Lexmark 1020 - Manual (Page 29)

Diagnostic Aids 3-4
4078-00X
Parallel Port Test
This test performs a wrap around test between the printer parallel
port and the parallel port test connector.
This test requires a parallel port wrap plug. Install the wrap plug in
the parallel port before you start the test. The power on light flashes
if the test is successful. If the test is not successful, the power on
light remains off.
To run the test:
1. With a parallel port wrap plug installed and the printer off, press
and hold the following button while turning the printer on:
2. Paper Feed
After five seconds, release the button to begin the test.
The Power On light blinks upon successful completion of the test.
A failing test causes the Power On light to remain off. Turning the
power off or unplugging the printer ends the test.