Comtrol WCom2 - Manual (Page 23)

Port Monitor and Test Terminal User Guide: 2000485 Rev. B Using Test Terminal - 23
Using Test Terminal
You can use the following procedure to test COM ports. If you need to install the
RocketPort, RocketModem IV, or DeviceMaster device driver, go to
ftp://ftp.comtrol.com/html/default.htm to locate the latest driver and driver
installation documentation.
The following procedures require a loopback plug to be placed on the port or ports
that you want to test. A loopback plug was shipped with your product. If you need
to build a replacement or additional loopback plugs, refer to the appropriate User
Guide for your RocketPort, RocketModem IV, or DeviceMaster. See
Locating
Comtrol Tools and Product Documentation on Page 6 if you need to build loopback
plugs.
Overview
Test Terminal (WCom2) allows you to open a port, send characters and commands
to the port, and toggle the control signals. This application can be used to
troubleshoot communications on a port-by-port basis.
• Send and Receive Test Data: This sends data out the transmit line to the
loopback plug, which has the transmit and receive pins connected thus
sending the data back through the Rx line to Test Terminal, which then
displays the received data in the terminal window for that port. This test is
only testing the Tx and Rx signal lines and nothing else. This test works in
either RS-232 or RS-422 modes as both modes have transmit and receive
capability. A failure in this test will essentially prevent the port from working
in any manner.
• Loopback Test: This tests all of the modem control signals such as RTS, DTR,
CTS, DSR, CD, and RI along with the Tx and Rx signals. When a signal is
made HI in one line the corresponding signal line indicates this. The Loopback
Test changes the state of the lines and looks for the corresponding state
change. If it successfully recognizes all of these changes, the port passes.
A failure on this test is not necessarily critical as it will depend on what is
connected and how many signal lines are in use. For example, if you are using
RS-232 in 3-wire mode (Transmit, Receive and Ground) a failure will cause no
discernible issue since the other signals are not being used. If the port is
configured for use as either RS-422 or RS-485 this test will fail and is expected
to fail since RS-422 and RS-485 do not have the modem control signals that
are present in RS-232 for which this test is designed.