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

The computer checks the port by writing and reading data and control information, and reports errors for any pins that are faulty.

Serial Port (RS-232C Port) 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 serial port so that the computer can check the individual pins of the port. Contact your dealer if you need a loop-back connector. Note that a different loop-back connector is required to test the parallel port.

When you select option 11 from the DEVICE LIST menu, you see this message:

SERIAL PORT CHECK

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.

D-22 Performing System Diagnostics