HP Laserjet III Series Connectivity

A customer brought me an HP Laserjet III, Laserjet IIId, and a laserjet IIIsi (he had bought them all at an auction)for cleaning, evaluation, and minor repair if necessary.

All three have Jetdirect cards installed, in addition to the serial and parallel ports, and will print beautiful self-test pages.

I need to make these work off of parallel, but for some reason they won’t respond. I tried removing the jetdirect port and testing to no avail. I don’t want to use the jetdirect (which is for Novell) or the serial. Any ideas?