Serial Port (RS-232C) Check

Use this option to test the functions of the primary serial communications (RS-232C) port. To perform the test, you must insert a special loop-back connector into the RS-232C port so that the computer can check the individual pins of the port. Contact your Customer Care Center if you need a loopback connector (or see Appendix A for the signal/pin assignments if you want to make your own loop-back connector). Note that a different connector is required to test the parallel port.

When you select option 11 from the DEVICE LIST, you see these prompts:

Attach loop-back connector to serial port. Enter Y to start this check when connector is attached, or Enter N to return to the menu.

Insert the loop-back connector. Then press Y and Enter to start the check.

First, the computer checks the serial port control lines to see that they are able to change from high to low and vice versa. No messages are displayed during this part of the test unless an error occurs.

The second test is an echo back check during which the port sends data to itself in a fixed data format, at all the possible baud rates. When this test begins, you see these messages:

RS232C echo back check - at various baud rates Current baud rate is 75

Current test data is 00

Each baud rate is tested in turn, and the progress is displayed. If the port does not become ready correctly, a timeout error occurs. If any data received does not match the data sent, a verify error occurs, and the computer reports the transmitted and received data at the time of the error.

Performing System Diagnostics

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