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

Mon Aug 28 11:03:17 EDT 2017

In my nearly two years aboard the USS Hancock, the only 28 equipment I ever saw was a number of 28 KSRs and
a 28KTR, typing reperf.  Never saw any other form of tape gear, just that KTR.  Never saw a MOdel 28 TD until
I had been a ham for a few years.

Most of the incoming tapes were made on Model 14 reperfs.  When the 'pink' started to show, we knew that we had some
period of time to get out a fresh roll and get it in place.  Far too often, this occurred in the middle of something
rather long, and we had two choices:  'double feed' the reperf, close to the end of the tape, and catch the wrath of
the TTY repairman, since this often caused the 14 to fail, or get creative and with two pair of hands, if available,
have the fresh roll leading edge ready to follow the last of the ending roll, with high hopes of losing just a few
characters.  With 'hard copy' available it was not necessarily a disaster, but if it was part of a "PYTHON" message,
loss of a single character might require that we request a 'resend' of that message, and be better prepared the
second time.

I don't remember if the 28KTR was capable of a 'double feed' when changing from a roll end to a new roll.  I suspect
that it was.  And, when you consider that many 'loop tapes' were created by overlapping a few characters (usually
LTRS) and slowly pulsing it through a TD a few times to get all of the 'chads' well overlapped and so the tape would
flow through the TD with no problem.  

Anyone else have memories of this kind of activity?  I was aboard the Hancock from May, 1959 through my release in
March of 1961.  

Ralph - W8ROI

- - - - - - - -

On Aug 28, 2017, at 9:52 AM, Duncan Brown wrote:

> Paul,
> 
> You said " a real challenge to get from the receiver to another transmitter without a snarl-up"
> When a message came in, it would be torn off of the reperforator (hence the term "torn tape relay") and walked (or tossed) to a tape reader bank for re-transmission.
> 
> Although I did hear of a story of a tape relay center where a high priority message came in that had to be relayed to multiple addressees immediately. So the tape came out of the reperforator and was fed directly into a tape reader and then, sequentially into other tape readers. But that was not the norm.
> 
> 
> Your "running out of tape in the middle of a message " question is a good one, that I never thought about before.  I never worked in a big tape relay center, but helped build & test a transportable one for the Army.  I think the answer is that there would be a bank of reperforators and when one started showing the end of tape, it would be switched off-line and another would be switched/patched into that circuit.
> 
> A roll of tape would last about 5 hours at 60 wpm and about 3 hours at 100wpm.
> 
> 
> On the ALL CAPS of the early machines - the generic name for your M15 (and earlier units) was a "printing telegraph" (Teletype Corp used this term up into the mid 1950s).  The main user of the early TTYs was Western Union & other telegraph companies and they started replacing their telegraph circuits with TTYs. But a message might travel through both Morse and TTY circuits. The Morse telegraph code did not have lower case letters, so there was no need for the printing telegraphs to have them, either.
> 
> 
> AT&T bought the Teletype Corp in 1930 to have machines to lease out for their new TWX (TeletypWriter eXchange) service. (In Europe, it was known as TELEX.) This service allowed TTY users to communicate with anyone else on the AT&T TWX network, just like the telephone exchange service.  Tell your daughter that your M15 is the _original_ e-mail device!
> 
> Have fun,
> 
> Duncan Brown, K2OEQ
> USASA  31J30
> 
> Antique Wireless Association Museum Asst. Curator, Commercial Equipment
> (also Chief TTY operator & repairman)
> http://www.antiquewireless.org/
> 
> On 28-Aug-17 02:39, Paul Birkel wrote:
>> 
>> Thanks Dave.  More great info!  A “couple of hundred feet” would seem to be a real challenge to get from the receiver to another transmitter without a snarl-up.  What’s to preclude “over-running” the pink tape-end-coming-soon indicator and having a tape run-out before a message completes?  Just monitor the receipt, accept that sometimes this will happen (like various categories of receiver mechanical problems) and ask for a retransmit should that happen?  Did the sectioning policy manage to avoid this, by keeping the tape-length for a section less than the pink-length?  Under heavy traffic conditions how long would a tape-roll last and how did you manage to avoid running out of tape mid-message?
>> 
>> (And, alas, I was never able to get my Morse Code proficiency up to the point of passing a radio license exam as a kid.  Now it’s all “ancient history” …)
>> 
>> One aspect of all of this has been the realization (understanding) of why USMTF looks the way it does, SCREAMING CAPS :->.  I grew up with a 33ASR (and minicomputers) in the 70’s and simply didn’t know of the earlier Baudot era.  Store-n-forward packet-switching was the new-thing for computer-communications then.  Its heritage from an earlier technology was either unreported, or I simply missed it in my education.
>> 
>> This whole earlier era is an eye-opener for me.  I’m pleased to report that I’ve recently become the proud recipient of an M15 and table that was passed along from another list member, so it’s no longer “just academic” :->.  I’ve not yet gotten to the point of putting it into service, but it’s an absolutely amazing piece of equipment to examine close up.  Had a bit of show-n-tell with my adult daughter last month.  Even as a “still life”.
>> 
>> Thank heaven for Greenkeys!
>> 
>> 
> 
> 
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