Gcom Xray Monitoring Kit

To diagnose problems in the production environment without disrupting or dropping a connection, turn your Gcom® synchronous serial adapter into a real-time data line monitor using:

  • Gcom's line monitor test cable - Feeds data from either end into available ports on the Gcom four-port synchronous serial adapter.
  • Gcom Xray software - Passively examines a data stream in real time, monitoring both sides of a connection without interrupting the connection.

Step 1. Install the Gcom line monitor test cable.

The Gcom line monitor test cable has four ports. A short, thick, gray cable connects two data ports. A thin green or blue cable connects each data port to a monitoring port.

Use this diagram as a model for monitoring a connection sourced from the machine used for monitoring. This enables easy development of line error response applications that run independently of the protocol application.

Model Gcom line monitor test cable installation

Step 2. Configure Gcom Xray software.

The /usr/lib/gcom/xray directory contains the following files:

  • configs.xray - Configuration file for ports 3 and 4
  • configure.xray - Script to set up ports 3 and 4 for use by Gcom Xray software
  • README - Instructions for setting up the Gcom line monitor test cable
  • run.xray - Script to run Gcom Xray software

At the command line on a terminal connected to the device with Gcom's synchronous serial adapter:

  1. Enter: cd /usr/lib/gcom/xray
  2. Enter: ./configure.xray

Step 3. Monitor the data line.

Use the run.xray script:

To monitor: Enter the following at the command line:
X.25 packet level run.xray X.25 or run.xray x.25
SNA RUs run.xray SNA or run.xray sna
LAPB frames (X.25 frame level) run.xray LAPB or run.xray lapb
HDLC/SDLC frames (SNA data link layer) run.xray HDLC or run.xray hdlc
Bisync run.xray BISYNC or run.xray bisync


For more information on how to manipulate Gcom's Xray software:

  • Display Gcom_xray utility Help text - At the command line on a terminal connected to the device with Gcom's synchronous serial adapter, enter: /usr/bin/Gcom_xray -h
  • Or see the Gcom_xray - Manipulate trace information in Appendix A of the Streams Troubleshooting Guide.