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STARS:Telephone Transmission

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Author: Sheldon Hochheiser


Transmission is the means by which telephone conversations get from one place to another. Transmission media have evolved over the years in ways that improved quality, removed distance limitations, and increased capacity, in line with the evolution of the predominant medium through multiple transformations. These began with iron wire and have culminated in today’s fiber optic cable. In doing so, telephone service, has become less expensive and more widely available, thus playing an increasingly important role in bringing people together: across town, across continents, and around the world. This article does not cover cellular telephony, which merits its own article.


1878 First telephone exchange opens in New Haven, Connecticut.
1881 First Commercial Long Distance Line opens, Boston-Providence.
1881 Alexander Graham Bell patents the metallic, or two-wire, circuit.
1884 Hard-drawn copper wire begins to replace iron wires.
1891 Twisted pairs incorporated into telephone lines by John J. Carty.
1899 Loading Coil theory developed independently by Michael Pupin and George Campbell.
1915 First U.S. transcontinental telephone line, using vacuum tube amplifiers developed by Harold Arnold.
1918 First installation of carrier circuits, based on work by George Campbell.
1927 Transatlantic telephone service opens via radiotelephony.
1929 Broadband coaxial cable invented by Lloyd Espenschied and Herman Affel.
1941 First U.S. commercial coaxial cable installation, Minneapolis, Minnesota to Stevens Point, Wisconsin.
1947 First microwave relay system in the telephone network, New York to Boston.
1956 First transatlantic telephone cable opens, Newfoundland-Scotland.
1962 T-1, first digital transmission system installed.
1965 Charles Kao conceives of using light sent over glass fibers as a transmission medium.
1977 First local, commercial, fiber-optic transmission system, Long Beach, California.
1982 First long-distance, fiber-optic transmission system, New York to Washington, D.C.
1988 First transatlantic fiber-optic cable opens, New Jersey to England and France.



References of Historical Significance

References for Further Reading

About the Author(s)