The Telephone Switchboard
Alexander Graham Bell
Alexander Graham Bell, a Scotsman who came to the United States in 1871, invented the telephone. Bell was a teacher of the deaf in Boston. At night, he experimented with a harmonic telegraph, a device for sending several telegraph messages at once over one wire. Bell developed the idea of the telephone in 1874, but he continued his experiments with the harmonic telegraph.
On June 2, 1875, one of the metal reeds of the harmonic telegraph stuck. Bell's assistant, Thomas A. Watson, plucked the reed to loosen it. Bell, who was in another room, heard the sound in his receiver. He realized that the vibrations of the reed had caused variations of electric current. In turn, the electric current had reproduced the same variations in the receiver he was using.
On March 10, 1876, Bell finally succeeded in speaking words over a telephone. He was about to test a new transmitter. In another room, Watson waited for the test message. Suddenly, Bell spilled some acid from a battery on his clothes. He cried out: "Mr. Watson, come here. I want you!" Watson heard every word clearly and rushed into the room.
In June 1876, Bell exhibited his telephone at the Centennial Exposition in Philadelphia. Scientists praised his work. But the public showed little interest until early in 1877, when Bell gave many demonstrations.
In August 1876, Bell received the first one-way long-distance call. This call came over an 8-mile telegraph line between Brantford, Ontario, and Paris, Ontario. In October 1876, Bell and Watson held the first two-way long-distance telephone conversation. They spoke between Boston and Cambridgeport, a part of Cambridge, Massachusetts, a distance of 2 miles. In 1877, Charles Williams, an electrical workshop owner, installed the first line intended exclusively for telephone use. It extended 3 miles between Williams's home in Somerville, Massachusetts, and his shop in Boston.
The first telephones used no switchboards. A pair of iron wires connected each pair of phones. As more telephones came into use, each was connected to all the other phones. More than 1,000 connections were required to link only 50 telephones. Switchboards solved this problem by bringing together the wires from all telephones in an area. The first switchboard began operating in 1877 in Boston.
Almon B. Strowger, an American inventor, patented an automatic switching system in 1891. The first commercial switchboard based on his patent opened in LaPorte, Indiana, in 1892. The caller pressed buttons to get the number, then turned a crank to ring the phone. Also in 1892, phone service began between New York City and Chicago.
In 1896, the first dial telephones went into operation in Milwaukee. Transcontinental phone service began between New York City and San Francisco in 1915. Transatlantic radiotelephone service between New York City and London began in 1927. The first long-distance coaxial cable linked New York City and Philadelphia in 1936.
Undersea telephone cables between North America and Europe began operating in 1956. A cable between the U.S. mainland and Hawaii began operating in 1957. A cable from Japan was joined to this cable in 1964, connecting Japan to the U.S. mainland. The first commercial communications satellite, Early Bird, was launched in 1965.
SOURCE: IBM 1999 WORLD BOOK
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