[GreenKeys] Differences between US Army & Navy TTY communications

[Duncan Brown]

On Sat, Apr 8, 2023 at 7:43 PM Duncan Brown <duncanancy at earthlink.net> 
wrote:
 >Low-level signalling!  There is another variable and reason you can't put
 >TX & RX all on one loop.

On 08-Apr-23 21:04, Nick England wrote:
> Normal low-level connection was with the keyboard feeding one of two 
> inputs to the printer.
>

At first, I didn't understand Nick's statement.
But then I realized it is another Army/Navy, Kleinschmidt/Teletype Corp. 
difference.

A M28 KSR/ASR always had a an ESU with a local loop and a line relay for 
isolation from the line. So you could have a low level "loop" feeding 
the M28 and then the ESU converted the low level to high level to feed 
the selector magnets.

Kleinschmidt machines never included a isolating line relay. Except at 
the large comm centers, they normally connected directly to a wire line 
modem or FSK converter. A low-level TX signalling connection was made 
directly to to the crypto equipment which would typically be only a few 
away.  There was no low-level signalling on the RX side from the crypto 
gear. From the 1950s through the 1980s, crypto gear was KW-9 (until mid 
1960s), KW-7, & KW-26.

Duncan
K2OEQ
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20230409/26df3c4d/attachment.html>