About 4 or so years ago (I can't believe it's been that long, I think it was late 2022) I got a few old keyboards off eBay. For the largest one I managed to find an adapter tutorial , however deskthority's unfortunately fell apart over the past couple years so it's not of too much use anymore. I managed to make my own adapter following the pictures and information provided, but many of the switches and internals on that board are rusted out so only a couple keys actually ended up working. Eventually I might gut it or just attempt a repair, I'll probably post on here if it ever happens.
This keeb is something interesting, I believe it's got an IBM 3270 layout; as I said it's been a while so bear with me while I re-learn everything about it. It started out as a complete mystery to me, it has as lock on the outside which connects to a dial and speaker; I imagine it'd be used to enable/disable a clicker function which is so common on 70's/80's keyboards. It has a DB-9 pinout with only 5 actual pins (-_-;) and while it did come with a cable the other end is a db-25 parallel-port looking connector with also only 5 pins so I have nothing I can try it on.