Technical Support.
3.3 Switch Placement
Place the SCSI Switch in a convenient location near the host computer or
peripherals. Keep SCSI cable lengths short to provide the best performance and
reliability. Make sure that the dual fans and ventilation slots on the sides of the
switch receive adequate airflow. Do not place the switch on or near any devices that
generate excessive heat.
3.4 Power Equipment Off
Power off all equipment and peripherals connected to the SCSI interface before
installing cables or terminators.
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2 X 2 SCSI MATRIX SWITCH
3.5 SCSI Interface Cabling
Both versions of the 2 x 2 SCSI Matrix Switch have 68-pin high-density connectors.
Single-ended devices can have cable lengths up to 20 ft. (6 m). Differential or low-
voltage differential (LVD) devices can be connected with up to 82 ft. (25 m) of
cable.
Connect the host adapter or peripheral to the rear-panel connector using a
proper SCSI cable. Section 6.1 describes standard SCSI-interface requirements.
When you connect devices to ports A and B, use one of the port connectors, not
both.
NOTE
Do not intermix single-ended/LVD and differential devices on any SCSI
chain unless a SCSI differential converter is used to convert from one
bus type to the other.
Figure 3-1. The SCSI Switch’s rear panel.
3.6 RS-232 Serial Port Cabling
The SCSI Switches have a DB9 female RS-232 serial port on their rear panel,
pinned so that you can use a straight-through-pinned DB9 male-to-female serial
cable (such as the one provided with the SCSI Switch) to connect it to the DB9
male serial ports on a PC. Pins 1, 2, 3, 5, and 6 (CD, TD, RD, SGND, and DSR
respectively) are functional on the SCSI Switch’s RS-232 port; Pins 4 and 8 (DTR
and CTS) are tied together; and Pins 7 and 9 (RTS and RI) have no function.
3.7 Ethernet LAN Port Cabling
The SCSI Switches have an RJ-45 female 10BASE-T Ethernet port on their rear
panel. Use a standard straight-through-pinned twisted-pair cable (CAT5 or higher)
to connect this port to an Ethernet hub, switch, or router. To connect this port
directly to a 10BASE-T port on a computer, you’ll need to use a cross-pinned cable.
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CHAPTER 4: Operator Controls and Indicators
4. Operator Controls and
Indicators
4.1 AC Power Switch
The AC power switch is located on the SCSI Switch’s rear panel. Move it to the “|”
position to turn on the switch.
NOTE
Always turn on the SCSI Switch before powering SCSI devices and
computers. This will ensure that devices are found when the system
boots up.
4.2 LCD Display, Keypad, and Indicators
4.2.1 LCD DISPLAY
The LCD display shows the selection parameters available.
SET PORTS
>
SET TERMINATION
DISPLAY PORTS
DISPLAY ACTIVITY
DISPLAY POWER TEMP
FRONT PANEL LOCK
SET SERIAL PORTS
SET SWITCH NUMBER
>
>
SET TEMP LIMIT
DISPLAY VERSION
Figure 4-1. The LCD display’s main menu.
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2 X 2 SCSI MATRIX SWITCH
4.2.2 KEYPAD
Use the keypad to select menu and setup parameters for the SCSI Switch.
• MENU: Returns to the SCSI Switch setup and configuration menu.
• ENTER: Selects the highlighted setup parameter.
• UP, DOWN, RIGHT, LEFT Arrows: Scrolls the cursor to enable menu
selection.
4.2.3 INDICATORS
The indicators provide SCSI Switch status information.
• POWER: Indicates that the SCSI Switch is powered.
• BUSY: Indicates that there is SCSI activity on one or more SCSI ports.
• ALARM: A visual and audible alarm indicates a failure of an internal power
supply or that the SCSI Switch has exceeded the set temperature limit.
NOTE
To disable the audible alarm, press the front-panel MENU key. The
ALARM light will remain lit until the condition is corrected.
4.3 LCD Display Control Menus
SET PORTS
SET PORTS
1
*
2
*
A
B
|
|
|
|
|
|
SET TERMINATION
SET TERMINATION
A *
|
|
B
|
1
|
2
|
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CHAPTER 4: Operator Controls and Indicators
DISPLAY PORTS
DISPLAY PORTS
| A 1 | A 2 |
| B 1 | B 2 |
SET SERIAL PORTS
SET SERIAL PORTS
COM 1
COM 2
DAISYCHAIN Y *
9600 *
9600 *
19200
19200
N
SET SWITCH NUMBER
SET SWITCH NUMBER
01
USE UP/DOWN KEYS
DISPLAY POWER, TEMPERATURE
DISPLAY POWER, TEMP
PWR SUPPLY GOOD
+25.5°C
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2 X 2 SCSI MATRIX SWITCH
SET TEMP LIMIT
SET TEMP LIMIT
MAX +40°C
CURRENT TEMP +26.0°C
DISPLAY BUS ACTIVITY
DISPLAY ACTIVITY
A
B
1
2
FRONT PANEL LOCK
FRONT PANEL UNLOCKED
ENTER PASSWORD
TO LOCK 0 0 0 0
DISPLAY VERSION
BLACK BOX
SC121A
x
S/N 2 1 0 0 3 0 3
H V D V E R 2 1 1 2 1 2 4 L A N
In the DISPLAY VERSION panel:
• “HVD,” “LVD,” or “SE” at bottom left indicates the current SCSI-bus interface
mode.
