Comtrol Hub DeviceMaster - Manual (Page 95)

DeviceMaster Installation and Configuration Guide: 2000594 Rev. A Connecting Serial Devices - 95
Connecting Serial Devices
RJ45 Null-Modem
Cables (RS-422) 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.
RJ45 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 of one
PC to COM2 to a modem.
RJ45 Loopback
Plugs Loopback connectors are RJ45 serial port plugs with pins wired together that are
used in conjunction with application software (Test Terminal for Windows or
Minicom for Linux) to test serial ports. The DeviceMaster is shipped with a a
single loopback plug (RS-232/422).
• Pins 4 to 5
• Pins 1 to 8
• Pins 2 to 6 to 7
Note: You can use Test
Terminal (Windows) or
minicom (Linux) to test
the serial port. You can refer to
Testing Ports Using Test Terminal on Page
156 for Windows systems.
Device
Ma
ster
TxD+
TxD-
RxD+
Signal
RJ45
1
4
8
Pins
Fe
ma
le RxD+
RxD-
Signal
RxD- 5
TxD+
TxD-
GND 3 GND
Dev
ic
e
Master
DB9
1
2
3
4
5
8
6
7
Pins
DCD
RxD
TxD or TRxD-
DTR
GND
CTS
DSR
RTS or TRxD+
Signal
DCD
RxD
TxD or TRxD-
DTR
GND
CTS
DSR
RTS or TRxD+
Signal
Fe
mal
e
RJ45
6
5
4
2
3
8
7
1
Pins
RJ45
6
5
4
2
3
8
7
1
Pins
DB25
8
3
2
20
7
5
6
4
Pins
1 8
Plug
Top View
Cable
The RS-232 loopback plug also
works for RS-422.