[GreenKeys] M12

[Duncan Brown]

It was good to see Jack at the AWA Museum yesterday and talk about TTYs  
(& mobile telephones).

Enclosed is a better picture of the Museum's M12.

The M12 was the first commercially successful page printer with almost 
12,000 units produced from 1922-1943. It was designed around the 
typebars & operating mechanism of an L. C. Smith typewriter, with the 
platen of a Woodstock typewriter. There are only about a half dozen M12s 
know to still be in existence today.

When I first saw pictures of the M12, I wondered why it had two motors. 
I now believe that the printer, which has 5 selector magnets, must have 
been originally designed as a Receive Only printer, to be used in the 
multiplex services that were popular around 1920. These were generally 
one-way services, used by WU & news services such as Associated Press. 
(See second picture of a row of M12 ROs in a newsroom.)

After Howard Krum invented start-stop transmissions, two-way 
communications became practical. A plug-in "Direct to Line" keyboard was 
added to the M12 printer, with its own motor. You will recognize the 
"goose neck"  cam operated keyboard contacts that were later used on the 
M14 & M15 keyboards. The second set of goose neck contacts is a serial 
to parallel converter for the printer, to enable it to operate on a 
serial line.

If you have a copy of Kretzman's "The New RTTY Handbook", there is a 
section in there on the M12.

Have fun,

Duncan Brown, K2OEQ
USASA  31J30

Antique Wireless Association Museum Asst. Curator, Commercial Equipment
(also Chief TTY operator & repairman)
http://www.antiquewireless.org/



On 20-Jun-18 17:10, Jack wrote:
> ZCZC
>
> On the way to see my sister in Buffalo, NY, my wife and stopped at the
> Antique Wireless Museum
> in Bloomfield, NY (south of Rochester) on Tuesday.  I was able to visit some
> of my old "friends" that were
> donated to the Museum over the years.
>
> I took a picture of the Model 12 because it's the first one I have seen in
> the flesh. It is in
> very nice condition. (The Model 15 next to it was one of my donations.)
>
> Duncan, K2OEQ, a Greenkeys member, gave me the special tour. We talked for
> hours
> until we were both hoarse! Duncan has a very impressive TTY collection on
> display,
> with more to come.
>
> I strongly recommend a visit. I'll have to go back because I only saw maybe
> 25% of
> the stuff they have on display.
>
> 73,
> Jack K2TTY
>



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