Rj45 Null-Modem Cable (Rs-232); Rj45 Null-Modem Cable (Rs-422 Or Rs-485 Full-Duplex); Rj45 Straight-Through Cable (Rs-232 Or Rs-485 Half-Duplex); Rj45 Loopback Plugs - Comtrol RocketPort INFINITY User Manual

Connecting Serial Devices
RJ45 Null-Modem
Cable (RS-232)
RJ45 Null-Modem
Cable (RS-422 or RS-
485 Full-Duplex)
RJ45 Straight-
Through Cable (RS-
232 or RS-485 Half-
Duplex)
RJ45 Loopback
Plugs
18 - 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.
Use the following figure if you need to build
an RS-422 null-modem cable. A null-modem
cable is required for connecting DTE
devices.
Note: RS-422 pinouts are not standardized.
Each serial manufacturer uses
various pinouts. Please refer to the
documentation for the serial to
determine the pinouts for the signals in the previous picture.
Use straight-through cables to connect modems and other DTE devices. For
example, you can connect one end of a straight-through cable to COM2 on one
computer and the other end of the straight-through cable to a modem.
RocketPort
Signal
RS-232 RS-485HD
DCD
RxD
TxD TRxD-
DTR
GND
DSR
RTS TRxD+
CTS
RI
RocketPort INFINITY models with RJ45 connectors are shipped with
a a single loopback plug (RS-232/422).
Wire the following pins together to build additional loopback plugs or
replace a missing RS-232/422 loopback plug:
• Pins 4 to 5
• Pins 1 to 8
• Pins 2 to 6 to 7
Wire the following pins together for an RS-422 loopback plug:
• Pins 4 to 5
• Pins 1 to 8
RocketPort
RJ45
Signal
Pins
TxD 4
RxD 5
RTS 1
CTS 8
DSR 7
DCD 6
DTR 2
GND 3
RocketPort
Signal
TxD+
TxD-
RxD+
RxD-
DCE Serial Device
DB25
RJ45 DB9
Pins
Pins Pins
8
6 1
3
2
5
2
3
4
4 20
2
7
3 5
6 6
7
4
7
1
5
8 8
N/A 22
9
RocketPort INFINITY User Guide: 2000465 Rev. G
DTE Serial Device
DB9
DB25
Pins Signal
Pins
2
3
3
2
8
5
7
4
4
20
1
8
6 6
5
7
DTE Serial
Device
RJ45
Pins
Signal
1 RxD+
4 RxD-
8 TxD+
5 TxD-
Signal
RS-232 RS-485HD
DCD
RxD
TxD TRxD-
DTR
GND
DSR
RTS TRxD+
CTS
RI
RS-232/422
RxD
TxD
CTS
RTS
DTR
DCD
DSR
GND