In the late 1940s Western Union introduced a small desk top sized
facsimile machine which was a major innovation for its day. Before
that, fax machines were huge.
The goal was to replace telegraph messengers who were becoming quite
expensive and provide a faster service -- desk to desk. Also, these
machines were cheaper than a Teletype. The Western Union Tech Review
(on this website) has articles on the details of transmission. A lot
of experimentation went into all facets of transmission issues to
maximize clarity and minimize errors. I believe the document size was
rather small, about 4x6 inches.
I am not sure if the fax signal was analog, varying as the reading eye
moved across the line, or digital, with the line divided into tiny
segments. A digital signal could be carried on low speed telegraph
lines and converted to paper tape but would be pretty slow. I also
don't know how the messages were routed -- did the fax print out at a WU
switching center, read by a human, and re-transmitted to the
destination? If so, was the fax resent, which would mean a very
coarse final result, or was the image stored on paper tape (as other
telegraph messages were) and resent that way?
(Western Union also handled larger size facsimile transmission, such
as weather maps for the US weather bureau and private line
transmissions, but that is separate*).
Anyway, in 1962 there were 38,000 Desk Fax terminals in operation.
Obviously it was popular.
As voice-telephone line fax machines and cheaper long distance rates
came out the need for Desk Fax declined. At some point Western Union
had to pull the plug on the service. I tried searching for a
terminate date, but couldn't find any. Would anyone know when WU
discontinued this particular service and how many terminals remained
in use? Would anyone know any other details about the service?
*In 1962 W.U. had a "Public Wirefax" service, which cost $4.00 for a
coast-to-coast 8x11" page transmission, additional pages at 65 cents.
