Keebin’ with Kristina: the One With the Duplex Typewriter

Keebin’ with Kristina: the One With the Duplex Typewriter

The Coleco Adam? A not-so-great home computer that likely contributed to the downfall of the company. The keyboard, however, is a different story, and worth repurposing.


[Nick Bild] has created a USB adapter that uses a Teensy 4.1 and an RJ-12 breakout board. Now this wasn’t just a simple matrix to decode. No, the fine folks at Coleco rolled their own communications protocol called AdamNet.


The keyboard uses an RJ-12 connector and a single data line to communicate over a 62.5 kbit/s, half-duplex serial bus. Inside the keyboard is a Motorola 6801 that caches the key presses and sends them to the computer. So the BOM is limited to what you see above — an RJ-12 breakout and a Teensy 4.1. It’s great to see old keyboards come alive again, especially one with such cool sci-fi keycaps. Want to hear it clack? Of course you do.



Typewriters vs. ADHD


Russell Watson of Sunshine Coast Typewriters. Image via ABC News Australia

Do you know how long it took me to write Keebin’ this time around? Do you know how much faster it would have been if I’d typed it on a typewriter? Yeah. This is totally a thing. It seems typewriters are all the rage among Australian teenagers, especially those with ADHD.< ..

Support the originator by clicking the read the rest link below.