Hardware reference guide

Modbus Plus NOMs
35013379 02 October 2007 289
Modbus
Connector
Pinouts
The NOM modules are equipped with a nine-pin RS-232C connector that supports
Modicon’s proprietary Modbus communication protocol. The following figure shows
the Modbus port pinout connections for 9-pin (left) and 25-pin (right) connections.
6
IBM-AT
9-Pin Female
Quantum
9-Pin Male
Quantum
9-Pin Male
IBM-XT
25-Pin Female
CD
RX
TX
DTR
GROUND
DSR
RTS
CTS
1
2
3
4
5
6
7
8
1
2
3
4
6
7
8
9
SHIELD
RX
TX
DTR
GROUND 5
DSR
RTS
CTS
NC
1
2
3
4
7
8
9
SHIELD
RX
TX
DTR
GROUND 5
DSR
RTS
CTS
NC
RX
RTS
CTS
DSR
GROUND
NC
1
2
3
4
5
6
7
8
SHIELD
TX
20DTR
This document provided by Barr-Thorp Electric Co., Inc. 800-473-9123 www.barr-thorp.com