Saturday, March 10, 2007

Timeline of the telephone (1876-1878)

11 February 1876 Elisha Gray invents liquid transmitter for use with a telephone, but does not build one.
14 February 1876 (about 9:30 am) Gray or his lawyer brings to the Patent Office Gray's caveat for the telephone. (A caveat was like a patent application without claims to notify the patent office of an invention in process.)
14 February 1876 (about 11:30am) Bell's lawyer brings to the Patent Office Bell's patent application for the telephone. Bell's lawyer requested that it be registered immediately in the cash receipts blotter.
Two hours later Elisha Gray's caveat was registered in the cash blotter. Although his caveat was not a full application, Gray could have converted it into a patent application, but did not do so because of advice from his lawyer and involvement with acoustic telegraphy. The result was that the patent was awarded to Bell. [1]
7 March 1876 Bell's US patent 174,465 for the telephone is granted.
10 March 1876 Bell transmits speech "Mr. Watson, come here, I want to see you." using a liquid transmitter described in Gray's caveat and an electromagnetic receiver described in Gray's July 1875 US patent 166,095.
16 May 1876 Thomas Edison files first patent application for acoustic telegraphy for which US patent 182,996 was granted October 10, 1876.
10 August 1876 Alexander Bell makes worlds first long distance telephone call between Brantford and Paris, Ontario Canada.
October 1876 Thomas Edison tests his first carbon microphone.
20 January 1877 Edison "first succeeded in transmitting over wires many articulated sentences" using carbon granules as a pressure sensitive variable resistance under the pressure of a diaphragm (Josephson, p143).
30 January 1877 Bell's US patent 186,787 is granted for an electro-magnetic telephone using permanent magnets, iron diaphragms, and a call bell.
4 March 1877 Emile Berliner invents a microphone based on "loose contact" between two metal electrodes, an improvement on the Reis telephone, and in April 1877 files a caveat of an invention in process.
27 April 1877 Thomas Edison files telephone patent application. The US patents (474,230, 474,231 and 474,231) were awarded to Edison in 1892 over the competing claims of Alexander Graham Bell, Emile Berliner, Elisha Gray, A E Dolbear, J W McDonagh, G B Richmond, W L W Voeker, J H Irwin and Francis Blake Jr.[2]
Edison's carbon granules transmitter and Bell's electromagnetic receiver were used, with improvements, by the Bell system for many decades thereafter (Josephson, p 146).

4 June 1877 Emile Berliner files telephone patent application that includes a carbon microphone transmitter.
December 1, 1877 Western Union enters the telephone business using Thomas Edison's superior carbon microphone transmitter.
January 1878 First North American telephone exchange opened in New Haven, Connecticut.
4 February 1878 Thomas Edison demonstrates telephone between Menlo Park, New York and Philadelphia, a distance of 210 km.
14 June 1878 The Telephone Company Ltd (Bell's Patents) registered, London. Opened in London 21 August 1879 - Europe's first telephone exchange.
September 12, 1878 The Bell Telephone Co. sues Western Union for infringing Bell's patents.