page_title: History of the telephone
section_title: Early telephone developments
hierarchical_section_title: History of the telephone / Early telephone developments
caption_attribution_description: Italiano: È costituito da un cilindro e un padiglione circolare (cavità acustica) entrambi realizzati in legno. All'interno del cilindro è inserito un magnete rettilineo. Sul polo di questo magnete è inserito un elettromagnete cilindrico i cui capi terminano a due serrafili posti sul retro del padiglione. Davanti all'elettromagnete, in corrispondenza del padiglione, è fissata una membrana in ferro dolce. Funzione Questo telefono di Meucci è servito alle prime sperimentazioni dell'inventore italiano sulla trasmissione della voce. Modalità d'uso Questo telefono funzionava in coppia con un suo analogo. Due telefoni di Meucci venivano messi in collegamento e alternativamente funzionavano da trasmettitore e da ricevitore Il telefono di Meucci, utilizzato come trasmettitore, convertiva le vibrazioni meccaniche della membrana, colpita dalle vibrazioni sonore prodotte dalla voce, in variazioni elettriche nell'elettromagnete. Ad ogni suono corrispondeva una precisa ed univoca variazione elettrica (corrente modulata) Tramite il collegamento questo segnale elettrico arrivava ai serrafili dell'altro telefono (ricevitore). Qui la corrente modulata, circolando nell'elettromagnete, creava un campo magnetico variabile. La membrana, di ferro dolce, veniva così messa in oscillazione. Data la corrispondenza tra vibrazioni meccaniche, acustiche e corrente elettrica, le vibrazioni della membrana restituivano esattamente i suoni in ingresso nel trasmettitore. Notizie storico-critiche Questa replica del telefono di Meucci, modello del 1857, insieme all'altra del modello del 1867, vennero fatti costruire a cura del CNR Consiglio Nazionale delle Ricerche (sotto la Presidenza Guglielmo Marconi), dalle Officine Galileo di Firenze per inviarli all'Esposizione Internazionale "A Century of Progress" tenutasi a Chicago nel 1933.
context_page_description: This history of the telephone chronicles the development of the electrical telephone, and includes a brief review of its predecessors.
context_section_description: 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. It was to be termed an 'acoustic' or 'mechanical' (non-electrical) telephone.
  1753: Charles Morrison proposes the idea that electricity can be used to transmit messages, by using different wires for each letter.
  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
  28 December 1871: Antonio Meucci files a patent caveat (No. 3353, a notice of intent to invent, but not a formal patent application) at the U.S. Patent Office for a device he named "Sound Telegraph".
  1872: Elisha Gray establishes Western Electric Manufacturing Company.
  1 July 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 Puskás (the inventor of telephone exchange) arrived in the USA.
  6 April 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.
  20 January 1876: Bell signs and notarizes his patent application for the telephone.
  11 February 1876: Elisha Gray designs a liquid transmitter for use with a telephone, but does not build one.
  7 March 1876: Bell's U.S. patent No. 174,465 for the telephone is granted.
  10 March 1876: Bell transmits the sentence: "Mr. Watson, come here! I want to see you!" using a liquid transmitter and an electromagnetic receiver.
  10 August 1876: Using the telegraph line between Brantford and Paris, Ontario, eight miles (thirteen kilometres) distant, Bell makes a telephone call, said by some to be the "world's first long-distance call".
  30 January 1877: Bell's U.S. patent No. 186,787 is granted for an electromagnetic telephone using permanent magnets, iron diaphragms, and a call bell.
  27 April 1877: Edison files for a patent on a carbon (graphite) transmitter. Patent No. 474,230 was granted on 3 May 1892, after a 15-year delay because of litigation. Edison was granted patent No. 222,390 for a carbon granules transmitter in 1879.
  6 October 1877: the Scientific American publishes the invention from Bell - at that time still without a ringer.
  25 October 1877: the article in the Scientific American is discussed at the Telegraphenamt in Berlin
  12 November 1877: The first commercial telephone company enters telephone business in Friedrichsberg close to Berlin using the Siemens pipe as ringer and telephone devices built by Siemens.
  1877: The first experimental Telephone Exchange in Boston.
  1877: First long-distance telephone line
  1877:Emile Berliner invented the telephone transmitter.
  14 January 1878: Bell demonstrates the telephone to Queen Victoria and makes the first publicly-witnessed long-distance calls in the UK. The queen tries the device and finds it to be "quite extraordinary".
  26 January 1878: First permanent telephone connection in UK between two business in Manchester
  28 January 1878: The first commercial US telephone exchange opened in New Haven, Connecticut.
  15 June 1878: The first commercial toll line enters operation, connecting Springfield and Holyoke, Massachusetts
  1887: Tivadar Puskás introduced the multiplex switchboard.
  1915: First U.S. coast-to-coast long-distance telephone call, ceremonially inaugurated by A.G. Bell in New York City and his former assista
caption: Antonio Meucci's telephone.
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