• “x” at top right indicates that the serial ports are locked.
• “LAN” at bottom right indicates that the LAN port is active.
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CHAPTER 4: Operator Controls and Indicators
4.4 SCSI Switch Port Configuration
The SCSI Switch has an internal memory device that retains the current
configuration and setup information. Switch port, termination, serial port, and
control parameters are saved as they are entered on the front panel.
4.5 SCSI Switch Default Configuration
The SCSI Switch default configuration as shipped from the factory is defined
below.
PORTS: A1, B2
TERMINATION: SC121A: All Off; SC120A-R2: A, B On/1, 2, Off
SERIAL PORTS: 9600 bps
SWITCH NUMBER: 01
TEMPERATURE ALARM: 40° Celsius (104˚F)
FRONT PANEL: Unlocked, password 0000
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2 X 2 SCSI MATRIX SWITCH
5. Configuration and Operation
5.1 SCSI Cable Interface Requirements
The 2 x 2 SCSI Matrix Switch can be installed at any point on the SCSI bus. Always
use high-quality cables for optimum computer performance and reliability.
The SC121A differential switch contains 68-pin high-density connectors for up
to 80-MB-per-second wide Ultra SCSI and Ultra2 SCSI computers and peripherals.
The maximum cable distance should not exceed 82 ft. (25 m).
The SC120A-R2 single-ended/low-voltage differential switch contains 68-pin
high-density connectors for up to 160-MB-per-second wide Ultra SCSI, Ultra2 SCSI,
and Ultra160 SCSI computers and peripherals:
• Low-Voltage Differential (LVD):
When operating with LVD devices, the SC120A-R2 supports 160-MBps wide
Ultra160 SCSI computers and peripherals. The maximum cable distance for
LVD should not exceed 82 ft. (25 m) total length.
• Single-Ended (SE):
When operating with SE devices, the SC120A-R2 supports 40-MBps wide Ultra
SCSI computers and peripherals. The maximum cable distance for SE should
not exceed 20 ft. (6 m) total length.
Black Box offers standard and custom SCSI cables for connecting the SCSI
Switch to host devices and peripherals. Call Black Box Technical Support for
details.
5.2 Internal Terminator Selection
The SCSI Switch contains internal SCSI-bus terminators for each port.
Termination is required at both ends of a SCSI bus for proper operation. Each
port can have its internal terminator enabled or disabled from the front-panel
display and keypad.
Refer to Figure 5-4 to select internal termination.
NOTE
Data errors will result if more than two sets of terminators are installed
on any SCSI bus (see Figures 2-1 and 2-2).
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CHAPTER 5: Configuration and Operation
SC120A-R2 TERMINATION CONFIGURATION
Internal termination on Logic Component is always on by default and is not
settable at the point of the logic components (see Figure 5-1). To ensure proper
termination when configuring the switch termination, always have the termination
enabled at the specified alphanumeric port and the termination disabled at the
specified numeric port.
Example:
Host adapter is connected to port 1 (port 1 termination disabled) target device
connected to port A (port A termination enabled), with port A1 enabled through
the switch (see Figure 5-1).
Figure 5-1. Termination configuration.
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2 X 2 SCSI MATRIX SWITCH
Figure 5-2. SC120A-R2 termination example 1.
Figure 5-3. SC120A-R2 termination example 2.
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CHAPTER 5: Configuration and Operation
5.3 Selecting Internal Terminator Power
On-board SCSI Switch terminators can be powered by internal 5-volt power or
externally from SCSI-bus “terminator power” (TERMPWR).
1
Internal 5V
E13, E14, E19, E20
2
3
or
E15, E16, E21, E22
External
Terminator
Power
Figure 5-4. Internal terminator-power jumpers.
Table 5-1. Jumper settings for internal termination.
SC120A-R2
SC121A
E14-Port A
E20-Port 1
E15-Port A
E21-Port 1
E13-Port B
E19-Port 2
E16-Port B
E22-Port 2
NOTE
The standard factory default connects internal terminators to internal
5 volts.
5.4 Selecting External Terminator Power
The SCSI Switch can supply external terminator power via an internal resettable
fuse. This fuse supplies 1 amp at 5 volts to the terminator-power (TERMPWR)
signal. The SCSI Switch contains internal protection and will not be affected if
other SCSI devices provide terminator power.
E5, E6, E21, E22
or
E17–E20
Figure 5-5. External terminator-power jumpers.
NOTE
Factory default is “Enabled” on all ports.
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2 X 2 SCSI MATRIX SWITCH
Table 5-2. Jumper settings for external termination.
