Each PXS is factory-tested before shipping. However, you should perform the following tests before starting your development with the LayGO Toolkit (if you are a developer) or before using your application program (if you are an end user).

The LayGO PXS Toolkit setup program installed the necessary test files and programs in your Start menu.

Before running any of the tests, make sure you have installed and configured the PXS and have entered the correct IP address in the LayGO system stack configuration. If you changed the default (, use wxedcfg to modify the stackpxs.cfg configuration file.

Internal Loopback Test

Simply click Start → Programs → LayGO PXS Toolkit → WinTdrv - Loop.

(For a detailed explanation of the WinTdrv program, see Testing with tdrv in the LayGO Installation Guide.) You will see the following window:

WinTdrv Openning Screen
WinTdrv Opening Screen

The top left dialog shows that the program will use line 0, which corresponds to synchronous port 0 on the PXS (later you will use the drop down list to change it to line 1, corresponding to the synchronous port 1 on the PXS).

Now, do the following:

If you have any trouble during this procedure, check the Troubleshooting section.

External Loopback Test

This test verifies that the PXS line drivers and receivers are correct, as well as the interface cable.

Connect the synchronous interface cable to the PXS. Connect the appropriate loopback plug to the connector. (The LayGO Hardware Guide has detailed diagrams of loopback plugs.)

Now click Start → Programs → LayGO PXS Toolkit → WinTdrv - Source

Repeat the same procedure indicated above, for Internal Loopback. The test is similar but now data is going out through the cable and back from the loopback plug to the PXS. If this test works correctly, the cable and the line drivers and receivers are OK.

Back-to-Back Test

This test should be run only if the internal loopback test ran successfully. It can only be run on a PXS with 2 lines.


Connect the PXS's 2 synchronous ports in a back-to-back fashion: Use a DB-26 to DB-25 straight cable (P/N CBL-PXS-26/25-1) connected to each port and an RS-422/EIA-530 null modem cable. (See the Null Modem Cables section of the LayGO Hardware Guide.) Alternatively, you may interconnect the 2 ports using a "crossover cable" (P/N CBL-PXS-XOVER).


Now, you will use two instances of WinTdrv program. One will drive port 0 (which will be configured as clock source) and the other port 1 (which will be configured as clock sink).

Start the first instance by clicking Start → Programs → LayGO PXS Toolkit → WinTdrv - Source. Start the second instance with Start → Programs → LayGO PXS Toolkit → WinTdrv - Sink.

In the last wintdrv, change the line in the upper left corner drop down list to 1.

WinTdrv two instances
Two instances of WinTdrv

Now do the following:

If you have problems performing this procedure, the Troubleshooting section may help.