Epson Apex 20020 - Manual (Page 190)

To perform the test, you must insert a special loop-back
connector into the parallel port so that the computer can
check the individual pins of the port. Contact your Customer
Care Center if you need a loop-back connector (or see
Appendix A for signal/pin assignments to make your own loop-
back connector). Note that a different connector is required to
test the serial port.
When you select option 9 from the DEVICE LIST, you see
these prompts:
Attach loop-back connector to parallel 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.
The computer checks the port by writing and reading dam and
control information, and reports errors for any pins that are
faulty. Note that if you connect a printer cable instead of a
loop-back connector, you get errors.
Parallel Port (on Video Adapter) Check
Use the Parallel port (on video adapter) check to test the
functions of the primary port. This tests either the built-in port,
if it is set up to act as the primary port, or the parallel port on a
monochrome adapter (such as the IBM monochrome display
and printer adapter) if you have one installed in your
computer.
To perform the test, you must insert the special loop-back
connector into the parallel port so that the computer can
check the individual pins of the port. This test is identical to
the Parallel port check. For more details, see the description of`
the Parallel port (printer interface) check above.