[GreenKeys] Why and When 7.00 vs. 7.42 unit code?

[Duncan Brown]

Nick,

I've been wondering about 7.42 vs 7.00. (& 8.00) also.

US Army Signal Corps (KLI) used both also.  But KW-7 & KW-26 crypto 
units worked with 7.42 codes.

Seemingly identical units would be available in both codes under 
different numbers, so it was apparently important to keep them 
separate.  For example, the AN/FGC-25 & -26 (KLI's "ASR") was supplied 
with 7.42 code. But the seemingly identical AN/FGC-52 & -68 used 7.00 
code from the tape reader and 8.00 code from the keyboard.

I always assumed it was some computer equipment that couldn't handle a 
fractional data bit.  Maybe Autodin?? (I believe that Autodin used 
AN/FGC-161, -162 (low level signaling version of the FGC-25) machines. 
But lthe FGC-161 was 7.42 and the FGC-162 used 8.00 from the keyboard & 
7.00 from the tape reader.)

I would think it would be hard to sync on a 7.00 code??

Another good mystery to work on!!

73,

Duncan
K2OEQ
USASA  31J30


On 10-Mar-14 08:09, Nick England wrote:
> OK, I understand 7.00 unit code means you can run a bit faster, but 
> who used it in practice and in what circumstances?
>
>  I understand WU was all 7.00 - is this right?
>
> Looking at the Navy's list of TTY units, there were both 7.00 and 7.42 
> unit machines galore - how was it decided what to use where? Were all 
> on-line crypto machines 7.00 or some systems were 7.42 and some were 
> 7.00? Or what? What about Signal Corps gear?
>
> Was there just a break and after July 17, 1958 all new Bell 
> installations used 7.00 or whatever? Or was this decided on a case by 
> case basis - and what was the basis?
>
> Thanks for helping to reduce my confusement.
> Nick England K4NYW
> www.navy-radio.com <http://www.navy-radio.com>
>
>
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