Black Box SC120A-R2, SC121A User Manual

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2 x 2 SCSI Matrix Switch

AUGUST 2002

SC120A-R2

SC121A

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: info@blackbox.com

FCC/IC RFI STATEMENTS, EU DECLARATION OF CONFORMITY

FEDERAL COMMUNICATIONS COMMISSION AND INDUSTRY CANADA

RADIO-FREQUENCY INTERFERENCE STATEMENTS

This equipment generates, uses, and can radiate radio-frequency energy, and if not installed and used properly, that is, in strict accordance with the manufacturer’s instructions, may cause interference to radio communication. It has been tested and found to comply with the limits for a Class A computing device in accordance with the specifications in Subpart B of Part 15 of FCC rules, which are designed to provide reasonable protection against such interference when the equipment is operated in a commercial environment. Operation of this equipment in a residential area is likely to cause interference, in which case the user at his own expense will be required to take whatever measures may be necessary to correct the interference.

Changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment.

This digital apparatus does not exceed the Class A limits for radio noise emission from digital apparatus set out in the Radio Interference Regulation of Industry Canada.

Le présent appareil numérique n’émet pas de bruits radioélectriques dépassant les limites applicables aux appareils numériques de la classe A prescrites dans le Règlement sur le brouillage radioélectrique publié par Industrie Canada.

EUROPEAN UNION DECLARATION OF CONFORMITY

This equipment complies with the requirements of the European EMC directive 89/336/EEC.

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.

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.

2 X 2 SCSI MATRIX SWITCH

TRADEMARKS USED IN THIS MANUAL

BLACK BOX and the logo are registered trademarks of Black Box

Corporation.

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.

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

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

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

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

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)

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.

CHAPTER 2: Introduction

2.2.1 LCD P

ANEL

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 F

RONT-PANELCONTROLS

• 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 A

VAILABLE

SCSI S

WITCHINTERFACES

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.

2 X 2 SCSI MATRIX SWITCH

2.3.2 G

ENERALHARDWAREDESCRIPTION

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 U

LTRA

2 SCSI C

OMPATIBILITY

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 S

WITCHINSTALLATION

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.

CHAPTER 2: Introduction

Figure 2-1. SC121A block diagram.

Figure 2-2. SC120A-R2 block diagram.

SCSI Switch Ports

2 X 2 SCSI MATRIX SWITCH

Figure 2-3. Typical switch installation.

SCSI Switch (SC120A-R2)

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.

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 lowvoltage 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.

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 D

ISPLAY

The LCD display shows the selection parameters available.

Figure 4-1. The LCD display’s main menu.

> SET TEMP LIMIT

DISPLAY VERSION

DISPLAY POWER TEMP FRONT PANEL LOCK

> SET SERIAL PORTS

SET SWITCH NUMBER

SET PORTS

> SET TERMINATION

DISPLAY PORTS DISPLAY ACTIVITY

2 X 2 SCSI MATRIX SWITCH

4.2.2 K

EYPAD

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 I

NDICATORS

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 TERMINATION

| A *| B| 1| 2|

SET PORTS

12 A| * | | B| | * |

CHAPTER 4: Operator Controls and Indicators

DISPLAY PORTS

SET SERIAL PORTS

SET SWITCH NUMBER

DISPLAY POWER, TEMPERATURE

DISPLAY POWER, TEMP

PWR SUPPLY GOOD +25.5°C

SET SWITCH NUMBER

USE UP/DOWN KEYS

SET SERIAL PORTS

COM 1 9600 * 19200 COM 2 9600 * 19200 DAISYCHAIN Y * N

DISPLAY PORTS | A 1 | A 2 | | B 1 | B 2 |

2 X 2 SCSI MATRIX SWITCH

SET TEMP LIMIT

DISPLAY BUS ACTIVITY

FRONT PANEL LOCK

DISPLAY VERSION

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.

BLACK BOX

SC121A

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

FRONT PANEL UNLOCKED

ENTER PASSWORD

TO LOCK 0 0 0 0

DISPLAY ACTIVITY

A B 1 2

SET TEMP LIMIT MAX +40°C

CURRENT TEMP +26.0°C

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

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).

CHAPTER 5: Configuration and Operation

SC120A-R2 T

ERMINATIONCONFIGURATION

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.

2 X 2 SCSI MATRIX SWITCH

Figure 5-2. SC120A-R2 termination example 1.

Figure 5-3. SC120A-R2 termination example 2.

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).

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.

Figure 5-5. External terminator-power jumpers.

NOTE

Factory default is “Enabled” on all ports.

Internal 5V

External

Terminator

Power

E13, E14, E19, E20

E15, E16, E21, E22

E5, E6, E21, E22

E17–E20

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 Data Carrier Detect 1 8 RXD Receive Data 2 3 TXD Transmit Data 3 2 DTR Data Terminal Ready 4 20 GND Signal Ground 5 7 DSR Data Set Ready 6 6 RTS Request to Send 7 4 CTS Clear to Send 8 5 RI Ring Indicator 9 22

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 3 - 7E hex(ASCII “~”) Box 2 - 7D 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>

2 X 2 SCSI MATRIX SWITCH

Table 5-4. SCSI Switch commands.

