Rockwell Automation 1771-DMC_DMC1_DMC4_DXPS Control Coprocessor User Manual - Manual (Page 276)

Cable Connections
Appendix C
C-3
Table C.B provides the pin assignments for the 25-pin COMM1,
COMM2, and COMM3 (/t1, /t2, /t3) ports on the main and serial
expander modules.
Table C.B
Pin Assignments for 25ĆPin COMM1, COMM2, and COMM3 Ports
Pin RSĆ232C RSĆ422A RSĆ423 RSĆ485
1 C.GND C.GND C.GND C.GND
2 TXD.OUT TXD.OUT TXD.OUT RESERVED
3 RXD.IN RXD.IN RXD.IN RESERVED
4 RTS.OUT RTS.OUT RTS.OUT RESERVED
5 CTS.IN CTS.IN CTS.IN RESERVED
6 DSR.IN DSR.IN DSR.IN RESERVED
7 SIG.GND SIG.GND SIG.GND SIG.GND
8 DCD.IN DCD.IN DCD.IN RESERVED
9 RESERVED RESERVED RESERVED RESERVED
10 NOT USED DCD.IN ′ NOT USED NOT USED
11 RESERVED RESERVED RESERVED TXRX
12 RESERVED RESERVED RESERVED RESERVED
13 NOT USED CTS.IN ′ NOT USED NOT USED
14 NOT USED TXD.OUT ′ SEND COM NOT USED
15 RESERVED RESERVED RESERVED RESERVED
16 NOT USED RXD.IN ′ REC COM NOT USED
17 RESERVED RESERVED RESERVED RESERVED
18 RESERVED RESERVED RESERVED RESERVED
19 NOT USED RTS.OUT ′ NOT USED NOT USED
20 DTR.OUT DTR.OUT DTR.OUT RESERVED
21 RESERVED RESERVED RESERVED RESERVED
22 NOT USED DSR.IN ′ NOT USED NOT USED
23 NOT USED DTR.OUT ′ NOT USED NOT USED
24 RESERVED RESERVED RESERVED RESERVED
25 RESERVED RESERVED RESERVED TXRX'
Connecting to the 25ĆPin
COMM1, 2, and 3 Ports