

I know for sure that the Everex Magic I/O EV-170A can be jumpered
for a printer mode, or for a general purpose bidirectional I/O mode.

Also, I know for sure that the IBM Technical Reference says the following
about the Monochrome Display & Printer Adapter and the IBM Parallel Printer
Adapter:

    It is essential that the external device not try to pull these
    lines [referring to the data lines] to ground.

And later:

    If an external device should be driving data on these pins (in
    violation of usage ground rules) at the time of an input, this
    data will be `or'ed with the latch contents.

I will accept no responsibility if you incur damages of any kind
as a result of my saying, ``I DO NOT know for sure, but I think
you should be able to use a traditional parallel port as an input
port by writing 0x to the data lines, and then reading from the
data lines, while an external device drives them.''  The input
data will not be latched, so noise could make this infeasible.