Command Cmd. Example Example Result or

Char. Command String Response

Select Port K <cr>//|A1K<cr> A & 1 connected

Report Port Status S <cr>//|S<cr> “//|a2b0K”

Select Terminator k <cr>//|A1k<cr> A & 1 terminated

Report Terminator Status s <cr>//|s<cr> “//|ab1k”

Lock Front Panel L <cr>//|L<cr> Panel locked

Unlock Front Panel U <cr>//|U<cr> Panel unlocked

Report Model, S/N, and ? <cr>//|?<cr> “//|text…” Date of Manufacture

Report Alarm Status a <cr>//|a<cr> “//|a00”

Report Temperature t <cr>//|t<cr> “//|t+23.5”

(Celsius)

Report Performance P <cr>//|P<cr> “//|PAABB1122”

Report SCSI-Bus I <cr>//|I<cr> “2C71” (hex, = Inactivity 1137.7 s or 19 m)

Yank on SCSI Reset Y <cr>//|AB1Y<cr> Ports A, B, and 1 Line reset

CHAPTER 5: Configuration and Operation

Table 5-4 (continued). SCSI Switch commands.

Command Cmd. Example Example Result or

Chars. Command String Response

Enable/Disable Alarm OA <cr>//|OA0<cr> Alarm enabled

Set Baud Rate OB <cr>//|OB10<cr> COM2 = 9600 bps

Set Serial Port Mode OC <cr>//|OC0<cr> Daisychain enabled

Set Switch Number OD <cr>//|OD06<cr> Switch # = 6

Set Lock/Unlock OP <cr>//|OP3156<cr> Password = 3156 Password

Set Temperature Limit OT <cr>//|OT45<cr> Max. temp. = 45˚C

Report Revision R <cr>//|R<cr> “2024610”

Lock Serial Ports OL <cr>//|OL3156<cr> //|OL1 pass

//|OL0 fail

Unlock Serial Ports OU <cr>//OU3156<cr> //|OU1 pass

//|OU0 fail

Report Serial Port OS <cr>//|OS<cr> //|OS1 lock Lock Status //|OS0 open

2 X 2 SCSI MATRIX SWITCH

XPANDEDLIST OFCOMMANDS

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

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.

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

CHAPTER 5: Configuration and Operation

5.7 ASCII Character Reference for SCSI Switch Box Selection

Switch # 12345678 ASCII | } ~ <DEL> ` a b c

Switch # 9 10 11 12 13 14 15 16 ASCII d e f g h i j k

Switch # 17 18 19 20 21 22 23 24 ASCII l m nopqr s

Switch # 25 26 27 28 29 30 31 32 ASCII t u v w xyz{

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.

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.

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.

Figure 5-8. Sample application.

Server

Ethernet

LAN

Tape Drive

RAID

Server

SCSI

Switch

10BASE-T

connection

for LAN-

based switch

control

Computer

SCSI Switch

Box 1

SCSI Switch

Box 2

SCSI Switch

Box 3

SCSI Switch

Box 4

RS-232

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-P

ORTCONFIGURATION

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 frontpanel 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.

2 X 2 SCSI MATRIX SWITCH

5.11.2 A

PCONCFGUTILITY

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.

CHAPTER 5: Configuration and Operation

5.11.3 A

PCONCMDUTILITY

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.

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 S

IGNALWIRING

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. Singleended 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.

CHAPTER 6: SCSI Technical Information

6.1.5 C

OMMONPROBLEMS

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 P

ASSIVETERMINATORS

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 A

CTIVETERMINATORS

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.

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.

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 Pin Number Signal Name Pin Number

Ground 1 -DB12 35

Ground 2 -DB13 36

Ground 3 -DB14 37

Ground 4 -DB15 38

Ground 5 -DBP1 39

Ground 6 -DB0 40

Ground 7 -DB1 41

Ground 8 -DB2 42

Ground 9 -DB3 43

Ground 10 -DB4 44

Ground 11 -DB5 45

Ground 12 -DB6 46

Ground 13 -DB7 47

Ground 14 -DBP 48

2 X 2 SCSI MATRIX SWITCH

Table 6-1 (continued). SCSI connector assignments for

single-ended (SE) 16-bit SCSI (wide).

Signal Name Pin Number Signal Name Pin Number

Ground 15 Ground 49

Ground 16 Ground 50

TERMPWR 17 TERMPWR 51

TERMPWR 18 TERMPWR 52

Reserved 19 Reserved 53

Ground 20 Ground 54

Ground 21 -ATN 55

Ground 22 Ground 56

Ground 23 -BSY 57

Ground 24 -ACK 58

Ground 25 -RST 59

Ground 26 -MSG 60

Ground 27 -SEL 61

Ground 28 -C/D 62

Ground 29 -REQ 63

Ground 30 -I/O 64

Ground 31 -DB8 65

CHAPTER 6: SCSI Technical Information

Table 6-1 (continued). SCSI connector assignments for

single-ended (SE) 16-bit SCSI (wide).

