[GreenKeys] Replying to David

[sdaitch at kuw.ibb.gov]

We could have used ZCZC as well, or for that matter any character sequence
which did not usually occur in message traffic.  Our net was a three hour
per day schedule with 6 stations, and totally manual, other than the
tape punches using the SOM and EOM sequences.

Our RTTY traffic was administrative in nature, and in order to facilitate the
traffic schedule, the sending stations would make up a master tape for the
days traffic, using the SOM and EOM cues, but between messages, about ten LFs
to divide up the page copy and that would also allow the receive operation
a moment to pull the tape through the puncher, so we had a foot or so of clean 
tape with only the sprocket feed on the chadless punchers.


We were a small budget operation....in fact, still are!

73
Sheldon

----- Original Message -----
From: NNN7DXB at aol.com
Date: Thursday, September 30, 2010 5:38 pm
Subject: Re: [GreenKeys] Replying to David

> Hi Sheldon:
> 
> The ZCZC and NNNN discussion of which I spoke earlier was in fact
> quite different from your take.
> 
> Mine was for a (strictly) tape relay operation - no typing online 
> and NO
> keyboards on tape relay equipment. In a tape relay, all you had were
> rows and rows of tape machines spitting and sending tape (no page 
> copies).(As we used to say in the military tape relays: you 
> "pulled" and "pushed"
> tape (pulled = received; pushed = sent). Often you were waist deep 
> in the
> stuff. The noise and the heat from the machines was overwhelming at
> times, and the smell of hot oil was everywhere.
> 
> The initial idea probably had to do with the fact that the AN/TGC-1s
> used chadless tape in the early 1940s. The concept of "tape relay" was
> brand new, and tape apes were, for the most part, inexperienced. The
> concept of mass volume teletype traffic in tape form was new and it
> was evolving.
> 
> The ZCZC and NNNN were simply visual flags to let tape handlers 
> (tape apes)
> know where one message ended and another (a new one) began in 
> the tape stream, since all tapes would otherwise come in one after 
> another,usually without a pause,  "stop", QSL or other manual 
> intervention between
> messages. There was no automation in those days, and few, if any,
> automatic machine functions.
> 
> Western Union had the contracts for the Army and Navy in those years
> and that is the system they came up with. 
> 
> The WU/military system proved highly reliable and was carried forward
> into the AUTODIN years where computer equipment at AUTODIN Switching
> Centers was programmed to (also) look for the ZCZC (VZCZC) and NNNN
> functions. These later became known as Start of Message (SOM) 
> indicatorsand End of Message (EOM) indicators. (WU also had the 
> AUTODIN contracts
> and was the principle contractor in most WW II and later fixed-station
> communications installations).
> 
> Cheers,
> 
> Dave
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