[GreenKeys] WU 1-A documentation

[Duncan Brown]

Nick,

Here is a WU spec on the 1-A tape reader.  It was designed for use in 
the WU synchronous, four-channel multiplex system.

Note that it is set up for differential keying, ie positive voltage for 
mark and negative voltage for space.  This was required for long 
telegraph lines (especially undersea cables) to overcome the inductance 
of the long line, But it was later dropped for shorter lines (especially 
when connected to a modem and/or radio) and the space connection was 
left open.

The M14 Transmitter-Distributor used essentially the same (parallel) 
tape reader and then needed the big "distributor" to do the 
parallel-to-serial conversion.

I have some more info on the WU 1A tape reader, but will have to get it 
scanned.

We have a couple of similar units at the AWA Museum, but none that are 
in that good a shape!

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 25-Nov-16 18:01, Nick wrote:
> If you have any documentation on my Western Union 1-A Multiplex 
> Transmitter, please let me know. Hope the 5 pictures went through.
> Nick N0NCQ
>



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