[GreenKeys] Polar Relay

[Harold Hallikainen]

As usual, Jim Haynes has provided extremely interesting information on
what was going on inside Teletype. Jim, you mention DEC came up with the
UART. Before I discovered the UART, probably about 1970, I put a whole
series of 8 bit parallel load serial out shift registers in series. I used
a diode matrix to convert the BCD output of a digital clock to Baudot,
then shifted the whole thing out to a model 15. Then I discovered the
General Instrument AY5-1013. Later I used the 6402 (maybe Intersil?) which
did not require a -12V supply. I do see at
https://en.wikipedia.org/wiki/Universal_asynchronous_receiver-transmitter#History
that Gordon Bell at DEC made the first UART. When I started developing
stuff with the MC6802, I used the 6551 UART since it had an internal bit
rate generator while the Motorola part did not.

Thanks for the great info, Jim. I had not thought about the history of the
UART in a long time.


Harold
https://w6iwi.org