Photophone

transmit sound
The photophone is a telecommunications device that allows transmission of speech on a beam of light.wikipedia
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Fiber-optic communication

fiber-opticfiber-optic networkfiber optic communication
The photophone was a precursor to the fiber-optic communication systems that achieved worldwide popular usage starting in the 1980s.
In 1880 Alexander Graham Bell and his assistant Charles Sumner Tainter created a very early precursor to fiber-optic communications, the Photophone, at Bell's newly established Volta Laboratory in Washington, D.C. Bell considered it his most important invention.

Free-space optical communication

laser communicationfree space opticsfree space
The photophone was similar to a contemporary telephone, except that it used modulated light as a means of wireless transmission while the telephone relied on modulated electricity carried over a conductive wire circuit.
In 1880, Alexander Graham Bell and his assistant Charles Sumner Tainter created the photophone, at Bell's newly established Volta Laboratory in Washington, DC.

Franklin School (Washington, D.C.)

Franklin School
On June 3, 1880, Bell's assistant transmitted a wireless voice telephone message from the roof of the Franklin School to the window of Bell's laboratory, some 213 meters (about 700 ft.) away. On March 3, 1947, the centenary of Alexander Graham Bell's birth, the Telephone Pioneers of America dedicated a historical marker on the side of one of the buildings, the Franklin School, which Bell and Sumner Tainter used for their first formal trial involving a considerable distance.
In addition to being an admired educational facility, a on its exterior describes the building's place in the history of telecommunications, noting Alexander Graham Bell's first wireless communication in 1880, where a beam of light was used to transmit a voice message using his newly invented Photophone.

Volta Laboratory and Bureau

Volta LaboratoryVolta BureauVolta Laboratory Association
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.
* the Photophone – an optical, wireless telephone, the precursor to fiber-optic communications (February 1880);

Alexander Graham Bell

BellGraham BellBell, Alexander Graham
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. On March 3, 1947, the centenary of Alexander Graham Bell's birth, the Telephone Pioneers of America dedicated a historical marker on the side of one of the buildings, the Franklin School, which Bell and Sumner Tainter used for their first formal trial involving a considerable distance.
These included 14 for the telephone and telegraph, four for the photophone, one for the phonograph, five for aerial vehicles, four for "hydroairplanes", and two for selenium cells.

Photoacoustic effect

photoacousticSpectrophone
In its initial form, the photophone receiver was also non-electronic, using the photoacoustic effect.
Through his invention, called "photophone", he transmitted vocal signals by reflecting sun-light from a moving mirror to a selenium solar cell receiver.

Charles Sumner Tainter

[Charles Sumner] TainterCharles TainterSumner Tainter
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. On March 3, 1947, the centenary of Alexander Graham Bell's birth, the Telephone Pioneers of America dedicated a historical marker on the side of one of the buildings, the Franklin School, which Bell and Sumner Tainter used for their first formal trial involving a considerable distance.
During this time, Tainter worked with the Bells on several inventions, amongst them the photophone and phonograph, which they developed into the Graphophone, a substantial improvement of Edison's earlier device, for which Tainter received several patents along with the Bells.

Selenium

SeSe 3 selenium poisoning
In its ultimate electronic form, the photophone receiver used a simple selenium cell photodetector at the focus of a parabolic mirror.
The selenium cell was used in the photophone developed by Alexander Graham Bell in 1879.

Radio

radio communicationradio communicationswireless
The telephone itself was still something of a novelty, and radio was decades away from commercialization.
It was first applied to communications in 1881 when, at the suggestion of French scientist Ernest Mercadier, Alexander Graham Bell adopted "radiophone" (meaning "radiated sound") as an alternate name for his photophone optical transmission system.

