Comtrol RocketPort EXPRESS - Manual (Page 16)

16 - Connecting Serial Devices RocketPort EXPRESS User Guide: 2000481 Rev. E
DB25 Null-Modem Cables (RS-422 or RS-485 Full-Duplex)
DB25 Null-Modem
Cables (RS-422 or
RS-485 Full-Duplex) Use the following figure if you need to build an
RS-422 or RS-485 full-duplex null-modem
cable. A null-modem cable is required for
connecting DTE devices.
Interface boxes have optional pins available
for these signals. Refer to
Interface Box
Signals on Page 15 for more information.
Note: RS-422 and RS-485 signals are not
standardized and each serial
manufacturer uses different pinouts. Refer to the serial device
documentation to determine the pinouts for the signals above.
DB25 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.
DB25M: Fan-out
Cable Loopback
Plugs RocketPort EXPRESS models with DB25 male connectors on the interface are
shipped with a a single loopback plug (RS-232/422).
Wire the following pins together to build additional
RS-232/422 plugs or replace a missing RS-232/422
loopback plug.
• Pins 2 to 3
• Pins 4 to 5 to 22
• Pins 6 to 8 to 20
You can wire the following pins together for an RS-422 only loopback plug.
• Pins 2 to 3
• Pins 4 to 5
DB25F: Standard
Interface Box RocketPort EXPRESS models with DB25 female connectors on the interface box
are shipped with a a single loopback plug (RS-232/422).
Wire the following pins together to build additional
RS-232/422 plugs or replace a missing RS-232/422
loopback plug.
• Pins 2 to 3 or alternately, Pins 25 to 17
• Pins 4 to 5 to 22 or alternately, Pins 19 to 15 to 22
• Pins 6 to 8 to 20
You can wire the following pins together for an RS-422 only loopback plug.
• Pins 2 to 3 or alternately, Pins 17 to 25
• Pins 4 to 5 or alternately, Pins 15 to 19
TxD+
TxD-
RxD+
Signal
DB25
4
2
5
Pins
RxD+
RxD-
Signal
TxD+
TxD-
RxD- 3
RocketPort DTE Serial
Device
DB9
1
2
3
4
5
8
6
7
Pins
DCD
RxD
TxD or TRxD-
DTR
GND
CTS
DSR
RTS or TRxD+
Signal
DB25
8
3
2
20
7
5
6
4
Pins
DCD
RxD*
TxD* or TRxD-
DTR
GND
CTS*
DSR
RTS* or TRxD+
Signal
RI 22 9 RI
DB25
8
3
2
20
7
5
6
4
Pins
22
RocketPort DCE Serial Device
* Interface boxes have alternate pins available for this signal.
Refer to Interface Box Signals for more information.
Pin 13 Pin 1
RS-232/422 (Back View)
Pin 14 Pin 25
Male
Pin 13 Pin 1
RS-232/422 (Back View)
Pin 14 Pin 25
Female