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Innocenzo Manzetti first mooted the idea of a “speaking telegraph” or telephone. Use of the 'speaking telegraph' and 'sound telegraph'
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Charles Bourseul published an article in the magazine L'Illustration (Paris): "Transmission électrique de la parole" (electric transmission of speech), describing a 'make-and-break' type telephone transmitter later created by Johann Reis.
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Johann Philipp Reis (1834–1874) publicly demonstrated the Reis telephone before the Physical Society of Frankfurt
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La Feuille d'Aoste reported “It is rumored that English technicians to whom Mr. Manzetti illustrated his method for transmitting spoken words on the telegraph wire intend to apply said invention in England on several private telegraph lines". However telephones would not be demonstrated there until 1876, with a set of telephones from Bell.
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Antonio Meucci files patent caveat No. 3335 in the U.S. Patent Office titled "Sound Telegraph", describing communication of voice between two people by wire. A 'patent caveat' was not an invention patent award, but only an unverified notice filed by an individual that he or she intends to file a regular patent application in the future.
1874 — Meucci, after having renewed the caveat for two years does not renew it again, and the caveat lapses -
Meucci, after having renewed the caveat for two years does not renew it again, and the caveat lapses.
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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.
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Gray invents a liquid transmitter for use with a telephone but does not build one.
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Elisha Gray files a patent caveat for transmitting the human voice through a telegraphic circuit.
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Alexander Bell applies for the patent "Improvements in Telegraphy", for electromagnetic telephones using what is now called amplitude modulation (oscillating current and voltage) but which he referred to as "undulating current".
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Gray is notified by the U.S. Patent Office of an interference between his caveat and Bell's patent application. Gray decides to abandon his caveat.
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Bell's U.S. patent 174,465 "Improvement in Telegraphy" is granted, covering "the method of, and apparatus for, transmitting vocal or other sounds telegraphically … by causing electrical undulations, similar in form to the vibrations of the air accompanying the said vocal or other sound.
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the first successful telephone transmission of clear speech using a liquid transmitter when Bell spoke into his device, “Mr. Watson, come here, I want to see you.” and Watson heard each word distinctly
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Edison files for a patent on a carbon (graphite) transmitter. The patent 474,230 was granted 3 May 1892, after a 15 year delay because of litigation. Edison was granted patent 222,390 for a carbon granules transmitter in 1879.
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Bell's U.S. patent 186,787 is granted for an electromagnetic telephone using permanent magnets, iron diaphragms, and a call bell.
