The photophone is a telecommunications device that allows transmission of speech on a beam of light. It was invented jointly by Alexander Graham Bell and his assistant Charles Sumner Tainter on February 19, 1880, at Bell's laboratory at 1325 L Street in Washington, D.C. Both were later to become full associates in the Volta Laboratory Association, created and financed by Bell.
A historical plaque on the side of the Franklin School in Washington, D.C. which marks one of the points from which the photophone was demonstrated
A diagram from one of Bell's 1880 papers
A photophone receiver and headset, one half of Bell and Tainter's optical telecommunication system of 1880
Illustration of a photophone transmitter, showing the path of reflected sunlight, before and after being modulated
Alexander Graham Bell was a Scottish-born Canadian-American inventor, scientist and engineer who is credited with patenting the first practical telephone. He also co-founded the American Telephone and Telegraph Company (AT&T) in 1885.
Bell c. 1917
Melville House, the Bells' first home in North America, now a National Historic Site of Canada
Bell, top right, providing pedagogical instruction to teachers at the Boston School for Deaf Mutes, 1871; throughout his life, he referred to himself as "a teacher of the deaf"
Alexander Graham Bell's telephone patent drawing, March 7, 1876
