What does it take to convert a Teletype 3320 with the
telex modem to
do 20 ma current loop?
An ex-Telex machine (which this may or may not be) is likely to be a
5-level (not 8 level) machine, and therefore a Model 32 at heart.
Converting that to a Model 33 would involve replacign a lot of mechanical
parts.
If it is an 8 level machine, then AFAIK all the 'mechancial modules' are
the same no matter what interface/modem is installed (other than the fact
that there are 2 keyboards, one generates parity, the other doesn't). As
such. the difference is the call control unit, the electronics chassis to
the right of the machine. The one for current loop operation is quite
simple, and you could probably make it fromn scratch if you had to.
-tony