Db9 Null-Modem Cables (Rs-232); Db9 Null-Modem Cables (Rs-422); Db9 Straight-Through Cables (Rs-232/485) - Comtrol DeviceMaster EIP Series Hardware Installation And Configuration Manual

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.

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.

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.
DeviceMaster EIP | UP Hardware Installation and Configuration Guide: 2000633 Rev. C
DB9
Signal
Pins
TxD 3
RxD 2
RTS 7
CTS 8
DSR 6
DCD 1
DTR 4
GND 5
DB9
Signal
Pins
TxD+ 7
TxD- 3
RxD+ 8
RxD- 2
GND 5
DB9
Signal Pins
1
DCD
2
RxD
3
TxD or TRxD-
4
DTR
5
GND
6
DSR
7
RTS or TRxD+
8
CTS
RI 9
DB9
DB25
RJ45
Pins
Pins Pins Signal
RxD
2
3 5
3 TxD
2
4
8 CTS
5
8
RTS
7
4
1
DTR
4
20 2
1 DCD
8
6
DSR
6 6
7
5 GND
7
3
Signal
RxD+
RxD-
TxD+
TxD-
GND
DB9 RJ45 DB25
Pins
Pins Pins Signal
1 6
8
DCD
2 5
3
RxD
3 4 2
TxD or TRxD-
4 2 20
DTR
3
5 7
GND
6 7 6
DSR
7 1
4
RTS or TRxD+
8 8 5
CTS
N/A
9 22 RI
Connecting Serial Devices
Connecting Serial Devices - 37