Db9 Null-Modem Cables (Rs-232); Db9 Null-Modem Cables (Rs-422); Db9 Straight-Through Cables (Rs-232/485) - Pepperl+Fuchs ICDM-RX/TCP-DB9/RJ45-PM Installation And Configuration Manual

ICDM-RX/TCP Installation and Configuration Guide

DB9 Null-Modem Cables (RS-232)

7.1.1. DB9 Null-Modem Cables (RS-232)
Use the following figure if you need to build an RS-232 null-modem cable. A null-modem cable is required for
connecting DTE devices.
Note: You may want to purchase or build a straight-through cable and purchase a null-modem adapter.

7.1.2. DB9 Null-Modem Cables (RS-422)

Use the following figure if you need to build an RS-422 null-modem cable.
Note: RS-422 pin outs are not standardized. Each peripheral manufacturer uses different pin outs. Refer to
the peripheral documentation to determine the pin outs for the signals above.

7.1.3. DB9 Straight-Through Cables (RS-232/485)

Use the following figure if you need to build an RS-232 or RS-485 straight-through cable. Straight-through
cables are used to connect modems and other DCE devices. For example, a straight-through cable can be
used to connect COM2 to a modem.
DB9
Signal
Pins
TxD 3
RxD 2
RTS 7
CTS 8
DSR 6
DCD 1
DTR 4
SIG GND 5
DB9
Signal
Pins
TxD+ 7
TxD- 3
RxD+ 8
RxD- 2
SIG GND 5
DB9
Signal Pins
1
DCD
2
RxD
3
TxD or TRxD-
4
DTR
5
SIG GND
6
DSR
7
RTS or TRxD+
8
CTS
RI 9
DB9
DB25 RJ45
Pins
Pins Signal
Pins
RxD
2
3 5
3 TxD
2 4
8 CTS
5
8
RTS
7 4
1
DTR
4
20 2
DCD
1
8 6
DSR
6 6
7
SIG GND
5
7 3
Signal
RxD+
RxD-
TxD+
TxD-
SIG GND
RJ45
DB9 DB25
Pins Pins Signal
Pins
6
1 8
DCD
2 5 3
RxD
3 4
2
TxD or TRxD-
4 2
20
DTR
5 3 7
SIG GND
6 7 6
DSR
7 1
4
RTS or TRxD+
8
8 5
CTS
N/A
9 22 RI
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