T1: A Survival Guide

1951-1970:The Birth of T-carrier

It may not have been obvious at the time, but the telephone network was on the cusp of a fundamental change driven by several factors. Early long-distance connections, especially those across an ocean, were full of static and could fade quite abruptly. Development of appropriate cabling would eliminate the problems caused by the use of radio waves, but noise and distortion of the analog signal across such great distances posed a large problem. Postwar prosperity in the U.S. dramatically increased the demand for telephone service, bringing with it millions of new telephone users and requiring ever more operators to connect calls. Better means of providing service had to be found. Fortunately, two new technologies came to the rescue.

The Transistor and Computerization

The transistor, invented in 1947 at Bell Labs, made it possible to construct sophisticated electronics. Today’s semiconductor and computer industries owe their existences to the transistor. Transistors also made AT&T’s “Electronic Switching System” possible. In the early 1960s, AT&T built and field-tested specialized, programmable devices for controlling the telephone network. These devices, of course, were computers, but the terms of the 1956 consent decree prohibited AT&T from manufacturing computers. AT&T followed the time-honored tradition of redefining terms in the argument. AT&T deployed the first such device, the No. 1 ESS, in New Jersey in 1962 following a field trial. ...