Comtrol RocketPort Universal PCI - Manual (Page 18)

18 - Connecting Serial Devices RocketPort Universal PCI User Guide: 2000284 Rev. G
Connecting Serial Devices
RJ45 Straight-
Through Cables Straight-through cables connect modems to other DCE 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.
The following image displays the pinouts for an RS-232 straight-through cable.
Note: If your RJ45 wiring differs from the one shown above, adjust the RJ45
pinouts accordingly.
RJ45 Loopback
Plugs A loopback plug is an RJ45 serial port plug with pins wired
together. You can use loopback plugs with application
software (for example, Test Terminal) to test serial ports.
To build an RJ45 loopback plug, wire the following pins
together:
• Pins 4 to 5
• Pins 1 to 8
• Pins 2 to 6 to 7
Ro
ck
et
P
o
rt
DB9
1
2
3
4
5
8
6
7
Pins
DCD
RxD
TxD
DTR
GND
CTS
DSR
RTS
Signal
DCD
RxD
TxD
DTR
GND
CTS
DSR
RTS
Signal
RI 9
RJ45
6
5
4
2
3
8
7
1
Pins
N/A
DB25
8
3
2
20
7
5
6
4
Pins
Customer DCE
22 RI