Epson Equity II - Manual (Page 128)

Parallel Port (Printer Interface) Check
Use this option to test the operation of the primary parallel printer port.
To perform the test, you must insert a special loop-back connector into the
parallel port so that the computer can check individual pins of the port.
Contact your dealer if you need a 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 data 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 will get errors.
Parallel Port (on Video Adapter) Check
Use this option to test the operation of an additional parallel port. To
perform the test, you must insert the special loop-back connector into the
parallel port on the video adapter so that the computer can check individual
pins of the port.
This test is similar to the Parallel Port Check. For more details, refer to
the description of the Parallel Port (Printer Interface) Check.
Serial Port (RS-232C) Check
Use this option to test the functions of the primary serial communi-
cations (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
individual pins of the port. Contact your dealer if you need a loop-back
connector. Note that a different connector is required to test the parallel
port.
Diagnostics 4-21