[GreenKeys] TTY protocol

[Duncan M. Brown]

"ZCZC" indicates "start of message" and was originally used in military TTY
torn-tape message relay stations.  "ZCZC" is like "RY" in that punches all
five holes and is easily identified by an operator or automatic equipment.

Likewise, "NNNN" was used to indicated the end of a message (maybe because
it sounds like "end"?).

I'll have to do some more research, but I believe these indicators were
first used by the AN/FGC-1 Tape Relay equipment in WWII.  They are still
used today, though in ASCII format by many automated message systems.

73 & have fun,

Duncan Brown, K2OEQ

Chief TTY operator & repairman
AWA Electronic Communication Museum
http://www.antiquewireless.org/


> [Original Message]
> From: Jerry Barnish <jrbarnish at DRPA.ORG>
> To: <greenkeys at mailman.qth.net>
> Date: 15-Aug-08 07:57:02
> Subject: [GreenKeys] TTY protocol
>
> Gentleman:
>  
> I am a ham for 33 yrs and am experienced with tty operations to a point
> of being
> just a bit past neophyte.
>  
> What is the meaning of "NNNN" and "ZCZC" at the ending of a message?
> I notice the long term users adding it and also on German Meteo msgs
> and have not yet taken the time to research it as of yet.
>  
> I also agree that the fascination of watching the units print has never
> become
> boring. The public has no appreciation of the history behind the units
> and I also agree that it needs to be preserved forever. 
> Fortunately, the Battleship New Jersey is giving me the opportunity to
> learn
> much more about teletype now then I did when I was active on local
> VHF nets in the 1980's.
>  
> Thanks for all of the infornation posted on this net.
>  
> Jerry WB2CAK 
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