[GreenKeys] Model 15 Keyboard

[steve bennett]

Jim,

Yes you are correct about the cams.
I did a search in the document to see if the term "Bell System Standard" appeared anywhere else
and the other place it showed up was on the cam. They list two part numbers for the cam.
One for 7.00 and one for 7.42.

-Steve     On Thursday, February 27, 2025 at 10:51:18 PM EST, Jim Cooper <jim.w2jc at gmail.com> wrote:  
 
 On 28 Feb 2025 at 2:48, steve bennett via GreenKeys 
wrote:

> Just counted the keyboard gear teeth
> on my M15. Machine was a RO for
> Associated Press so it didn't even
> have a keyboard originally but for
> what it's worth the keyboard gear on
> the main shaft is 21T which is what
> the manual calls Bell System
> Standard. That is in agreement with
> the gear on the keyboard John sent
> me. Also a bell system standard.
> Whatever that means. 

You are lucky that you have the gears for 
the "Bell system standard" ... 

as you typed earlier but did not realise it, 
there are two TYPES of baudot signals ... 

7.00 and 7.42 ...  first is common on WU gear; 
second is common for everyone else !!  

has to do with the length of the STOP pulse... 
7.42 allows time for the rotating shafts to 
complete and stop before the next start pulse. 

7.00 runs with the same length stop pulse 
as are all the other bits of the code, thus no 
'catchup' time ...  WU thought they would be 
cute and 'faster' by cutting down the stop length. 

The kbd gears have to account for that timing, 
as do the cams, etc. 

w2jc 


  
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