Juni: A one-handed, 12-key chorded keyboard
wiki.xxiivv.com
wiki.xxiivv.com
I eyeballed the frogpad, and kept eyeballing it until they went out of business. Should have just bought one.
(1978, vs. 1992.)
A form is still on sale as the CyKey: https://sites.google.com/site/cykeybellaire/
I have one. I found it almost unusable myself, because the instructions and the alphabet are intended for right-handed use. I am left-handed so for me the mnemonics make no sense, and the instruction manual devotes just a single paragraph to sinistrals, saying (summarised) "just mirror everything".
Impressive design, nice hardware, but for me, too RH-centric. Like almost all modern cameras, for example, which are virtually impossible for southpaws to hold or to use.
A (as far as I know) universal chording system for both reading and typing has existed for a long time now: Braille. I think if I'd really need to learn a chorded keyboard system, I'd go for that. Maybe with some alterations to enable a one-handed setup, perhaps with foot pedals.
Does anyone have experience with that versus different chorded keyboards?