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