SC120A-R2 SC121A
E6-Port A
E22-Port 1
E19-Port A
E17-Port 1
E5-Port B
E21-Port 2
E20-Port B
E18-Port 2
NOTE
The standard factory default connects internal terminators to internal
5 volts.
5.5 Serial-Port Pinout
The SCSI Switch contains two RS-232 serial ports, using DB9 female connectors;
these allow external control of the switch. The connectors are compatible with
standard RS-232 modem cables. The serial ports can be configured to operate
separate communications ports or as daisychained ports.
Daisychained mode allows one computer or terminal to communicate with
multiple SCSI Switches.
Table 5-3. Rear-panel RS-232 connector pinout.
Signal
Description
DB9 Pin
DB25 Pin
DCD
RXD
TXD
DTR
GND
DSR
RTS
CTS
RI
Data Carrier Detect
Receive Data
1
2
3
4
5
6
7
8
9
8
3
Transmit Data
2
Data Terminal Ready
Signal Ground
20
7
Data Set Ready
Request to Send
Clear to Send
6
4
5
Ring Indicator
22
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CHAPTER 5: Configuration and Operation
5.6 LAN/Serial-Port Commands
You can use simple ASCII-character commands to control the SCSI Switch through
either its LAN port (by opening a socket connection to port 3001) or one of its
RS-232 serial ports. For serial control, set your computer’s serial port this way:
a. Baud rate: 9600 (the switch’s factory default) or 19,200 bps.
b. Data format: 8 data bits, 1 stop bit, no parity.
c. Transmission mode: Half-duplex.
So, for example, the DOS command to set a PC for serial communication with the
switch would be MODE COMx 9600,N,8,1. Whether you’re using a LAN or serial
connection, commands have the same syntax (format):
a. Start sequence: ASCII <cr> (carriage return) followed by two slashes (“//”)
b. Switch box number (you need this even if you have only one SCSI Switch):
Box 1 - 7C hex (ASCII “|”)
Box 2 - 7D hex (ASCII “}”)
Box 3 - 7E hex(ASCII “~”)
Box 4 - 7F hex (ASCII <del>)
c. Port selection:
Port A to port 1: “A1”, port A to port 2: “A2”;
Port B to port 1: “B1”, port B to port 2: “B2”
NOTE
1. More than one port connection can be selected at the same time. For
example, to select A1B2, transmit “A1B2.”
2. “0” clears (disconnects) all numbered ports. For example, “A0” clears
any numbered port connected to port A.
d. Connection or disconnection type:
ASCII “K” connects the specified ports and strictly adheres to SCSI rules.
NOTE
With “K,” if port A or B is not specified, no action will be taken on that
port. If a connection is selected (for example, “A1”), that connection will
be made, and the other numbered port will be disconnected from that
lettered port. For example, entering “A2K” when port A is connected to
port 1 will disconnect port A from port 1 and connect it to port 2.
ASCII “N” connects the specified ports without breaking existing connections.
ASCII “F” disconnects the specified ports.
e. End sequence: ASCII <cr>
So, for example, the complete command to connect the first SCSI Switch’s port A
to port 2 and its port B to port 1 would look like this: <cr>//|A2B1K<cr>
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2 X 2 SCSI MATRIX SWITCH
Table 5-4. SCSI Switch commands.
Command
Cmd.
Example
Example Result or
Response
Char. Command String
Select Port
K
S
k
<cr>//|A1K<cr>
<cr>//|S<cr>
<cr>//|A1k<cr>
<cr>//|s<cr>
<cr>//|L<cr>
<cr>//|U<cr>
<cr>//|?<cr>
A & 1 connected
“//|a2b0K”
Report Port Status
Select Terminator
Report Terminator Status
Lock Front Panel
Unlock Front Panel
A & 1 terminated
“//|ab1k”
s
L
U
?
Panel locked
Panel unlocked
“//|text…”
Report Model, S/N, and
Date of Manufacture
Report Alarm Status
Report Temperature
a
t
<cr>//|a<cr>
<cr>//|t<cr>
“//|a00”
“//|t+23.5”
(Celsius)
Report Performance
P
I
<cr>//|P<cr>
<cr>//|I<cr>
“//|PAABB1122”
Report SCSI-Bus
Inactivity
“2C71” (hex, =
1137.7 s or 19 m)
Yank on SCSI Reset
Line
Y
<cr>//|AB1Y<cr>
Ports A, B, and 1
reset
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CHAPTER 5: Configuration and Operation
Table 5-4 (continued). SCSI Switch commands.
Command
Cmd.
