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Parallel Port Testing

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  • Parallel Port Testing

    I'm looking for some software that will do a complete test on a parallel, EPP, ECP port. It seems that Burn In Test's loopback connector for the parallel port only connects pins 2, 3, 4, 5, 6, 10, 11, 12, 13, 15 of the DB25 connector. By definition, therefore, their loop-back test cannot test pins 1 (Strobe), 7 (Data 5), 8 (Data 6), 9 (Data 7), 14 (Linefeed), 16 (Reset), 17 (Select Printer) cannot be tested at all. If one of these pins were open circuit, or short circuit, or blown up or otherwise faulty, the test would not find it at all. What sort of a test is that? This is no use at all for me. How can I get a test that will fully test the port, i.e. test that all the pins that should be connected are connected, and are capable of going high and low, and being sensed correctly. For bidirectional pins I would like them to be tested in both directions.

    Thanks - Rowan

  • #2
    Yes, only the following pins are used the parallel port loopback plug

    DB-25 Pin Direction Description
    2 Out Data bit 0 (Least significant bit)
    3 Out Data bit 1
    4 Out Data bit 2
    5 Out Data bit 3
    6 Out Data bit 4
    10 In Acknowledge status
    11 In Busy status
    12 In Paper out status
    13 In Select status
    15 In Error status
    It has been a long long time since we looked at this. Maybe 15 years. But I seem to remember there was a good reason for not using some of the other pins. It might have been that on some machines it wasn't possible to drive some of these other pins and measure the response. Honestly I am not sure now. The parallel port was never designed as a data input device. It was originally output only, which limits its looping ability.