Timeline of the telephone

A Timeline of the history of the telephone.

1849-1875

1849 Antonio Meucci demonstrates a telephone to individuals in Havana. (It is disputed if this is an electric telephone.)
1854 Charles Bourseul publishes a description of a make-break telephone transmitter and receiver but does not construct a working instrument.
1854 Antonio Meucci demonstrates an electric telephone in New York.
1860 Johann Philipp Reis demonstrates a make-break transmitter after the design of Bourseul.
1860 Meucci demonstrates his telephone on Staten Island.
1861 The German Philipp Reis manages transfer voice electrically over a distance of 340 feet, see Reis' telephone.
1871 Antonio Meucci files a patent caveat (a statement of intention to patent).
1872 Elisha Gray founds Western Electric Manufacturing Company.
July 1873 Thomas Alva Edison notes variable resistance in carbon grains due to pressure, but shelves the discovery.
1874 Gray demonstrates his liquid transmitter telephone at the Highland Park Presbyterian Church.
2 June 1875 Bell first transmits voice.
1 July 1875 Bell first uses a bi-directional capable telephone (Both the transmitter and the receiver were identical membrane instruments.)

14 February 1876 Bell files his first patent on the telephone.
- Two hours later Gray files his patent application.
10 march 1876
30 January 1877 Bell patents the tro-dynamic transmitter, receiver telephone
4 March 1877 Emile Berliner patents telephone exchange in Paris, France.
January 1878 First North American telephone exchange opened in New Haven, Connecticut.

1879 Bell merges with the New England Telephone Company to form the National Bell Telephone Company.
10 September 1879 Connolly and McTighe patent a "dial" telephone exchange (limited in the number of lines to the number of positions on the dial.).
1880 National Bell merges with others to form the American Bell Telephone Company.
1885 American Telephone and Telegraph Company AT&T is formed.
1886 Gilliland's Automatic circuit changer is put into service between Worcester and Leicester allowing for the first Operator dialing allowing one operator to run two exchanges.
1899 AT&T becomes the overall holding company for all the Bell companies.
November 2 1889 A. G. Smith patents a telegraph switch which provides for trunks between groups of selectors allowing for the first time, fewer trunks than there are lines, and automatic selection of an idle trunk.
10 March 1891 Almon Strowger patents the Strowger switch the first Automatic telephone exchange.
30 October 1891 The Strowger Automatic Telephone Exchange company is formed.
3 November 1892 The first Strowger switch goes into operation in LaPorte, Indiana with 75 subscribers and capacity for 99.
1915 Vacuum tubes used in coast-to-coast telephone circuits