Comtrol RocketPort Universal PCI - Manual (Page 20)

20 - Connecting Serial Devices RocketPort Universal PCI User Guide: 2000284 Rev. G
Connecting Serial Devices
RJ11 Straight-
Through Cable (RS-
232) 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.
RJ11 Loopback
Plugs A loopback plug is an RJ11 serial port plug with pins wired together. You can use
it with application software (for example, Test Terminal) to test serial ports.
To build an RJ11 loopback plug, wire these pins together:
• Pins 3 to 4
• Pins 1 to 5 to 6
DTR 1
DCD
RxD
TxD
DTR
GND
Signal
DCD
RxD
TxD
GND
Signal
RJ11
5
4
3
2
Pins
DB25
8
3
2
20
7
Pins
RocketPort DCE Serial Device
DB9
1
2
3
4
5
Pins
CTS CTS 6 5 8