81 lines
4.4 KiB
Plaintext
81 lines
4.4 KiB
Plaintext
The History of ESS Courtesy of the Jolly Roger
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Of all the new 1960s wonders of telephone technology -
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satellites, ultra modern Traffic Service Positions (TSPS) for
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operators, the picturephone, and so on - the one that gave Bell
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Labs the most trouble, and unexpectedly became the greatest
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development effort in Bell System's history, was the perfection
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of an electronic switching system, or ESS.
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It may be recalled that such a system was the specific end in
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view when the project that had culminated in the invention of the
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transistor had been launched back in the 1930s. After successful
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accomplishment of that planned miracle in 1947-48, further delays
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were brought about by financial stringency and the need for
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further development of the transistor itself. In the early 1950s,
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a Labs team began serious work on electronic switching. As early
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as 1955, Western Electric became involved when five engineers
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from the Hawthorne works were assigned to collaborate with the
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Labs on the project. The president of AT&T in 1956, wrote
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confidently, "At Bell Labs, development of the new electronic
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switching system is going full speed ahead. We are sure this will
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lead to many improvements in service and also to greater
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efficiency. The first service trial will start in Morris, Ill.,
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in 1959." Shortly thereafter, Kappel said that the cost of the
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whole project would probably be $45 million.
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But it gradually became apparent that the developement of a
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commercially usable electronic switching system - in effect, a
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computerized telephone exchange - presented vastly greater
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technical problems than had been anticipated, and that,
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accordingly, Bell Labs had vastly underestimated both the time
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and the investment needed to do the job. The year 1959 passed
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without the promised first trial at Morris, Illinois; it was
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finally made in November 1960, and quickly showed how much more
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work remained to be done. As time dragged on and costs mounted,
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there was a concern at AT&T and something approaching panic at
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Bell Labs. But the project had to go forward; by this time the
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investment was too great to be sacrificed, and in any case,
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forward projections of increased demand for telephone service
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indicated that within a phew years a time would come when,
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without the quantum leap in speed and flexibility that electronic
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switching would provide, the national network would be unable to
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meet the demand. In November 1963, an all-electronic switching
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system went into use at the Brown Engineering Company at Cocoa
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Beach, Florida. But this was a small installation, essentially
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another test installation, serving only a single company.
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Kappel's tone on the subject in the 1964 annual report was, for
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him, an almost apologetic: "Electronic switching equipment must
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be manufactured in volume to unprecedented standards of
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reliability.... To turn out the equipment economically and with
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good speed, mass production methods must be developed; but, at
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the same time, there can be no loss of precision..." Another year
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and millions of dollars later, on May 30, 1965, the first
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commercial electric centeral office was put into service at
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Succasunna, New Jersey.
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Even at Succasunna, only 200 of the town's 4,300 subscribers
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initially had the benefit of electronic switching's added speed
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and additional services, such as provision for three party
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conversations and automatic transfer of incoming calls. But after
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that, ESS was on its way. In January 1966, the second commercial
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installation, this one serving 2,900 telephones, went into
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service in Chase, Maryland. By the end of 1967 there were
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additional ESS offices in California, Connecticut, Minnesota,
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Georgia, New York, Florida, and Pennsylvania; by the end of 1970
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there were 120 offices serving 1.8 million customers; and by 1974
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there were 475 offices serving 5.6 million customers.
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The difference between conventional switching and electronic
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switching is the difference between "hardware" and "software"; in
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the former case, maintenence is done on the spot, with
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screwdriver and pliers, while in the case of electronic
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switching, it can be done remotely, by computer, from a centeral
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point, making it possible to have only one or two technicians on
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duty at a time at each switching center. The development program,
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when the final figures were added up, was found to have required
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a staggering four thousand man-years of work at Bell Labs and to
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have cost not $45 million but $500 million!
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