[GreenKeys] Information Pleeze

[jhhaynes at earthlink.net]

Just to amplify what Don said - the line/test key is to allow you to 
operate the machine locally, keyboard and printer, or keyboard, tape
and printer, for testing.  The line shunt relay is to be sure the
communication line is shorted when the machine is turned off or when
some part of it is removed for maintenance work.  TTY lines are
normally in a closed-circuit state with current through them, and
should never be left open.

Also, not to disagree too much with what Don said, but the Army had
plenty of radioteletype, altho all the services used wire lines
whenever they could.  The SCR-299, the famous mobile set with the
Hallicrafters BC-610 transmitter, I believe was CW and AM phone
only; but its successors like the SCR-399 were equipped for RTTY.
There was a long lineage of these radio sets in shelters that were
portable RTTY stations.


jhhaynes at earthlink dot net