AT&T Communications - East, Inc. was a holding company for the 23 subsidiaries that provide interexchange carrier and long distance telephone services owned by AT&T. The American Telephone & Telegraph Long Lines wire, cable, and microwave radio relay network provided long-distance transport services to AT&T and its customers from the late 1940s to the early 1980s. Formal opening of the coast-to-coast connection was on August 17, 1951. A sophisticated achievement, Long Lines provided computerized reconfiguration of microwave circuits coast-to-coast via AT&T's network... control center in New York City. By the 1970s, Long Lines carried 95% of all long-haul television traffic and 70% of intercity telephone calls in the United States. Before utilizing microwave relay and coaxial cables, AT&T used heavy-duty carrier grade open-wire lines for long distance service. In 1911, the system connected New York to Denver. The introduction of vacuum tube amplifiers in 1914 allowed such connections to reach across North America. In the 1930s the company experimented with long-distance coaxial cable. The first long-distance L-carrier coaxial link in 1936 connected Philadelphia and New York.
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