[GreenKeys] Replying to David

[NNN7DXB at aol.com]

David:

Quick history lesson, since you asked:

RY, SG, TE, Figs-Space all caused the selector levels of teletype machines
to move. Most common in the Army was RY, although I have seen the 
Navy use SG often. Some Army TTY maintainers used TE, Figs-Space 
and other combinations. The QBF test (Quick Brown Fox) contained all
the letters of the alphabet, so it was a popular test sentence.

The use of NNNN came about in 1942 when the first tape relay equipment
came into use. It was developed by Western Union to tell tape apes where
a message ended. Tape relay gear was the AN/TGC-1. 

The early tape relay gear was built for both the Army and the Navy during
the  WW II years to expedite the movement of large volumes of wartime
traffic. 

CW traffic often ended traffic with a single N or B.

To tell where messages began, WU developed the "ZCZC" letter combo.
It was odd enough and easily recognized and not likely to be misunderstood
for anything OTHER than a "symbol", much like NNNN (both developed about
the same time period).

Prior to NNNN being used, BBBB was used when several messages were
sent as a "string". The last message ended with NNNN to let the receiving
end know that the "string" of messages had ended. BBBB was only ever
used in point to point, switchboard-operated teletype systems, and never
in a tape relay operation.

Some would say that NNNN stood for "Nothing Follows", but there is no proof
of that. Others suggested BBBB stood for "More to Follow", but again,
no record of that either.

Both ZCZC (later VZCZC) and NNNN stayed in military use until about 2003
when AUTODIN finally gave way to DMS. Both VZCZC and NNNN still show
up in some military comms, even today. DMS is more like email, and less
like "true messaging", so none of these prosigns or symbols are used much
anymore.

Many commercial teletype operations later adopted the ZCZC and NNNN
routines, especially NEWS stations using RTTY in Europe. NATO militaries
also used them.

A variation of the ZCZC is VV   XXX###, or VV, 3 spaces, followed by the
Channel ID and Channel Number (VV   HNA001).

VV   XXX### was often used by US, UK and CAN military tactical CommCenters
over field circuits. The UK and CAN preceded these with UU or HH. UU =
denoted an Unclas message followed; HH was to let you know a classified
message was coming.

Dave