Allen-Bradley MicroLogix 1400 User Manual page 80

Chapter 4 Communication Connections
66
MicroLogix 1400 Channel 0 to Modem Cable Pinout
When connecting MicroLogix 1400 Channel 0 to a modem using an RS-232
cable, the maximum that the cable length may be extended is 15.24 m (50 ft).
DTE Device
(MicroLogix
1400
Channel 0)
8-Pin
7 TXD
4 RXD
2 GND
1 B(+)
8 A(-)
5 DCD
6 CTS
3 RTS
ATTENTION: Do not connect pins 1 and 8. This connection will
cause damage to the RS-232/485 communication port (channel 0)
of the MicroLogix 1400 and/or the controller itself.
Constructing Your Own Modem Cable
If you construct your own modem cable, the maximum cable length is 15.24 m
(50 ft) with a 25-pin or 9-pin connector. Refer to the following typical pinout for
constructing a straight-through cable:
AIC+ Optical Isolator
or 1766-LEC Channel 2
9-Pin
3 TXD
2 RXD
5 GND
1 CD
pins 4 and 6
4 DTR
are internally
6 DSR
connected for
1766-LEC only
8 CTS
7 RTS
TXD
RXD
GND
DCD
DTR
DSR
CTS
RTS
Rockwell Automation Publication 1766-UM001I-EN-P - June 2015
DCE Device
(Modem,
PanelView,
etc.)
25-Pin 9-Pin
2 3
3 2
7 5
8 1
20 4
6 6
5 8
4 7
Modem
25-Pin 9-Pin
TXD 2 3
RXD 3 2
GND 7 5
CD 8 1
DTR 20 4
DSR 6 6
CTS 5 8
RTS 4 7