Example
Example Result or
Response
Chars. Command String
Enable/Disable Alarm
Set Baud Rate
OA
OB
OC
OD
OP
<cr>//|OA0<cr>
<cr>//|OB10<cr>
<cr>//|OC0<cr>
<cr>//|OD06<cr>
<cr>//|OP3156<cr>
Alarm enabled
COM2 = 9600 bps
Daisychain enabled
Switch # = 6
Set Serial Port Mode
Set Switch Number
Set Lock/Unlock
Password
Password = 3156
Set Temperature Limit
Report Revision
OT
R
<cr>//|OT45<cr>
<cr>//|R<cr>
Max. temp. = 45˚C
“2024610”
Lock Serial Ports
OL
<cr>//|OL3156<cr>
//|OL1 pass
//|OL0 fail
Unlock Serial Ports
OU
OS
<cr>//OU3156<cr>
<cr>//|OS<cr>
//|OU1 pass
//|OU0 fail
Report Serial Port
Lock Status
//|OS1 lock
//|OS0 open
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2 X 2 SCSI MATRIX SWITCH
EXPANDED LIST OF COMMANDS
a. Select SCSI Port Matrix:
example command: <cr>//|A1B2K<cr>
report: none
NOTE
K - Connects specified ports, but also breaks former connections
and maintains proper termination as per SCSI rules.
N - Connects specified ports without regard for former connections or
termination.
F - Disconnects the specified ports.
b. Report SCSI Port Matrix Assignment Status
example command: <cr>//|S<cr>
example report: //|A1B2K
c. Select SCSI Terminator Matrix
example command: <cr>//|<AB12k><cr>
report: none
d. Report SCSI Terminator Status
example command: <cr>//|s<cr>
example report: //|AB12k
e. Lock Front Panel
example command: <cr>//|L<cr>
report: none
f. Unlock Front Panel
example command: <cr>//|U<cr>
report: none
g. Report Model, Serial Number, and Date of Manufacture:
example command: <cr>//|?<cr>
example report: //|SC121A 21121150 10-15-02
SC121A = model number
21121150 = serial number
10-15-02 = date of manufacture (mm-dd-yy)
h. Report Alarm Status:
example command: <cr>//|a<cr>
report format: //|axy (x and y = ASCII 1 or 0)
x: 0 = OK, 1= Overtemperature
y: 0 = OK, 1= Power-supply failure
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CHAPTER 5: Configuration and Operation
i. Report Temperature:
example command: <cr>//|t<cr>
example report: //|t+19.5
+19.5 = +19.5˚C, +67˚F
j. Report SCSI-Bus Performance:
example command: <cr>//|P<cr>
report format: //|P<aabb1122><cr>
For ports A, B, 1, and 2 respectively, aa, bb, 11, and 22 = ASCII
representations of 8-bit hexadecimal values from 00 to FF, where
00 represents 0% busy (completely idle) and FF represents 100% busy
k. SCSI-Bus Inactivity to SCSI Report:
example command: <cr>//|I<cr>
report format: 1111 2222
For ports 1 and 2 respectively, 1111 and 2222 = ASCII representations
of 16-bit hexadecimal values that express the length of time in tenths of
seconds that the port has been inactive (not transmitting or receiving
data). For example, “0A73” = 0 x 4096 (163) + 10 x 256 (162) + 7 x 16 +
3 tenths of seconds = 267.5 seconds = 4 minutes 27.5 seconds.
l. Yank on SCSI Reset line:
example command: <cr>//|B2Y<cr>
report: none
m. Enable/Disable Audible Alarm:
example command: <cr>//|OAx<cr> [x = ASCII 1 or 0]
x: 0 = enable alarm, 1 = disable alarm
report: none
n. Set Serial-Port Baud Rate:
example command: <cr>//|OBxy<cr> [x and y = ASCII 1 or 0]
x: 0 = COM1, 1 = COM2
y: 0 = 9600 bps, 1 = 19,200 bps
report: none
o. Set Mode of Serial (Comm) Port for RS-232 Port 2:
example command: <cr>//|OCx<cr> [x = ASCII 1 or 0]
x: 0 = use Port 2 for daisychaining, 1 = use Port 2 as a second serial port
report: none
Note: This command has no effect if the LAN port is enabled, which
disables RS-232 Port 2.
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2 X 2 SCSI MATRIX SWITCH
p. Set Switch (Device) Number:
example command: <cr>//|ODxx<cr>
xx = ASCII representation of decimal value from 01 through 32
report: none
q. Set “Lock/Unlock Front Panel” Password:
example command: <cr>//|OPxxxx<cr>
xxxx: ASCII 4-digit decimal number from 0000 to 9999
report: none
r. Set Temperature Limit:
example command: <cr>//|OT<cr>
xx: ASCII 2-digit decimal number from 15 to 55 (degrees C)
report: none
s. Report Revision of SCSI Switch’s Firmware:
example command: <cr>//|R<cr>
example report: 2059722
t. Lock Serial Ports:
example command: <cr>//|OLxxxx<cr>
xxxx: password set with OP command (ASCII 4-digit decimal number
from 0000 to 9999)
example report: “//|OL1 pass” if password entered correctly, “//|OL0 fail”
otherwise
u. Unlock Serial Ports:
example command: <cr>//|OUxxxx<cr>
xxxx: password set with OP command (ASCII 4-digit decimal number
from 0000 to 9999)
example report: “//|OU1 pass” if password entered correctly,
“//|OU0 fail” otherwise
v. Report Serial-Port Lock Status:
example command: <cr>//|OS<cr>
example report: “//|OS1 lock” if the serial ports are locked,
“//|OS0 open” otherwise
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CHAPTER 5: Configuration and Operation
5.7 ASCII Character Reference for SCSI Switch Box Selection
Switch #
ASCII
1
|
2
}
3
~
4
5
`
6
a
7
b
8
c
<DEL>
Switch #
ASCII
9
d
10
e
11
f
12
g
13
h
14
i
15
j
16
k
Switch #
ASCII
17
l
18
m
19
n
20
o
21
p
22
q
23
r
24
s
Switch #
ASCII
25
t
26
u
27
v
28
w
29
x
30
y
31
z
32
{
5.8 Graphical User Interface (GUI)
Your SCSI Switch is supplied with control software that is compatible with most
®
®
recent Microsoft Windows operating systems to allow remote control of the
switch. Follow instructions on the included CD-ROM to install the software.
