Comtrol Cable - Manual (Page 11)

Building Cables for RocketPort Products [Documentation number: 2000430 Rev B] 11
DB9 Loopback Plugs
DB9 Loopback Plugs A loopback plug is a DB9 female serial port plug with pins wired together. You can
use it with application software (for example, Test Terminal) to test serial ports.
This topic describes the following DB9 loopback plugs:
• An RS-232 loopback plug is shipped with the following models: RocketPort
PCI, RocketPort Universal PCI and RocketPort ISA.
• An RS-422 loopback plug is shipped with the following models: RocketPort PCI
422, RocketPort Plus PCI 422 and RocketPort Plus Universal PCI 422.
RS-232 Female
Loopback Plug The Quadcable and Octacable use the RS-232 female
loopback plug. To build a loopback plug for the Quadcable
and Octacable, wire the following pins together:
• Pins 1 to 4 to 6
• Pins 2 to 3
• Pins 7 to 8 to 9
Note: Ring Indicator (RI) is only supported on Quad/Octacable cards.
RS-422 Loopback
Plug To build a DB9 loopback plug, wire the following pins together:
• Pin 2 to 8
• Pin 3 to 7
DB9 Null-Modem
Cables You need a null-modem cable to connect to DTE devices. For example, you can
connect one end of a a null-modem cable to COM2 on one computer and the other
end of the null-modem cable to COM2 on another computer. All RocketPort models
support DB9 null-modem cables.
RS-232 Null-Modem
Cable The following image displays the pinouts for an RS-232 null-modem cable.
Note: You can also attach a null-modem adapter to one end of a straight-through
cable to create a null-modem cable.
RS-422 Null-Modem
Cable The following image displays the pinouts for an RS-422 null-modem cable.
Important: RS-422 pinouts are not standardized. Each peripheral
manufacturer uses different pinouts. Please refer to the document
for the peripheral device to determine the pinouts for the signals
above.
Pin 1 Pin 5
Pin 6 Pin 9
RS-232 (Back View)
RocketP
o
rt
TxD
RxD
RTS
CTS
DSR
GND
DCD
DTR
Signal
RxD
TxD
CTS
RTS
DTR
GND
DCD
DSR
Signal
DB9
2
3
8
7
4
5
1
6
Pins
DB25
3
2
4
7
8
6
Pins
20
5
DB9
3
2
7
8
6
5
1
4
Pins
Customer DTE
RocketP
o
rt TxD+
TxD-
RxD+
Signal
DB9
7
2
3
Pins
RxD+
RxD-
Signal
TxD+
TxD-
RxD- 8
Customer DTE