Rj45 Serial Cables And Loopback Plugs; Rj45 Null-Modem Cables (Rs-232) - Comtrol DeviceMaster Up Hardware Installation Manual

RJ45 Serial Cables and Loopback Plugs

RJ45 Null-Modem
Cables (RS-232)
Connecting Serial Devices
You can build your own null-modem or straight-through RJ45 serial cables using
the following subsections.
Pin
1
2
3
4
5
6
7
8
*Pin 3 is tied to ground on the board, but is not
used in the cable.
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.
RS-232 RS-422
RTS TxD+
DTR Not used
Signal GND Not used*
TxD TxD-
RxD RxD-
DCD Not used
DSR Not used
CTS RxD+
RJ45
DB9
Pins
Pins
4
2
5
3
1
8
8
7
7
4
6
1
2
6
3
5
DeviceMaster UP User Guide: 2000451 Rev. C - 29
RJ45 Serial Cables and Loopback Plugs
RS-485
TxD/RxD+
Not used
Not used*
TxD/RxD-
Not used
Not used
Not used
Not used
DB25
RJ45
Pins Signal
Pins
RxD
3 5
TxD
2 4
CTS
5
8
RTS
4
1
DTR
20
2
DCD
8
6
DSR
6
7
GND
7
3