Project: IBM Model M 1985

When my favourite electronics shop closed down, the owner invited me to the shop’s basement to see if I wanted anything since he was going to throw it away. I spotted this Model M 122 key terminal edition from 1985! It was covered in dirt — literal dirt. The moment I pressed a key I knew I wanted this thing as my main keyboard.

I noticed that instead of a normal AT/XT or PS/2 plug it had this weird RJ45 connector, which turned out to be for a terminal… We’ll revisit this later.

So, I started the arduous process of cleaning the beast. Since I didn’t have the required socket to unscrew its bolts, I cleaned the case in place with a wet, soapy toothbrush. The keys were also soaked in soapy water and individually wiped down and rinsed.

Initially I tried to make an adapter using a spare RJ45 keystone jack I had and a PS/2 → USB dongle, but quickly found out this keyboard was, in fact, not PS/2. When I plugged it in it kept repeating keys and acting weird.

After researching a bit more I found a project called the Soarer’s converter, which should work with this keyboard. It uses an Arduino Pro Micro and can even run QMK/VIA. The end product didn’t look that great but it has worked perfectly for years — so I don’t mind :P For anyone else looking to modernize their IBM keyboard, here’s a list of the connectors IBM used and their protocols:

• RJ45
  • Terminal
• 5-pin DIN
  • PC/XT
  • AT
• 6-pin mini-DIN
  • PS/2

This is the end result: My endgame keyboard (BLÅHAJ approved) + a bonus sound test ;)