Rj45 Null-Modem Cables (Rs-232); Rj45 Null-Modem Cables (Rs-422); Rj45 Straight-Through Cables (Rs-232/485) - Comtrol DeviceMaster LT User Manual

RJ45 Null-Modem Cables (RS-232)

RJ45 Null-Modem Cables (RS-232)

RJ45 Null-Modem Cables (RS-422)

RJ45 Straight-Through Cables (RS-232/485)

66 - Connecting Serial Devices
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.
Signal
TxD
RxD
RTS
CTS
DSR
DCD
DTR
GND
Note: You may want to purchase or build a straight-through cable and purchase a
null-modem adapter. For example, a null-modem cable can be used to
connect COM2 of one PC to COM2 of another PC.
Use the following figure if you need to build an RS-422 null-modem RJ45 cable. A
null-modem cable is required for connecting DTE devices.
Note: RS-422 pinouts are not standardized. Each peripheral manufacturer uses
different pinouts. Please refer to the documentation for the peripheral to
determine the pinouts for the signals above.
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 of one
PC to COM2 to a modem.
Signal
DCD
RxD
TxD or TRxD+
DTR or TRxD+
GND
DSR
RTS
CTS
RJ45
DB9
Pins
Pins
5
2
4
3
1
8
8
7
2
4
3
1
7
6
6
5
RJ45
Signal
Pins
TxD+ 5
TxD- 7
RxD+ 4
RxD- 2
GND 6
RJ45 DB9 RJ45
Pins Pins
Pins
1 3
3
2 4
4
5 3 5
7 4 7
5 6
6
2 6 2
7 1
1
8 8
8
DeviceMaster LT User Guide: 2000586 Rev. B
DB25 RJ45
Pins
Pins Signal
RxD
3
4
TxD
2
5
CTS
5
8
RTS
4 1
DTR
20 7
DCD
8
3
DSR
6
2
GND
7
6
Signal
RxD+
RxD-
TxD+
TxD-
GND
DB25
Pins Signal
8
DCD
3
RxD
2
TxD or TRxD+
20
DTR or TRxD+
7
GND
6
DSR
4
RTS
5
CTS