[GreenKeys] Western Union tape transmitter 22-A by J H Bunnell

[Duncan Brown]

Jag,

 From around 1910 on, it was customary in high volume communication 
centers (both commercial & military) to first punch messages into paper 
tape using the 5-bit Baudot code. It would then be read by a tape reader 
and sent out onto the signal line at the maximum system speed.  A loop 
of tape between the tape-punching machine (perforator) and the tape 
reader acted as a buffer to accept variations in the typist's speed. The 
tape could be resent to multiple destinations and was also kept as a 
copy of what had been sent.  This was the standard for all high-volume 
message traffic in both commercial and military communications up until 
the 1970s.

The picture enclosed shows a Western Union Operating table of about 
1920. The perforator is on the right, with the tape reader to its left 
(look closely and you can see the loop of tape between the two).  The 
tape reader read the 5 bits in parallel, then they were sent to a 
parallel to serial converter (distributor) where they were (time 
division) multiplexed with up to 3 other circuits and sent out 
(serially) on the line. A page printer is on the left.

I am familiar with Bunnell as a manufacturer of telegraph equipment, but 
did not know that they made "printing telegraph" equipment. Please send 
a picture of your unit (you can enclose a file of up to 1 MB on this 
email list).

Western Union bought equipment from a lot of different manufacturers and 
put their own name & model number on them.  But they often used the same 
model number for different types of equipment.  for Example, you have a 
WU Model 22-A tape reader, but there was also a WU Model 22A tape 
printer, so it can be confusing.

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 31-Jan-15 17:47, jag wrote:
>  Hi folks.
>
> This is my first ever post and I was wondering if you could help me... 
> I have acquired a tape transmitter but know very little about it... 
> Any information would be helpful. Its made by J H Bunnell for the 
> Western Union company. The model number is 22-A. I believe its dated 
> around 1920 - 1930. The serial number on the item is 80.
> What could it have used for? Were they widely used in the UK? Armed 
> forces usage? I purchased the item in north Wales as it intrigued me 
> as to its history and use.
>
> Thanks in advance.
>
> Jag
>



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