Comtrol RocketPort EXPRESS - Manual (Page 13)

RocketPort EXPRESS User Guide: 2000481 Rev. E Connecting Serial Devices - 13
DB9 Straight-Through Cables (RS-232 or RS-485 Half-Duplex)
DB9 Straight-
Through Cables (RS-
232 or RS-485 Half-
Duplex) Use the following figure if
you need to build an RS-
232 or RS-485 half-duplex
straight-through cable.
Straight-through cables
are used to connect
modems and other DTE
devices. For example, a
straight-through cable can
be used to connect COM2
of one PC to a modem.
Note: RJ45 connectors are
not standardized.
Refer to your serial
device documentation for signal information.
DB9 Loopback Plugs RocketPort EXPRESS models with DB9 connectors on
the interface are shipped with a a single loopback plug
(RS-232/422).
Wire the following pins together to build additional
plugs or replace a missing RS-232/422 loopback plug.
• Pins 1 to 4 to 6
• Pins 2 to 3
• Pins 7 to 8 to 9
Wire these pins together if you want to build an RS-422 (only) loopback plug.
• Pins 2 to 3
• Pins 7 to 8
DB9
1
2
3
4
5
8
6
7
Pins
DCD
RxD
TxD or TRxD-
DTR
GND
CTS
DSR
RTS or TRxD+
Signal
DB9
1
2
3
4
5
8
6
7
Pins
DCD
RxD
TxD or TRxD-
DTR
GND
CTS
DSR
RTS or TRxD+
Signal
RI 9 9 RI
DB25
8
3
2
20
7
5
6
4
Pins
22
RocketPort DCE Serial Device
Pin 1 Pin 5
Pin 6 Pin 9
RS-232/422 (Back View)