[GreenKeys] Prehistory of "the net"

[jhhaynes at earthlink.net]

First time I sent this I got blocked by spamcop.  I'm on a dialup, hence
a floating IP adress, and apparently somebody used this address previously
to send spam.  So this is second attempt


>From the late 1930s to the early 1960s large companies and government
agencies had automatic store-and-forward message switching systems.
Plus there were a lot of torn-tape store and forward systems, and some
where the tape was not torn but the operator read the message address
and used plug and jack or pushbuttons to route the message to the
correct outgoing line.

Maybe the earliest automatic system was Bell 81C1, believe it was 
built for Republic Steel and featured fully automatic switching with
a single switching center.  The later 81D1 allowed for multiple
switching center, and was eventually upgraded to 100WPM.  Western
Union had its Plan 21-A for public telegrams.  In Plan 21-A the
final routing was almost always done by a person at a pushbutton
console, because public telegrams are sent to a person at a street
address and that's too complicated for an automatic system to route.
W.U. also had the Plan 51 pushbutton system for its private line
customers.  

Circa 1960 each of the U.S. military services had its own switching
sytem, and each done differently.  The Air Force had Western Union
Plan 55.  I believe it was leased but used military personnel for
maintenance.  The Army had a military-nomenclatured system AN/FGC-30
built by Automatic Electric and Kleinschmidt.  And the Navy had its
82B1 system leased from Bell.  The FAA had a weather switching system
ADIS made by Teletype, and a little later a message switching system
called BDIS.  (ADIS was an acronym for Automatic Data Interchange
System.  BDIS was sort of a pun, as ADIS was used in Service A and
BDIS was used in Service B.)  Most of the airlines had message switching
systems from W.U. or Bell.  Delta Airlines and then United had a
line-switched system provided by Bell, with a facility to interchange
traffic with the message-switching systems of other airlines.

AUTODIN started out as a replacement for the Air Force COMLOGNET
(Combat Logistics Network) which was a network of IBM punched card
transceivers operated in the manner of a torn-tape system.  Its name
got changed, first to AF DATACOM and then to AUTODIN and then
DCS AUTODIN.  Mission creep: what started out for switching punched
card data was adapted to Teletype messages and magnetic tape; and
the system was taken over by the Defense Communications Agency and
made the replacement for the previous switching systems of all the
services.  AUTODIN used a combination of store-and-forward and
circuit switching, the latter to permit real-time two-way exchanges
and also to aid in handing magnetic tape, which otherwise would require
a lot of storage and incur a long delay with storing and forwarding.
AUTODIN was based on computer technology rather than paper tape and
relays.  The prime contractor was Western Union and the computers
were made by RCA - initially discrete transistor models.

In the same time frame computer technology began to replace punched
tape in the other store-and-forward systems.  Several companies built
computers especially for this market.  IBM had its 7740 Programmed
Transmission Control.  G.E. had the Datanet-30.  Collins Radio had
its C-8400 system.  Several Univac computers were used for the purpose.
ITT had a machine for switching, and no doubt others.   FAA had
engaged Teletype to design a third system, to be called CODIS for
Services C and O, and then cancelled the project in favor of a
computer.

The switching computer business had a fairly short life, because the
business world moved quickly into online computer systems which
could handle messages as a byproduct.  For example, American Airlines
and IBM produced the Sabre reservations system.  Some of the switching
computers, especially the Datanet-30, found new uses as communication
front ends for computer systems.  

Bell Laboratories modified its #1 Electronic Switching System to do
message switching, calling it the #1ESS-ADF.  Apparently they had in
mind that one switching machine could perform store and forward
switching for several private line customers.  But the market for
pure message switching had already gone by.  My understanding is
that #1ESS-ADF was used for an internal Bell System message system
and was also used to aid in switching TWX traffic, but was never
used as a message switcher for any customers.
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jhhaynes at earthlink dot net