Appendix C. Cables
C–6
25-Pin-to-25-Pin (COM2)
The 25-pin-to-25-pin (COM2) cable—which you must
provide—connects to the MCS COM2 port through a
25-pin D-shell male and to an MCS workstation.
Note
You cannot use the COM1 cable to connect to the
COM2 port without using a 25-to-9-pin adapter.
When building your own 25-pin-to-25-pin (COM2) cable,
use no more than 50 feet (15.2 meters) of Belden
9612/9613 computer cable, or equivalent.
Table C–3 lists the pin assignments for the COM2 port on
the MCS and a corresponding 25-pin connector.
Table C–3. 25-Pin-to-25-Pin Null Modem Connection Pin Assignments
25-Pin Function
Description
25-Pin
Function
Description
2
TxD
Transmit data
→
3
RxD
Receive data
3
RxD
Receive data
→
2
TxD
Transmit data
4
RTS
Request to send
→
5
CTS
Clear to send
5
CTS
Clear to send
→
4
RTS
Request to send
7
SG
Signal ground
→
7
SG
Signal ground
20
DTR
Data terminal ready
→
6
DSR
Data set ready
8
DCD
Data carrier detect
6
DSR
Data set ready
→
20
DTR
Data terminal ready
8
DCD
Data carrier detect