Signal Name Pin Number Signal Name Pin Number

Ground 32 -DB9 66

Ground 33 -DB10 67

Ground 34 -DB11 68

Table 6-2. SCSI connector assignments for

differential 16-bit SCSI (wide).

Signal Name Pin Number Signal Name Pin Number

+DB(12) 1 -DB(12) 35

+DB(13) 2 -DB(13) 36

+DB(14) 3 -DB(14) 37

+DB(15) 4 -DB(15) 38

+DB(P1) 5 -DB(P1) 39

Ground 6 Ground 40

+DB(0) 7 -DB(0) 41

+DB(1) 8 -DB(1) 42

+DB(2) 9 -DB(2) 43

+DB(3) 10 -DB(3) 44

+DB(4) 11 -DB(4) 45

2 X 2 SCSI MATRIX SWITCH

Table 6-2 (continued). SCSI connector assignments for

differential 16-bit SCSI (wide).

Signal Name Pin Number Signal Name Pin Number

+DB(5) 12 -DB(5) 46

+DB(6) 13 -DB(6) 47

+DB(7) 14 -DB(7) 48

+DB(P) 15 -DB(P) 49

DIFFSENS 16 Ground 50

TERMPWR 17 TERMPWR 51

TERMPWR 18 TERMPWR 52

Reserved 19 Reserved 53

+ATN 20 -ATN 54

Ground 21 Ground 55

+BSY 22 -BSY 56

+ACK 23 -ACK 57

+RST 24 -RST 58

+MSG 25 -MSG 59

+SEL 26 -SEL 60

+C/D 27 -C/D 61

+REQ 28 -REQ 62

CHAPTER 6: SCSI Technical Information

Table 6-2 (continued). SCSI connector assignments for

differential 16-bit SCSI (wide).

Signal Name Pin Number Signal Name Pin Number

+I/O 29 -I/O 63

Ground 30 Ground 64

+DB(8) 31 -DB(8) 65

+DB(9) 32 -DB(9) 66

+DB(10) 33 -DB(10) 67

+DB(11) 34 -DB(11) 68

Table 6-3. SCSI connector assignments for

low-voltage differential (LVD) 16-bit SCSI (wide).

Signal Name Pin Number Signal Name Pin Number

+DB(12) 1 -DB(12) 35

+DB(13) 2 -DB(13) 36

+DB(14) 3 -DB(14) 37

+DB(15) 4 -DB(15) 38

+DB(P1) 5 -DB(P1) 39

+DB(0) 6 -DB(0) 40

+DB(1) 7 -DB(1) 41

+DB(2) 8 -DB(2) 42

+DB(3) 9 -DB(3) 43

2 X 2 SCSI MATRIX SWITCH

Table 6-3 (continued). SCSI connector assignments for

low-voltage differential (LVD) 16-bit SCSI (wide).

Signal Name Pin Number Signal Name Pin Number

+DB(4) 10 -DB(4) 44

+DB(5) 11 -DB(5) 45

+DB(6) 12 -DB(6) 46

+DB(7) 13 -DB(7) 47

+DB(P) 14 -DB(P) 48

Ground 15 Ground 49

DIFFSENS 16 Ground 50

TERMPWR 17 TERMPWR 51

TERMPWR 18 TERMPWR 52

Reserved 19 Reserved 53

Ground 20 Ground 54

+ATN 21 -ATN 55

Ground 22 Ground 56

+BSY 23 -BSY 57

+ACK 24 -ACK 58

+RST 25 -RST 59

+MSG 26 -MSG 60

CHAPTER 6: SCSI Technical Information

Table 6-3 (continued). SCSI connector assignments for

low-voltage differential (LVD) 16-bit SCSI (wide).

Signal Name Pin Number Signal Name Pin Number

+SEL 27 -SEL 61

+C/D 28 -C/D 62

+REQ 29 -REQ 63

+I/O 30 -I/O 64

+DB(8) 31 -DB(8) 65

+DB(9) 32 -DB(9) 66

+DB(10) 33 -DB(10) 67

+DB(11) 34 -DB(11) 68

2 X 2 SCSI MATRIX SWITCH

Table 6-4. SCSI distance/device support.

STA Term Maximum Bus Length (M) Maximum Devices

SE HVD LVD

SCSI-1 6 25 — 8

Fast SCSI 6 25 — 8

Fast Wide SCSI 6 25 — 16

Ultra SCSI 1.5 25 — 8

Ultra SCSI 3 — — 4

Wide Ultra SCSI — 25 — 16

Wide Ultra SCSI 1.5 — — 8

Wide Ultra SCSI 3 — — 4

Ultra2 SCSI N/A 25 25 2

Ultra2 SCSI N/A 12 12 8

Wide Ultra2 SCSI N/A 25 25 2

Wide Ultra2 SCSI N/A 12 12 16

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).

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.

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.

1000 Park Drive • Lawrence, PA 15055-1018 • 724-746-5500 • Fax 724-746-0746

Black Box SC120A-R2, SC121A User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual