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Abstract
Many of the highlights in the history of telecommunications are discussed. Sounds were transmitted electronically via several meters of extended wire as early as 1677, but it was not until 1872, when the telegraph companies began to search for a way to send multiple telegraph messages over the same line, that telephony got its true start. By 1887, nearly 146,000 miles of wire connected more than 150,000 telephone subscribers to 743 main and 44 branch exchanges in the US. Wired broadcasting experiments took place in 1881, and the technology was deployed commercially in the 1890s. Some European countries used "wired" radios to broadcast music, news, stock market reports, and theater. In 1917, an electrical band-pass invention made it possible to multiplex several signals over a single telephone circuit using a radio frequency carrier for the number of voice channels needed. The first radio frequency carrier system went on line in 1918.