[GreenKeys] Distributor of Sorts

[Duncan Brown]

It is a "data concentrator" from c1920.  It looks like one distributor 
could take eight, 5-bit, synchronous, TTY channels and multiplex them 
onto one wire of telegraph cable. (One distributor may be for transmit 
and the other for receive.) This system was used previous to the 
Start-Stop TTYs that we use, but the synchronous 5-bit TTY system was 
continued to be used up until about 1940.

This is an improved model of what Emile Baudot invented 40 years earlier.

When Emile Baudot invented the 5-bit printing telegraph in 1883, it was 
not much faster than the standard telegraph, so he also invented 
Time-Division Multiplex for faster transmission. His original system 
multiplexed four TTY channels. If there are four operators, each typing 
their own message at 50wpm, the system throughput would be 200wpm.

Baudot's keyboard only had five keys - the operator had to know the 
Baudot Code. The five keys connected to individual contacts on the 
distributor (time-division multiplexer) which did a parallel to serial 
conversion. At the other end of the line, a similar distributor 
(time-division demultiplexer), did a serial to parallel conversion with 
five outputs for each channel. Tghe five bits for each channel were sent 
to a printer with five selector magnets (a sixth solenoid was energized 
to print the character when the data had been received). Printers that 
operated in this synchronous/multiplex system where the Western Union 
Models 20, 21, & 22 tape printers (made by Kleinschmidt Electric and 
Morkrum) and the Morkrum Model 12 page printer.

Here is a simplified drawing of Baudot's Multiplex system showing the 
connections for just one channel:



have fun,

Duncan
K2OEQ



On 07-Jun-18 10:08, Doug Hensley wrote:
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> 123175604832
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