Photophone
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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 Februa
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
Radio
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Radio is the technology of communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz and 300 gigahertz. They are generated by an electronic device called a tr
Photophone
…some 50 different methods of modulating and demodulating light beams for optical telephony. The telephone itself was still something of a novelty, and radio was decades away from commercialization. The social resistance to the photophone's futuristic form of communications could be seen in an August 1880…
An antenna farm hosting various radio antennas on Sandia Peak near Albuquerque, New Mexico, United States