[GreenKeys] 750 wpm Teletype in 1956 - AN/FGC-36

[Harold Hallikainen]

Really interesting! I have only skimmed the manual. It's interesting that
there are separate type wheels instead of just a big cylinder of type.
But, I guess if the type wheels are pushed up against each other, the
result is a cylinder.

I'm guessing that the type "cylinder" is rotating behind the paper, and
the ribbon and hammers are in front of the paper, so the character is
printed from the back of the paper.

I did not see what order the characters were on the print cylinder. If
they were in Baudot order (with another bit for shift), there could just
be a binary counter that keeps track of the cylinder position and triggers
the hammer when the binary code of the received character lines up with
the current cylinder position. Did the unit buffer a whole line of
characters, then hit all the hammers during one rotation of the cylinder?
I see it could be pretty fast that way.

This also seems similar to chain printers. I see there were also band
printers that were similar and could do 3,000 lines per minute (
https://share.google/aimode/oPcN92OTPl98CWs8R ).

The AN/FGC-36 looks pretty compact, but the electronics are not! Amazing
stuff!

Harold
https://w6iwi.org





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