An experimental switching system using new electronic techniques [telecom]

Dec 13, 2011 2 Replies
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An experimental switching system using new electronic techniques [telecom] open original image

I came across a fascinating paper by A. E. Noel, Jr. , in the Bell System Technical Journal: it gives an amazing insight into the coming of the "digital" age in telephone switching, and into many "what if" technologies that never made it off the drawing board.



It's titled "An Experimental Switching System Using New Electronic Techniques"



This is the first of a series of articles describing an experimental electronic telephone switching system employing a number of new techniques. These include use of a stored program, a network employing gas tube crosspoints, time-division common control, and large-capacity barrier grid tube and photographic storage systems.



The article is at

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J

Make that A. (for Amos) E. Joel.

This sounds like the early design of the Morris (Ill.) ESSl

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The Morris experiment could not handle traditional ringing current (about 90V 25 Hz) through the crosspoints, so they used low powered tone ringered in the telephone sets. The sets also had some amplification, and were given 20 pps dials instead of 10 pps. The

1925-1975 Bell Labs history has a whole chapter on this. Various technologies were considered. Later ESS used a metallic connection "remreed" which did allow continued use of existing telephone sets.

The Bell Labs history and issues of the "Bell Laboratories Record" magazine tend to present the history in somewhat more layman's terms. The BSTJ tends to go in heavy for the math equations. I hope someday the "Record" will go on-line. A few issues have been put up privately.

Some large PBX switchboards also had fast 20 pps dials. A friend of mine modified his home phone and it worked (served by either panel or No. 1 xbar).

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