[GreenKeys] Fwd: AN/TGC1

[jhhaynes at earthlink.net]

Whether it's worth picking up is a matter of opinion.

Quick background - torn-tape switching is what you have when you
receive messages on a reperforator and tear off the tape at the
end of the message and carry it to a tape transmitter sending toward
the destination.  Some torn-tape switching centers have a whole
wall of reperforators receiving from the various lines and then
a bank of transmitters sending to all the lines.  A different concept
is the "packaged" torn-tape switch where the reperforators and
tape readers are combined in cabinets so you can build a switching
center of any desired size by using enough of them and practically
nothing else.  The AN/TGC-1 is such a beast, built by Western Union
for the Army in WW-II.  The cabinet holds two typing reperforators
and a three-headed multiple transmitter-distributor MXD.

Normally the equipment operates at 60 wpm but it could be operated
at 100 wpm as a matter of war necessity - they decided that the
higher speed was worth the extra maintenance and wear on the
machinery.  TGC-1 requires a couple of capacitors be added for
100 wpm operation; TGC-1A has these added already.  In either case
some mechanical parts have to be changed when changing speeds.
Then there is a TGC-1B that is arranged to shut the motors off when
there is no traffic.  Some of the units have synchronous motors but
most have governed motors since the military in the field doesn't
have well regulated 60 HZ power.

They can be set up to operate in a variety of ways, polar or neutral
circuits, full or half duplex, one or two circuits.  If it is set up
for one circuit, then it receives on one reperforator and the other
is used as a monitor or to receive while tape is being changed in
the main reperf.  Two of the transmitter heads transmit alternately
to the same line; and the third head is for a reel of message number
tape so it sends a message number ahead of each message.  If it is
set up for two circuits then each reperf receives from one circuit
and each of two transmitter heads feeds one circuit.

If somebody offered me one I would take it, but then I'm a nut case
when it comes to switching equipment.  Most of the units in the past
got taken apart for the reperforators and the tape transmitters and
the rest was junked.  The cabinet is 2 feet square by 5 feet 5 inches
high and weighs 250 pounds without the TTY equipment installed.




jhhaynes at earthlink dot net