Figure 5-6. Screen shot of GUI control panel.
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2 X 2 SCSI MATRIX SWITCH
5.9 Connecting Multiple SCSI Switches
Up to 32 SCSI Switches can be controlled by a single RS-232 serial interface. To
operate in this configuration, set the serial ports to operate in daisychained mode.
In Figure 5-7, “1” is RS-232 port 1 on each switch and “2” is RS-232 port 2.
Computer
RS-232
2
2
1
1
2
1
1
SCSI Switch
Box 1
SCSI Switch
Box 2
SCSI Switch
Box 4
SCSI Switch
Box 3
Figure 5-7. Multiple SCSI Switch configuration.
5.10 Typical Application
Figure 5-8 shows a sample application for the SCSI Switch. Many other
configurations are possible.
Ethernet
10BASE-T
LAN
connection
for LAN-
based
switch
control
Server
Server
SCSI
Switch
Tape Drive
Tape Drive
RAID
Figure 5-8. Sample application.
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CHAPTER 5: Configuration and Operation
5.11 Network Control of SCSI Switch
The 2 x 2 SCSI Matrix Switch may be controlled over a TCP/IP network through
its LAN port.
5.11.1 LAN-PORT CONFIGURATION
You can remotely control the SCSI Switch through a standard 10-Mbps Ethernet
connection running TCP/IP. In the SCSI Switch’s factory-default setting, the LAN
port will be enabled and the RS-232 COM2 port (which shares the same circuitry
and is most often used for daisychaining SCSI Switches) will be disabled. If you
want to daisychain SCSI Switches, you will need to disable the LAN port and enable
the COM2 port. To do this, scroll through the control menus in the switch’s front-
panel LCD (see Section 4.3) until you reach the SET SERIAL PORTS menu. Move
the cursor to the DAISY CHAIN option and press ENTER on the switch’s keypad to
change the setting from N to Y.
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2 X 2 SCSI MATRIX SWITCH
5.11.2 APCONCFG UTILITY
The apconcfg.exe utility is used to configure the TCP/IP address. This utility is
provided on the included CD-ROM. You can reconfigure the IP address by using
the IP Configuration Utility. Run apconcfg.exe from the CD-ROM provided with
your 2 x 2 SCSI Matrix Switch. A “Configure Network Switch” window will appear.
Enter the new IP address and switch MAC address in the appropriate fields. The
MAC address can be found on a label located on the bottom of the switch. You can
search for the IP address by clicking the search button in the “Configure Network
Switch.” This will bring up a “Search for Network Switches” window. Enter a
beginning IP address, an ending IP address, and click Search.
Command strings to control the SCSI Switch may be manually entered through
certain versions of HyperTerminal to support connections to IP addresses through
the LAN.
NOTE
You will need to specify port #3001 when establishing the connection.
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CHAPTER 5: Configuration and Operation
5.11.3 APCONCMD UTILITY
The apconcmd.exe utility enables the user to set switch parameters through the
LAN port. This utility is located on the CD-ROM provided with your SCSI Switch.
To change switch settings and termination for an SCSI Switch, run (at a DOS
prompt) APCONCMD.EXE from the CD-ROM.
Usage:
apconcmd [/?] [/i<IP address>] [/c<COM port>] [/b<baud rate>]
[/n<Switch number>] [/h<holdoff>] [/x] [/t<termination>]
[/s<Switch settings>] [/w<command>] [/r<command>]
Where:
/? = this message.
/i <IP address> = The IP address of the network-enabled SCSI Switch.
/c <COM port> = The number of the COM port to address (1 to 8; default = 1).
/b <baud rate> = The baud rate of the COM port (2400, 9600, or 19200 [bps];
default = 9600).
/n <Switch number> = The number of the SCSI Switch to change (1 to 32;
default = 1).
/h <holdoff> = SCSI-bus holdoff, in seconds. The SCSI Switch will not change
the switch settings on a bus until there has been no activity for the specified
number of seconds. Valid range is 0 to 25 seconds.
/x = Ignore SCSI-bus activity. Switch settings will be changed immediately.
/t <termination> = Termination can be turned on (“N”) or off (“F”) for each
port (A, B, 1, or 2). For example, “A2NB1F” activates termination for ports A
and 2, and it deactivates termination on ports B and 1. Termination on any of
the switch’s ports that aren’t specified in the command will not be affected.
