You were asking about RS-232 for a Teletype; I was thinking, bring the
mountain to Mohammed (a 20mA interface on the computer), not the other way
around.
I have this mental image of using a PDP11/05 or similar with DL11 card (there is a
current loop serial inteface on the CPU board set in that machine, so a DL11 for
RS232) as an RS232 interface for a Model 33. It would work, I guess, but
'overkill' ;-)
[Mind you I did once use a PET 8032 to drive an HPIB plotter from an RS232 port.]
-tony