AT&T Unix PC Keyboard

[jsheradin]

I had the chance to mess with a board that I believe was originally for the AT&T 3B1 Unix PC. It features ITW magnetic valve switches and some nice dye sub keycaps. I mustered my inner MMcM and figured out a basic USB converter for it.

Spoiler:

The Pro Micro mount is held in with 3M VHB and doesn't require any cutting or other irreversible modifications.

In short, the protocol is 1200 baud, 7N1, inverted serial and sends 'frames' for every key event (press or release). Each frame contains a list of all keys currently pressed. All keys result in a frame being sent. All keys have a unique code in the frames. No codes change as a result of modifiers. In the event that all keys are released, a frame containing '@' is sent.

The firmware reads in a frame, compares it to the last one to see what changed, maps it with a massive switch statement, and sends the necessary codes through the keyboard library. The majority of the keycodes are just the character that the key corresponds to. Right now it's a rough proof of concept using the basic Arduino libraries but it seems to work great with no major quirks. Hopefully someone can build on it and port it to TMK/QMK but I didn't have it in me to figure out the registers and whatnot to enable serial.

Code, pinout, printable mount, and some more protocol info can be found here: https://github.com/jsheradin/ATT_3B1_KB_USB

Edit: I don't have the keyboard anymore to test but I believe it should be compatible with https://github.com/MMcM/qmk_firmware/tr ... convergent or a slightly modified version of it at least.

[Redmaus]

Dude really clean conversion, I love how you have a micro-USB port on a vintage board without cutting or gluing anything to the case.