29 Jan
2014
29 Jan
'14
11:17 a.m.
I don?t remember ever seeing a Model 33 with parity.
And weren?t
They exist, sort of. From what I've seen and read :
All Model 33 'Typing Uniuts' -- the printer -- expect 8 bits, of which
the high bit is ignored. so you can send them 7 bits with an odd or even
parity bit and they will work. Pairty is not checked.
The punch and reader of the ASR33 handle all 8 bits. That is, the
incoming parity bit will be punched on the tape (it is not checked) and
the parity bit punched on the tape will be read and transmitted. In a
sense they are '8 bit clean'
The keyboard exists in 2 versions. One always sens a '0' for the parity
bit. The other one, which can be recognised by an extra switch contact
block, sends even parity.
I think one of my Model 33s does have the 'parity keyboard'.
-tony