STARS:Telephone Transmission
From GHN
Author: Sheldon Hochheiser
Citation
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.
Timeline
| 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. |
Essay
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References of Historical Significance
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