Specifications

DeviceMaster Installation and Configuration Guide: 2000506 Rev. B Connecting Serial Devices - 59
DB9 Serial Cables and Loopback Plugs
DB9 Serial Cables and Loopback Plugs
You can build your own null-modem or straight-through DB9 serial cables for 1-port and
4/8-port models using the following subsections.
Note: See DeviceMaster 2-Port with Serial Terminals
on Page 56 for 2-port models with
DB9 connectors..
This illustrates the DB9 connector signals.
Note: If you are using a DB9 to RJ45 adapter, see RJ45 Serial Cables and Loopback Plugs
on Page 61.
DB9 Loopback Plugs Loopback connectors are DB9 female serial port plugs, with pins wired together as shown,
that are used in conjunction with application software (Test Terminal or minicom) to test
serial ports. The DeviceMaster is shipped with a a single loopback plug (RS-232/422).
Note: You can use Test Terminal (Windows) or minicom (Linux) to test the serial ports.
You can use the Support page on the CD shipped with the DeviceMaster or see
Locating Software and Documentation
on Page 10) to locate the NS-Link User Guide
for Windows or the Linux readme file.
Wire the following pins together to build
additional plugs or replace a missing RS-232
loopback plug:
• Pins 1 to 4 to 6
•Pins 2 to 3
• Pins 7 to 8 to 9
DB9 Connector Pinouts
Pin RS-232
†† RS-422 RS-485
1 DCD Not used Not used
2RxD RxD- Not used
3 TxD TxD- TRxD-
4 DTR Not used Not used
5 GND Not used† Not used†
6 DSR Not used Not used
7RTS TxD+ TRxD+
8CTS RxD+ Not used
9 RI Not used Not Used
† Pin 5 is tied to ground on the board, but is
not used in the cable.
†† The DeviceMaster Serial Hub only supports
RS-232.
Pin 1
Pin 6
DB9 Male
RS-232
RI
CTS
RTS
DSR
GND
DTR
TxD
RxD
CD
Pin 1
Pin 6
DB9 Male
RS-422
Not used
RxD+
TxD+
Not used
Not used*
Not used
TxD-
RxD-
Not used
Pin 1
Pin 6
DB9 Male
RS-485
Not used
Not used
TRxD+
Not used
Not used*
Not used
TRxD-
Not used
Not used
* Pin 5 is tied to ground on the board,
but is not used in the cable.
Pin 1
Pin 5
Pin 6
Pin 9
RS-232 Only
(Back View)
Pin 1
Pin 5
Pin 6
Pin 9
RS-232 Only
(Back View)
The RS-232 loopback plug
also works for RS-422.