[GreenKeys] 7.42 vs. 7.0 machines/

[W9DDD]

OK, I kind of had the impression that 7.0 28 was military since the 
keyboard had RFI filtering and a Synchronous Pulsed Transmission 
solenoid and aux contact (crypto machine?).  I suppose business machine 
interface as well?

The printer turned out to be weird (to me) also.  I've seen loaded stunt 
boxes with auxiliary connectors before that sit next to the regular 
connector.  This one has just a 35 pin connector and the selector 
magnets are wired to it along with the plethora of stunt box stuff.  I 
actually found the WD for this one. Selector magnets wired in parallel 
at the printer instead of on the A strip.

Since I found information on both of these in NAVSHIPS instead of BSPs, 
I leapt to the assumption they were military.  The cabinet also was only 
found in the NAVSIPS.

I guess checking the keyboard driving gear on the printer main shaft 
will tell me the full story.

I am able figure out some of the features from the number plates. 
Things like type box arrangements and stunt box arrangements are listed, 
  but it takes some detective work to figure out what those parts in 
those slots actually do.

The WU machine has a different ESU.  My guess after reading what WU WDs 
are available is that it might be a 9100 wiring cabinet?

John, W9DDD

On 12/2/2018 2:21 PM, Jim Haynes wrote:
> In a recent posting I told the origin of 7.42, it being a design sort-of
> flaw in a Western Electric printing telegraph.  Morkrum could do 7.00 code
> from the beginning, but the Bell System required 7.42 for interoperability
> with the earlier W.E. machines.
> 
> Western Union always liked 7.00 code and bought most of their machines
> that way.  Bell System and the U.S. military and other non-W.U. customers
> got 7.42 from Teletype.
> 
> Teletype printers can receive 7.00 code just fine, at full speed as it
> comes from a tape transmitter.  That's because in Teletype design the
> receiving shaft completes its rotation in time to latch up the clutch
> even if the stop pulse is only one unit long.  With 7.42 it just rests
> a little longer.  I believe this is true even for the Model 32, but
> don't hold me to that.  I don't know that much about the 32/33 line.
> 
> A 7.00 keyboard requires a different cam and gearing from the 7.42
> because the keyboard shaft has to turn faster in 7.00.
> 
>