[GreenKeys] Projectors

[jhaynes@alumni.uark.edu]

According to Walt Zenner, Teletype first made projectors using Model 15s
for the Navy.  The application was on aircraft carriers, where the noise
level in the pilots' ready room was such that they could not hear a verbal
briefing.  So the Navy requested a Teletype machine with a projector to
present the material visually.  An interesting problem with Model 15
technology was that the machine wasn't designed to operate on a pitching,
rolling ship.  They had to modify it with a counterweight to the type
basket to get reliable carriage return in a ship.

Another military application of the projector sets was secure 
conferencing.  TTY transmissions could be encrypted much more easily
than voice; so it was possible to have several people participate in
a conference using a projector to display the text for all in one
location to see.

This was one of the considerations that led to the Model 28 being designed 
to operate in any position.  One of the sales fixtures was a Model 28
typing unit mounted on gimbals so they could demonstrate it operating
in any position.  Because of this feature, the initial production of
Model 28 equipment all went to the military, mainly to the Navy.

There was a projector using a Model 28 that replaced the one using a
Model 15.

Quite likely Trans-Lux did make a projector.  It would have been easy to
do using a Teletype stock ticker, having it print on cellophane rather 
than on paper, and then pull the cellophane through a projection light
source and lens.

Later Trans-Lux made the flipping ball kind of dot-matrix display used in
brokerage offices to display stock market transactions on the wall.  Since
this was basically a dot-matrix display they needed a ROM to translate the
ticker code (modified Baudot) into dot patterns.

When Walt Zenner retired from Teletype he got hooked up with an 
acquaintance who wanted to make stock tickers.  These were to be 
programmable to print just a few selected stocks rather than the entire
market.  Trans-Lux bought the design, having visions of installing
tickers in private offices and homes for use by individuals interested
in following a few stocks.  But the market didn't develop and the machines
were not produced in quantity.

However Zenner and his associate went on to make a dot-matrix teleprinter,
taking advantage of the Baudot-to-dot ROM chip made by Texas Instruments
for Trans-Lux.  They named their company Extel and went on to sell a lot
of machines to press wire services, beginning with Reuters.  This may have
been the first dot-matrix teleprinter.