IBM M Keyboard

A couple weeks ago, I managed to snag the holy grail of computer keyboards off of eBay, an IBM M keyboard, for a really good price. What I didn't realize is that there are so many different versions of it ;) The one I wound up with is the 122 key terminal keyboard with a 5 pin DIN connector. Except the DIN connector isn't the same as the PC/XT/AT connector. The pins are spaced further apart and have a different layout. The good news is the these keyboards have a header connector inside them for the cable, so it's easily replaced. The bad news is that when connected to a PC with a replacement cable (or adapter) they act as an 84 key keyboard, wasting all those extra keys. But there's an adapter that I can build to use it with USB, allowing me to map all those extra keys. I can build this adapter externally, or mount it inside the keyboard itself. Alternatively, I can build something similar using a Pi Zero, putting an entire PC inside the keyboard. I think I like the idea of the external adapter better, though, as is allows me to add Num, Caps, and Scroll Lock LEDs, which this version of the keyboard lacks, and also allows up to five external buttons as well.