[GreenKeys] AN/FGC-38 Torn-Tape Relay Equipment

Mon Aug 28 11:41:27 EDT 2017

Hi Duncan:

FWIW, is was not feasible for, or even possible for a floor operator
in a tape relay to swap out one perforator for another during a tape
changing operation. An op could NOT do this. It would have required
access to a patch panel which was not necessarily on the relay floor.
Even a Trick Chief could not perform this operation, since a patch 
panel was usually located in the Tech Control area (or, for crypto gear
sparing over, in the crypto area).

A TTY repairman or someone in Tech Control would have had to
do this and there would have had to have been some sort of justification
to perform such a function. Changing a tape reel was not a good enough
reason, since that was "basic" operator responsibility. Only "demand
maintenance" such as equipment failure or malfunction would have
been acceptable. Swapping equipment was also a bit time consuming --
had to get someone to do it, then do it, and then see if it worked, etc....

As I said earlier, it was much easier to simply change tape reels "on
the fly" and send the distant end a "ZFX" service msg and be done with
it.....quick an dirty and that is how we did things.

Likewise, there was little space available on the relay floor for "spare"
teletype gear such as what you had in a large or busy tape relay. Most
relays were crammed full of equipment that was in full operation most
of the time. So, any equipment that broke down was most often repaired
immediately, on site, by a TTY repairman. Most TTY repair guys were
pretty good at it -- they could restore a piece of equipment back to
operation in only a few minutes by fixing or replacing a part. We used
Kleinschmidt equipmently in Army tape relays and this equipment was
very reliable....rarely ever broke down, and was maintained regularly
by the maintenance folks. In a relay, you always had TTY and crypto
repair people on shift along with the ops....and they generally "cruised"
the relay floor looking for potential problems.....and correcting them
if any were observed right away. Sometimes, the TTY maint guys
even helped out by changing a tape reel on a perforator or a printing
ribbon on a perforator if the ops were busy.....

The biggest problems with tape relay gear was dirt (tape residue in
TDs, and heat build up. A TD brush worked well to clean TDs which picked
up a lot of crud from oiled tape. Kleinschmidt equipment did not like
heat though, so we often operated the AN/FGC-70s and AN/TGC-5s
with thier covers open at times to allow the heat inside to escape.
A TD brush was simply a wide tooth brush! Perforators accumulated
gunk too from continuous tape punching, but these were easily blown
out of wiped off.....

As for the idea of an 8-hour prep time for a long Operational Immediate
message....I think that book author was pulling your leg ! (smiling).

On a long message like that, a couple of things might happen....

First, it was given to the fastest typing operator in the terminal section
(relays did NOT type messages; that function was performed in the Terminal
Section, if the relay had a terminal, which some did (and others did not).

Second, if the message was very long (i.e. page and pages), it might
be divided up between two or three "pokers" (guys who would type it up
to cut a tape). Once done, it was spliced to make one long tape.

If it was really, really long, then it was "sectioned" by the A&D clerk
and each section was a separate message and each section was
marked "Section ____ of Sections". Sections did not necessarily have
to be sent in sectioned order....they were sent when they were ready.

A&D: Acceptance and Delivery Clerk: This is the guy who accepted the
message at the CommCenters Service Window from the subscriber or
writer. His job was to log the message in (accept it), page it, section it,
assign the Routing Indicators, Julian Date and Filing Time and then
pass it on to the pokers. On the Delivery side, his job was to insure
that message copies were stamped with appropriate classifications,
precedence stamps, add cover sheets if necessary, log the messages
on the delivery register (for customer pick up and signature), and to
notify customers of traffic awaiting pick up the CommCenter. If additional
copies had to be made of the message in the case of multiple addressees,
he did that too. He had a phone and a copier and had his own desk
right at the Service Window....(sometimes, we used mimeograph machines
to make additional copies, but these were eventually replaced by copy 
machines in the 70s).

IN between time, this kind of operation did NOT stop all other traffic
from being sent or received. Traffic continued to flow and did not wait
on other traffic to be prepared or tapes to be cut.

Once the Immediate message was ready to go, we did not ordinarly
interupt a message already in the process of being transmitted. A message
already in progress being sent was allowed to be sent, and then the
Immediate message was next up to go....

Only FLASH (ZZ) messages would generally interupt another message
already in the process of being sent, or in later years, "Flash Override" (YY).

A message being interupted caused a "Cancel Transmission" slip to be

sent, aka "CT", aka "Bust".....this was usually something like this:

E E E E E E E E AR RUFM    (8 spaced "E" followed by the canceling stations RI and EOM)
BT

NNNN

and then, the Flash message would be sent. This way, Channel Numbers were
still accounted for. The Busted message would then be sent again after the
ZZ was sent. All bases covered! The cancelled message then became a formal
record and was logged as such on the send log, usually as a "CT" "C/T"or "ZFR".
(ZFR is a Z Signal meaning "Cancelled Transmission) (see ACP-131).

Most military messages were sent based on precedence and then the
FIFO method. FIFO = First In, First Out).

Dave

# # #

-----Original Message-----
From: Jim Haynes <jhhaynes at earthlink.net>
To: David F <nnn7dxb at aol.com>
Cc: pbirkel <pbirkel at gmail.com>; greenkeys <greenkeys at mailman.qth.net>
Sent: Mon, Aug 28, 2017 10:47 am
Subject: Re: [GreenKeys] AN/FGC-38 Torn-Tape Relay Equipment

Depending on traffic volume, an incoming line could have a "tape-changing
reperforator" assigned so it could be turned on when the regular reperf
was getting low on tape.

On another topic, there have been times when reality left the scene.
A book "United States Army in Vietnam.  Military communications, a test 
for technology"  by John D. Bergen tells of an incident - I'm relying on
memory now, rather than looking it up in the book - where a message was
started with Operational Immediate precedence, and the message was so 
large that it took something like 8 hours for the originating operator to 
punch into tape.  Meanwhile nothing of lower precedence could be sent 
because of the rules governing precedence.

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