Black Box SC121A Manual De Usuario
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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 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.
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
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