Early Developments (1837 – 1956)
(1837) Samuel F.B. Morse demonstrates the telegraph, the first electrically operated machine for distant communications.
(1874) Thomas Alva Edison patents the duplex telegraph, which allows two messages to be transmitted simultaneously over the same wire. Emile Baudot develops a five-level telegraphic coding system.
(1876) Alexander Graham Bell demonstrates his voice telephone at the Centennial Exhibition in Philadelphia. The telephone was invented while Bell was experimenting with ways to teach speech to deaf children as well as his deaf wife.
(1893) Elisha Gray’s Telautograph, an electric writing machine for use with the telephone, is demonstrated at the World’s Fair in Chicago.
(1912) William E. Shaw demonstrates the Talkless Telephone.
(1915) Bell inaugurates transcontinental telephone service in the U.S.
(1920 – 1929) Bell Telephone Laboratories develop the Deaf-Set for hard-of-hearing persons and early prototypes capable of transmiting pictures over telephone lines.
(1948) Bell Laboratories invents transistor, begining trend toward miniature integrated circuit chips in electronic devices such as hearing aids and amplifiers
(1956) AT&T/Western Union first develops a prototype Bell System PicturePhone. Test marketing in Chicago was not successful.