[GreenKeys] Stock ticker saga ...

[jhaynes@alumni.uark.edu]

The Teletype square box ticker is of course one that works on start-stop
code, rather than the pulse counting code of the earlier ones.

Since I got back from a short trip I looked at some notes I have.  Looks
like most of them used separate circuits for the stepper and printer 
magnets, and that's why yours has four terminals.  The way I described,
where pauses in the reversals cause printing to happen, is the way the
signal is transmitted on a single wire from some distance away, and then
within the city they used two wires.

I have some scans of maintenance handbook pages I can send you - nothing 
about the machine itself, but shows the circuits.

After those were replaced by the Teletype ticker for stock market service
they continued in use until circa 1950 carrying baseball scores.  That's
the one I saw.

There is one reference in these notes to a  single-wire ticker.

I also have a transcript of a Western Union Technical Review article
by an old ticker man.  This is probably on the web already, but I can
send it to you if you can't find it.  Charles R. Tilghman is the
author.

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jhaynes at alumni dot uark dot edu