It's a brand new Maxi-Switch MAX II keyboard, made about 1979. From the press release, https://www.computerwoche.de/a/max-tast ... ms,1193136, poorly translated out of German by myself:
Essentially it's an industrial keyboard which generates ASCII. (Mine doesn't have the serial attachment.)The MAX II has the same form factor as the MAX I, also are the plugs compatible. The keyboard works with a Intel-Microcomputer 8048 (or the programmable 8748), the scanning-signal for the 60 keys together generating the corresponding US-ASCII codes. For each squeezed key the corresponding code strikes the exit in parallel or in RS232 serial. Because of that the possibilities of this keyboard --- cry [the manufacturers] --- will be labelled as intelligent.
Embarrassingly, it took me until I got it home and unwrapped it before I realised that the layout was a bit familiar; it's the spitting image of a BBC Micro keyboard. The only difference is that the backtick/pound sign code is generated by shift-@ rather than shift-underscore.
This suggests that the BBC MIcro layout wasn't made up by Acorn --- it's a copy of an existing mainframe layout. This keyboard was made in 1979ish, at which time Acorn was working on the System 3 and the Atom, which had a related but different layout. This suggests that someone had exposure to whichever mainframe my keyboard is copying while doing the BBC/Proton industrial design. And I've also found some very similar Happy Hacking layouts, which corroborates this: http://xahlee.info/kbd/i/happy_hacking_ ... 447832.jpg
So I reckon this is a standard, if an obscure one. Anyone know where this came from? If the layout originally came from a mainframe terminal keyboard, it'd be interesting to know how the Acorn engineers got exposure to it...
(Well, I'd find it interesting.)