[GreenKeys] an interesting oddity

[Jim Haynes]

I don't know any interesting stories.  Western Union operated a lot of
time-division multiplex until about 1950, using motor-driven faceplate
distributors and elaborate means for keeping them in synchronism.
21-A printers were used on the receiving ends.  The machine appears
to be a Kleinschmidt design.  In the early days of amateur RTTY, the
early 1950s, hams were desperate to get any kind of printer and some
obtained 21-A machines.  I believe there were some start-stop receiving
distributors available, perhaps from Model 12s, that could be used to
drive the 21-As.  A ham in Southern California designed an electronic
receiving distributor.  I had a 21-A printer and built the electronic
distributor but never got it to work.