Posts: 489
Threads: 11
Joined: Jan 2005
Is this an HP-97 or HP-97S? The 97S had an external BCD interface module that was connected by a cable that entered the calculator next to the power supply connector. The interface module had a 50-pin connector on it, but I believe the cable was connected (internally) with a 20-conductor connector. Later versions of the 97 used the same board as the 97S and had the solder pad for the cable inside. Perhaps there was a version of the 97S made with a detachable cable (though I've never heard of one), or perhaps you have a 97 that was retrofitted with a connector to attach to a 97S interface module. Does it look like the connector was facory installed, or a homebrew job?