for anything useful?

Apple provided this as their mouse, keyboard, etc, interface vehicle on the earlier MacIntosh models. I hope they've outgrown that by now, but, since I found (and purchased) a keypad that might acutally fit my needs, on eBay some time ago,

I thought I'd inquire as to whether anybody here has ever messed with that interface. It's similar in some ways to the IBM Keyboard protocol, in that it has two lines of which one is a bidirectional (?) clock and the other is bidirectional data driven with an open-drain driver. Details are sketchy, however, and apparently presented by committee. Any three sources will yield four explanations of how it works.

This particular keypad has a 24-poin 805x part in it. I was hoping, of course, to find a version of that part that could be substituted, thereby giving me control of what it does. That was a dead-end, though.

RE