[GreenKeys] Whazzit? Normal Input Keying (NIK)

[Jim Haynes]

sometime in the 1970s I got involved in buying government surplus stuff.
>From McClellan AFB I once acquired a TD stepping and regenerative repeater
facility.  This was 3 racks of equipment, each with dual redundant power
supplies and baud rate generators.  The TD steppers were in modules and
each module handled something like 16 TD or keyboards.  The Model 28 
manuals show sets of parts to be used for "synchronous pulsed" operation.
The regenerative repeaters were in individual modules, transistorized
but with polar relays for output.

I know the crypto designers are smart people, but it seemed pretty
dumb to me that they had to resort to pulsing the character sources.
Also they had a requirement for 7.42 code, couldn't handle 7.00 code.
This came up in connection with a Teletype time-division multiplexer
product.  This had to run faster than the incoming signals to be sure
it would not fall behind, since there was no buffering.  The start-stop
output was about 2% faster than normal, done by shortening the stop
pulse.  The multiplex would insert a pause every 50 characters or so
as it got ahead of the input character stream.  For non-encrypted
material this was never a problem.  But with encryption the crypto
equipment required 7.42 code, so there was a thing called a "Printing
Telegraph Signal Normalizer" TSEC/HW-1 which stretched out the received
characters to the desired length, and also generated blank characters
if there was no traffic.