[GreenKeys] Model 28D typing unit question

[jhhaynes at earthlink.net]

On Sat, 19 Jan 2008, Nick England wrote:

> Anyway - 28D mystery keyboard driving gear looks like163503
>                28A standard keyboard driving gear is 150441 (which matches
> all the manuals I have)

I'm looking at 573-115-800TC Issue 3 May 1969.  It says
150441 is for 7.42 and 11.0 unit code
163503 is for 7.00 unit code, 50/75 Baud
178764 is for 7.00, 7.50 unit code

On the keyboard the driving gear is part of the same piece that has the
clutch.  The normal one i(Mark II) seems to be 151154  There is a 163519 
that is part of a mod kit (320236) to modify keyboard with distributor 
from 7.42 code to 7.00 unit code operating at 8.05 [sic] Baud.  Then on 
another page for Signal Generator Shaft Mechanism Mark III it says
154032 for 7.42 unit code, 163519 for 7.00 unit code, and 178787 for
7.50 unit code.

What I can't explain is why any code other than 7.42 would be used on
a Bell System unit.

I didn't really get the picture where you are talking about contacts
on the spacing drum associated with tab stops.  However it was normal
in an ASR or a printer associated with tape sending to have contacts
on the tab mechanism in the printer.  This was to open the circuit to
the feed magnet on the tape reader so as to stop the tape reader long
enough for the tab operation to complete before reading the next
character from tape.  What a kluge!