24
4 X 2 SCSI MATRIX SWITCH
Table 5-2. Jumper settings for external termination
E19-Port A
E20-Port 1
E24-Port 3
E21-Port B
E22-Port 2
E26-Port 4
NOTE
The standard factory default connects internal terminators to internal
5 volts.
5.5 Serial Port Interface 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 daisy-chained ports.
Daisy-chained 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
5.6 Internal RS-232 Jumper Block
RS-232 P
ORT
1
Jumper block E9, E10, E1, E12, and E13 configure the Port 1 serial interface for
normal and null-modem serial cables. The SCSI Switch default configuration
operates with standard modem cables.