/s<Switch settings> = The settings to be changed. For example, “A1B2NB1A2F”
connects ports A and 1 and B and 2 and disconnects ports B from 1 and A
from 2. Switch settings on any of the switch’s ports that aren’t specified in the
command will not be affected.
/w<command> = <command> is sent to the switch with no parsing. Any
response from the switch is ignored.
/r<command> = <command> is sent to the switch with no parsing. Any response
from the switch is displayed on the console’s error output.
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2 X 2 SCSI MATRIX SWITCH
6. SCSI Technical Information
6.1 SCSI Basics
6.1.1 SCSI-1
The original specification supports data transfers up to 5 MBps on an 8-bit wide
parallel data bus. SCSI-1 standards had some incompatibility problems between
host adapters and peripheral devices. The need to improve compatibility, increase
transfer rates, and add other features for better performance required a review of
the specifications.
6.1.2 SCSI-2
Improved compatibility and higher transfer rates were provided in this
enhancement. The addition of “Wide SCSI” permits 16 or 32 bits to be transferred
in parallel, the latter requiring two cables. In combination with the “Fast SCSI”
option, synchronous data transfers up to 10 MBps for 8-bit, 20 MBps for 16-bit, and
40 MBps for 32-bit buses were achieved.
6.1.3 SCSI-3
The most significant additions include the ability to address up to 32 devices, a
16-bit single-cable data bus, and serial SCSI protocol. The SCSI-3 standard has
been split into several subdocuments, including the SCSI Parallel Interface (SPI),
which is based on a layered protocol, and the SCSI Interlocked Protocol (SIP), a
software link protocol.
6.1.4 SIGNAL WIRING
The signal wiring used in a SCSI bus has an impact on bus performance. The two
wiring techniques generally used for SCSI are single-ended and differential. With
single-ended wiring, a single wire carries the signal from initiator to target. Single-
ended circuitry is not noise resistant and is generally limited to about 6 meters
(20 ft.) at data transfer speeds of 10 MB per second.
Differential wiring uses two wires for each signal and offers exceptional noise
resistance because it does not rely on a common ground. This allows cables up to
25 meters (82 ft.) and reliable operation at 10 MB or more per second. Differential
wiring and circuitry is more complex than single-ended and generally tends to be
more expensive to implement.
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CHAPTER 6: SCSI Technical Information
6.1.5 COMMON PROBLEMS
The majority of problems encountered with SCSI-bus installations are due to
unbalanced or improper impedances on the SCSI-bus transmission cables caused
by varying manufacturers’ peripheral devices. SCSI terminators compensate for
these inherent impedance mismatches on a SCSI bus where peripheral devices
such as hard drives, CD-ROM drives, scanners, or printers are used.
6.1.6 PASSIVE TERMINATORS
The most basic is a passive-resistance style terminator. This is usually supplied with
peripherals and frequently does a poor job of balancing the impedance of the
SCSI bus. Passive terminators are resistor networks that allow signal voltages to vary
with the load and terminator power supplied, resulting in unstable signals from
end to end on the bus and causing data errors. Passive terminators are no longer
recommended by ANSI for designs.
6.1.7 ACTIVE TERMINATORS
Active terminators add a voltage regulator to the circuit to regulate signal voltages
with varying loads and terminator power, allowing a consistent signal to be
transmitted everywhere on the bus. This in turn compensates for the varying bus
lengths and signal loads. All lines are terminated through 110-ohm resistors, which
are applicable to all narrow and wide single-ended applications. Active termination
is the minimum ANSI-recommended termination.
6.2 SCSI Installation Tips
• Keep your SCSI chain short. Official SCSI specifications limit the length of a SCSI
chain to no more that 6 m (20 ft.) for single-ended or 25 m (82 ft.) for
differential. Practical experience says the shorter, the better. The maximum
length you should allow between devices is 3 ft. (0.9 m).
• Never assign the same SCSI ID number to two devices residing on the same bus. SCSI
uses these numbers as addresses to ensure that information goes to the correct
location. Giving two devices the same address can result in lost information.
• Know that some SCSI-ID numbers may be reassigned. Internal boot hard drives are
usually set to ID “0” while secondary hard drives are set to “1”. Motherboards
or host adapters are generally set to ID “7”.
• Always terminate the first and last devices on the chain. Drives purchased specifically
for internal use nearly always arrive with terminators installed. If in doubt, call
the vendor you purchased the device from.
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2 X 2 SCSI MATRIX SWITCH
• If the last device on the chain has two SCSI connectors, attach the cable to one and a
terminator to the other. Otherwise, you’ll have an open connector that may cause
noise on the SCSI chain.
• Always turn off the power to your computer and SCSI devices before swapping cables or
moving devices around. SCSI cables contain sensitive data transmission lines and
one or more live power wires.
• Turn on your SCSI devices before you turn on the computer. Some SCSI devices will
not mount if they are not running when you power up your computer.
Shutting down your computer first and then the attached SCSI devices allows
your system to completely “flush” itself.
6.3 SCSI Interface Signal Descriptions
A total of 18 signals are required for the SCSI interface. These signals are described
as follows:
• BSY (BUSY): An “OR-tied” signal indicating that the bus is being used.
• SEL (SELECT): An “OR-tied” signal used either by an initiator to select a
target or by a target to reselect an initiator.
• C/D (CONTROL/DATA): A signal driven by a target that indicates whether
Control or Data information is on the data bus. True indicates Control.
• I/O (INPUT/OUTPUT): A signal driven by a target that controls the
direction of data movement on the data bus with respect to an initiator. True
indicates input to the initiator. This signal is also used to distinguish between
Selection and Reselection phases.
• MSG (MESSAGE): A signal driven by a target during the Message phase.
• REQ (REQUEST): A signal driven by a target to indicate a request for a
REQ/ACK data-transfer handshake.
• ACK (ACKNOWLEDGE): A signal driven by an initiator to indicate an
acknowledgment for a REQ/ACK data-transfer handshake.
• ATN (ATTENTION): A signal driven by an initiator to indicate the Attention
condition.
• RST (RESET): An “OR-tied” signal that indicates the Reset condition.
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CHAPTER 6: SCSI Technical Information
• DB0 through DB15, P, P1 (DATA BUS): Sixteen data-bit signals and two parity-
bit signals that together form a data bus. DB15 is the most significant bit and
has the highest priority during the Arbitration phase. Bit number, significance,
and priority decrease downward to DB0. A data bit is defined as a one when
the signal value is true and as a zero when the signal value is false. Data parity
DBP and DBP1 shall be odd.
Table 6-1. SCSI connector assignments for
single-ended (SE) 16-bit SCSI (wide).
Signal Name
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Pin Number
Signal Name
-DB12
-DB13
-DB14
-DB15
-DBP1
-DB0
Pin Number
1
2
35
36
37
38
39
40
41
42
43
44
45
46
47
48
3
4
5
6
7
-DB1
8
-DB2
9
-DB3
10
11
12
13
14
-DB4
-DB5
-DB6
-DB7
-DBP
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2 X 2 SCSI MATRIX SWITCH
Table 6-1 (continued). SCSI connector assignments for
single-ended (SE) 16-bit SCSI (wide).
Signal Name
Ground
Pin Number
Signal Name
Ground
Ground
TERMPWR
TERMPWR
Reserved
Ground
-ATN
Pin Number
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
Ground
TERMPWR
TERMPWR
Reserved
Ground
Ground
Ground
Ground
-BSY
Ground
Ground
-ACK
Ground
-RST
Ground
-MSG
Ground
-SEL
Ground
-C/D
Ground
-REQ
Ground
-I/O
Ground
-DB8
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CHAPTER 6: SCSI Technical Information
Table 6-1 (continued). SCSI connector assignments for
single-ended (SE) 16-bit SCSI (wide).
Signal Name
Ground
Pin Number
Signal Name
-DB9
Pin Number
32
33
34
66
67
68
Ground
-DB10
Ground
-DB11
Table 6-2. SCSI connector assignments for
differential 16-bit SCSI (wide).
Signal Name
+DB(12)
+DB(13)
+DB(14)
+DB(15)
+DB(P1)
Ground
+DB(0)
Pin Number
Signal Name
-DB(12)
-DB(13)
-DB(14)
-DB(15)
-DB(P1)
Ground
-DB(0)
Pin Number
1
2
35
36
37
38
39
40
41
42
43
44
45
3
4
5
6
7
+DB(1)
8
-DB(1)
+DB(2)
9
-DB(2)
+DB(3)
10
11
-DB(3)
+DB(4)
-DB(4)
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2 X 2 SCSI MATRIX SWITCH
Table 6-2 (continued). SCSI connector assignments for
differential 16-bit SCSI (wide).
Signal Name
+DB(5)
+DB(6)
+DB(7)
+DB(P)
DIFFSENS
TERMPWR
TERMPWR
Reserved
+ATN
Pin Number
Signal Name
-DB(5)
-DB(6)
-DB(7)
-DB(P)
Ground
TERMPWR
TERMPWR
Reserved
-ATN
Pin Number
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
Ground
+BSY
Ground
-BSY
+ACK
-ACK
+RST
-RST
+MSG
-MSG
+SEL
-SEL
+C/D
-C/D
+REQ
-REQ
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CHAPTER 6: SCSI Technical Information
Table 6-2 (continued). SCSI connector assignments for
differential 16-bit SCSI (wide).
Signal Name
+I/O
Pin Number
Signal Name
-I/O
Pin Number
29
30
31
32
33
34
63
64
65
66
67
68
Ground
+DB(8)
+DB(9)
+DB(10)
+DB(11)
Ground
-DB(8)
-DB(9)
-DB(10)
-DB(11)
Table 6-3. SCSI connector assignments for
low-voltage differential (LVD) 16-bit SCSI (wide).
