[GreenKeys] First stock ticker debuts 1867

[Jim Haynes]

On Wed, 14 Nov 2018, Nick wrote:

> Was that particular machine and later ticker tape machines also based on 5
> bit baudot code?
> 
It's not a dumb question.  The earlier tickers worked on a stepping 
principle to rotate the type wheel.  One pulse for A, two for B, and
so on until the wheel was completely rotated.  So this was a pretty
inefficient use of line time compared to Morse or Baudot encoding.

The "black cube" ticker made by Teletype was introduced about 1930 and
used a six-bit code with start-stop synchronization.  The printing
mechanism was similar to the Model 26 printer, involving a type wheel
and a cylindrical array of stops to halt the rotating wheel at the
right place.  Western Union had a similar Baudot tape printer called
the 401A.  I'm not sure if these were a new product or if they were
made from recycled stock tickers.  They used mostly the same parts.