[GreenKeys] Western Union Technical Review

[John Nagle]

  I've been reading through Western Union Technical Review from 1947
to 1969:

http://massis.lcs.mit.edu/archives/technical/western-union-tech-review/

  There's a huge amount of technical detail there about how
the telegraph system worked in the heyday of Teletype machines.
The various switching systems, starting with Plan 1 for Morse
code lines and continuing through Plan 59 are described.
Many specialized devices were built that are forgotten today,
such as the "page printer control unit" which did automatic
word wrap for Teletype page printers.  There are detailed
discussions of the Kleinschmidt and Teletype Model 28
machines. (Reduced clutch wear was a big deal.)

  Slowly, electronics starts to appear.  First thyatrons
(nothing to burn out), then vacuum tubes, and finally transistors.
There's a lot of technology overlap; the final reperforator-based
systems had transistors in them.

   Interestingly, Western Union had a magnetic drum based system
as early as i955, but it was for inventory control and made by
Teleregister.

				John Nagle