Db9 Loopback Plugs; Connecting Db9 Serial Devices - Comtrol DeviceMaster MOD Series Hardware Installation And Configuration Manual

Connecting Serial Devices

DB9 Loopback Plugs

Connecting DB9
Serial Devices
48 - Connecting Serial Devices
Loopback connectors are DB9 female serial port plugs with pins wired together
that are used in conjunction with application software to test serial ports. The
DeviceMaster is shipped with a a single loopback plug (RS-232/422).
Not all DeviceMaster MOD and DeviceMaster UP protocols provide test (example
programs). Modbus/TCP User Guide
programs.
The following DeviceMaster MOD and DeviceMaster UP protocols do not use the
loopback plug:
• Modbus Router
• Modbus Server
Wire the following pins together to build additional plugs or replace a missing RS-
232 loopback plug:
• Pins 1 to 4 to 6
Pin 1
• Pins 2 to 3
• Pins 7 to 8 to 9
Wire the following pins together for an RS-422 loopback plug:
• Pins 2 to 3
• Pins 7 to 8
You can use this information to connect serial devices to DB9 connectors.
1. Connect your serial devices to the appropriate serial port on the DeviceMaster
using the appropriate cable.
Note: Refer to the hardware manufacturer's installation documentation if you
need help with connector pinouts or cabling for the peripheral device.
2. DeviceMaster 4-port: verify that the devices are communicating properly.
Note: DeviceMaster 1-port, 2-port models, and
the 4-port DIN models do not have TX/RX
LEDs.
The RX (yellow) and TX (green) LEDs function
accordingly when the cable is attached properly to a serial device.
• After power cycling the DeviceMaster (appropriate models), the RX/TX
LEDs are off.
• The LEDs do not function as described until the port has been opened by
an application.
3. You can refer to Network and Device LEDs
the remaining LEDs.
DeviceMaster MOD | UP Hardware Installation and Configuration Guide: 2000630 Rev. B
for information about using those example
Pin 5
RS-232 Only
(Back View)
Pin 6 Pin 9
Pin 5
Pin 1
Pin 6 Pin 9
The RS-232 loopback plug
also works for RS-422.
RS-422 Only
(Back View)
on Page 89 for information about