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Wednesday, 29 June 2011

Early telephone developments

Early telephone developments

The following is a brief summary of the history of the development of the telephone:
A French Gower telephone of 1912 at the Musée des Arts et Métiers in Paris
  • 1667: Robert Hooke invented a string telephone that conveyed sounds over an extended wire by mechanical vibrations.
  • 1844: Innocenzo Manzetti first mooted the idea of a “speaking telegraph” (telephone).
  • 1854: Charles Bourseul writes a memorandum on the principles of the telephone.(See the article : "Transmission électrique de la parole", L'Illustration, Paris, 26 August 1854).
  • 1854: Antonio Meucci demonstrates an electric voice-operated device in New York; it is not clear what kind of device he demonstrated.
  • 1861: Philipp Reis constructs the first speech-transmitting telephone
  • December 28, 1871: Antonio Meucci files a patent caveat No. 3353 at the U.S. Patent Office for a device he named "Sound Telegraph".[2]
  • 1872: Elisha Gray establishes Western Electric Manufacturing Company.
  • July 1, 1875: Bell uses a bi-directional "gallows" telephone that was able to transmit "voicelike sounds", but not clear speech. Both the transmitter and the receiver were identical membrane electromagnet instruments.
  • 1875: Thomas Edison experiments with acoustic telegraphy and in November builds an electro-dynamic receiver, but does not exploit it.
  • 1875: Hungarian Tivadar Puskas (the inventor of telephone exchange) arrived in the USA.
  • April 6, 1875: Bell's U.S. Patent 161,739 "Transmitters and Receivers for Electric Telegraphs" is granted. This uses multiple vibrating steel reeds in make-break circuits, and the concept of multiplexed frequencies.
  • January 20, 1876: Bell signs and notarizes his patent application for the telephone.
  • February 11, 1876: Elisha Gray designs a liquid transmitter for use with a telephone, but does not build one.
  • March 7, 1876: Bell's U.S. patent No. 174,465 for the telephone is granted.
  • March 10, 1876: Bell transmits the sentence: "Mr. Watson, come here! I want to see you!" using a liquid transmitter and an electromagnetic receiver.
  • January 30, 1877: Bell's U.S. patent No. 186,787 is granted for an electromagnetic telephone using permanent magnets, iron diaphragms, and a call bell.
  • April 27, 1877: Edison files for a patent on a carbon (graphite) transmitter. Patent No. 474,230 was granted on May 3, 1892, after a 15-year delay because of litigation. Edison was granted patent No. 222,390 for a carbon granules transmitter in 1879.
  • 1877: First long-distance telephone line
  • 1915: First U.S. coast-to-coast long-distance telephone call, ceremoniously inaugurated by A.G. Bell in New York City and his former assistant Thomas Augustus Watson in San Francisco, Californi

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