Invention & History of Telephone (Phone)

Invention of Telephone:-

Credit for the invention of the electric telephone is frequently disputed, and new controversies over the issue have arisen from time-to-time. Charles Bourseul, Antonio Meucci, Johann Philipp Reis, Alexander Graham Bell, and Elisha Gray, amongst others, have all been credited with the telephone's invention. The early history of the telephone became and still remains a confusing morass of claims and counterclaims, which were not clarified by the huge mass of lawsuits to resolve the patent claims of many individuals and commercial competitors. The Bell and Edison patents, however, were commercially decisive, because they dominated telephone technology and were upheld by court decisions. Alexander Graham Bell has most often been credited as the inventor of the first practical telephone. Additionally, the Italian-American inventor and businessman Antonio Meucci has been recognized by the U.S. House of Representatives for his contributory work on the telephone.  In Germany, Johann Philipp Reis is seen as a leading telephone pioneer who stopped only just short of a successful device. However, the modern telephone is the result of work done by many people, all worthy of recognition of their contributions to the field. Bell was, however, the first to patent the telephone, an "apparatus for transmitting vocal or other sounds telegraphically".

Early telephone developments:-

The following is a brief summary of the history of the development of the telephone:
• 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".
• 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, California.