Mabel Gardiner Hubbard

Mabel BellMabel HubbardMabel
While honeymooning in Europe with his bride Mabel Hubbard, Bell likely read of the newly discovered property of selenium having a variable resistance when acted upon by light, in a paper by Robert Sabine as published in Nature on 25 April 1878.
Elsie May Bell (1878–1964) who married Gilbert Hovey Grosvenor of National Geographic fame, and Marian Hubbard Bell (1880–1962), who was referred to as "Daisy", and who was nearly named Photophone by Bell after her birth.

Wireless telephone

wireless phone
Conducted from the roof of the Franklin School to Bell's laboratory at 1325 'L' Street, this was the world's first formal wireless telephone communication (away from their laboratory), thus making the photophone the world's earliest known voice wireless telephone systems, at least 19 years ahead of the first spoken radio wave transmissions.
Photophone, a device invented jointly by Alexander Graham Bell and his assistant Charles Sumner Tainter in 1880

Ernst Ruhmer

The German physicist Ernst Ruhmer believed that the increased sensitivity of his improved selenium cells, combined with the superior receiving capabilities of professor H. T. Simon's "speaking arc", would make the photophone practical over longer signalling distances.
Ruhmer first gained widespread recognition for his work on improvements to Alexander Graham Bell's optical wireless telephone, the photophone.

Optical sound

opticalexciterfilm soundtrack
Optical sound
Building on the principle first demonstrated by the Photophone of Alexander Graham Bell in 1880, optical sound was developed by several inventors with an interest in wireless communication through transmission of light, primarily for ship-to-ship use.

History of telecommunication

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History of telecommunication
In 1880, Bell and co-inventor Charles Sumner Tainter conducted the world's first wireless telephone call via modulated lightbeams projected by photophones.

Visible light communication

Intelligent photonic communicationvisible light communications
Visible light communication
The history of visible light communications (VLC) dates back to the 1880s in Washington, D.C. when the Scottish-born scientist Alexander Graham Bell invented the photophone, which transmitted speech on modulated sunlight over several hundred meters.

Pioneers, a Volunteer Network

Telephone Pioneers of AmericaTelecom Pioneers
On March 3, 1947, the centenary of Alexander Graham Bell's birth, the Telephone Pioneers of America dedicated a historical marker on the side of one of the buildings, the Franklin School, which Bell and Sumner Tainter used for their first formal trial involving a considerable distance.
They also dedicated a plaque on the wall of the Franklin School at 13th & K Streets NW in Washington, D.C., honoring Bell's invention of the Photophone, the precursor of fibre-optical communications, and which he referred to as his 'greatest invention'. The plaque read:

Forrest Mims

Forrest M. MimsForrest M Mims IIIForrest M. Mims III
The Photophone Centenary commemoration had first been proposed by electronics researcher and writer Forrest M. Mims, who suggested it to Dr. Melville Bell Grosvenor, the inventor's grandson, during a visit to his office at the National Geographic Society.
Bell first demonstrated his Photophone on 3 June 1880.

Telecommunication

telecommunicationscommunicationstelecom
The photophone is a telecommunications device that allows transmission of speech on a beam of light.

Transmission (telecommunications)

transmissiontransmittransmissions
The photophone is a telecommunications device that allows transmission of speech on a beam of light.

Light

visible lightvisiblelight source
The photophone is a telecommunications device that allows transmission of speech on a beam of light.

Invention

inventorinventionsinventors
Bell believed the photophone was his most important invention.

Patent

patentspatent lawpatented
Of the 18 patents granted in Bell's name alone, and the 12 he shared with his collaborators, four were for the photophone, which Bell referred to as his "greatest achievement", telling a reporter shortly before his death that the photophone was "the greatest invention [I have] ever made, greater than the telephone".

Modulation

modulatedmodulatordigital modulation
The photophone was similar to a contemporary telephone, except that it used modulated light as a means of wireless transmission while the telephone relied on modulated electricity carried over a conductive wire circuit.

Electricity

electricalelectricelectrically
The photophone was similar to a contemporary telephone, except that it used modulated light as a means of wireless transmission while the telephone relied on modulated electricity carried over a conductive wire circuit.