Signal Name
+DB(12)
+DB(13)
+DB(14)
+DB(15)
+DB(P1)
+DB(0)
Pin Number
Signal Name
-DB(12)
-DB(13)
-DB(14)
-DB(15)
-DB(P1)
-DB(0)
Pin Number
1
2
3
4
5
6
7
8
9
35
36
37
38
39
40
41
42
43
+DB(1)
-DB(1)
+DB(2)
-DB(2)
+DB(3)
-DB(3)
45
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2 X 2 SCSI MATRIX SWITCH
Table 6-3 (continued). SCSI connector assignments for
low-voltage differential (LVD) 16-bit SCSI (wide).
Signal Name
+DB(4)
Pin Number
Signal Name
-DB(4)
Pin Number
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
+DB(5)
-DB(5)
+DB(6)
-DB(6)
+DB(7)
-DB(7)
+DB(P)
Ground
DIFFSENS
TERMPWR
TERMPWR
Reserved
Ground
+ATN
-DB(P)
Ground
Ground
TERMPWR
TERMPWR
Reserved
Ground
-ATN
Ground
+BSY
Ground
-BSY
+ACK
-ACK
+RST
-RST
+MSG
-MSG
46
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CHAPTER 6: SCSI Technical Information
Table 6-3 (continued). SCSI connector assignments for
low-voltage differential (LVD) 16-bit SCSI (wide).
Signal Name
+SEL
Pin Number
Signal Name
-SEL
Pin Number
27
28
29
30
31
32
33
34
61
62
63
64
65
66
67
68
+C/D
-C/D
+REQ
-REQ
+I/O
-I/O
+DB(8)
+DB(9)
+DB(10)
+DB(11)
-DB(8)
-DB(9)
-DB(10)
-DB(11)
47
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2 X 2 SCSI MATRIX SWITCH
Table 6-4. SCSI distance/device support.
STA Term
Maximum Bus Length (M)
Maximum Devices
SE
HVD
25
25
25
25
—
LVD
—
—
—
—
—
—
—
—
25
12
25
12
SCSI-1
6
8
8
Fast SCSI
6
Fast Wide SCSI
Ultra SCSI
6
16
8
1.5
3
Ultra SCSI
4
Wide Ultra SCSI
Wide Ultra SCSI
Wide Ultra SCSI
Ultra2 SCSI
—
25
—
16
8
1.5
3
—
4
N/A
N/A
N/A
N/A
25
12
25
12
2
Ultra2 SCSI
8
Wide Ultra2 SCSI
Wide Ultra2 SCSI
2
16
48
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CHAPTER 6: SCSI Technical Information
To access jumper options:
Remove the four screws on the bottom of the unit. Then lift off the cover.
Figure 6-1. SCSI Switch component placement.
• Internal termination jumper block: E13, E14, E19, E20 on SC120A-R2 or
E15, E16, E21, E22 on SC121A (see Section 5.3).
49
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2 X 2 SCSI MATRIX SWITCH
7. Troubleshooting
7.1 Calling Black Box
If you determine that your 2 x 2 SCSI Matrix Switch is malfunctioning, do not
attempt to alter or repair the unit. It contains no user-serviceable parts. Contact Black
Box at 724-746-5500.
Before you do, make a record of the history of the problem. We will be able to
provide more efficient and accurate assistance if you have a complete description,
including:
• the nature and duration of the problem;
• when the problem occurs;
• the components involved in the problem;
• any particular application that, when used, appears to create the problem or
make it worse; and
• the results of any testing you’ve already done.
7.2 Shipping and Packaging
If you need to transport or ship your 2 x 2 SCSI Matrix Switch:
• Package it carefully. We recommend that you use the original container.
• If you are shipping the switch for repair, make sure you include everything that
came in the original package. Before you ship, contact Black Box to get a
Return Authorization (RA) number.
50
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LEGAL INFORMATION
DISCLAIMERS AND NOTICES
The manufacturer specifically disclaims the implied warranties for this product of
merchantability and fitness for a particular purpose. Some states and provinces do
not allow limitations on how long an implied warranty lasts, so the above limitation
or exclusion might not apply to you.
In no event shall the manufacturer or its authorized representatives be liable for
any lost profits or direct, indirect, special, incidental, or consequential damages,
whether based on contract, tort, or any other legal theory.
No part of this manual may be reproduced, copied, or translated without prior
written approval of the manufacturer or its authorized representatives.
The manufacturer and its authorized representatives reserve the right to revise
this publication from time to time without being obliged to notify any person or
organization of such revision. We have prepared this manual for use by customers
as a guide for the proper installation, operation, and maintenance of this
equipment. The illustrations, specifications, and other information contained in
this document are the property of the manufacturer and its authorized
representatives, and any unauthorized use or disclosure of this information is
prohibited.
The manufacturer and its authorized representatives make no warranty of any
kind with regard to this manual. We shall not be liable for errors contained herein
or for incidental consequential damages in connection with the furnishing,
performance, or use of this material.
51
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© Copyright 2002. Black Box Corporation. All rights reserved.
1000 Park Drive
•
Lawrence, PA 15055-1018
•
724-746-5500
•
Fax 724-746-0746
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