Paul Koning wrote:
PLATO 3 used reed switches, and I believe PLATO IV did likewise.
Liquid proofing is clearly a good reason: those systems were intended
for use by students (of all ages) and were certainly likely to have
beverages spilled on them. Because of how they were built, a good
scrub under hot water would fix them right up.
Jos Dreesen wrote:
Tektronix also used this. The Tek 4014 has such a keyboard.
Thanks, I went looking for photos of Plato terminals but it's difficult to tell from
the limited resolution of the ones I found. I'll keep on the lookout for photos of
Plato,CDC and Tektronix terminals.