[GreenKeys] Kleinschmidt, Morkrum, M-K, M14-TP, and other early stuff

[Charles Ring W3NU]

jhhaynes at earthlink.net wrote:
>
> On Wed, 5 Apr 2006, Charles Ring W3NU wrote:
>
>> Why would anyone want a new Model 12 as late as 1943? Parts and 
>> support sure, but new machines? The 15 had to be better, cheaper and 
>> more reliable. Were 15's not entirely compatible with systems 
>> designed around 12's?
>>
> Model 12 was parallel input, and therefore was used in some time-division
> multiplex systems that were probably still in use at that late date.
>
>

Is there a really good explanation online of how the model 12 worked? 
Decades ago I knew more about it than i do now but not really a lot. 
Multiple selector magnets and a receiving distributor are things I do 
remember. I know that many ham radio operators used them (serial) into 
the 60's. I also know that the Chicago police used them into the 50's 
but i don't know why or what kind of network. I also know that they 
often ran at 40wpm but they must have been capable of 60 since that is 
the only speed hams were allowed to use back then. I also assume that 
40wpm gears were available for 15's for backward compatibility, or maybe 
some of the parts of the 15 didn't work well so slowly?? The only model 
12 i ever saw myself was filthy and in pieces at a hamfest flea market 
decades ago.

73 de W3NU