[GreenKeys] Jack Selection for TTY equipment

[Jim Haynes]

I'd say 1/4" two-conductor tip-sleeve plugs and jacks are the most
traditional.  However three-conductor plugs and jacks are probably
easier to find.  If you use 2-conductor jacks with the sleeve being
metal with a metal nut you have to mount them on an insulating panel
or use insulating washers in oversize holes.  You can find jacks where
the outer housing is plastic so the sleeve is insulated from the
panel nut; that way you can mount them on a metal panel.

Another scheme which I have long promoted but which I'm not currently
using much is to put a loop-to-RS-232 converter on each machine, and
then you can handle the RS-232 level signals like audio signals.
But it turns out you need conventional loops here and there, especially
on the test bench.

The advantage of the RS-232 approach is that you can connect things
in parallel rather than in series; and by using diode gates you can
have essentially a hub where all the senders send to the hub and
all the receivers receive from it.

jhhaynes at earthlink dot net