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Photophone
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. 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.Carson 2007, pg. 76–78Mims 1982, p. 11. Bell believed the photophone was his most important invention. 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 haveever made, greater than the tele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volta Laboratory And Bureau
The Volta Laboratory (also known as the Alexander Graham Bell Laboratory, the Bell Carriage House and the Bell Laboratory) and the Volta Bureau were created in Georgetown (Washington, D.C.), Georgetown neighborhood of Washington, D.C., by Alexander Graham Bell. The Volta Laboratory was founded in 1880–1881 with Charles Sumner Tainter and Bell's cousin, Chichester Bell, for the research and development of telecommunication, phonograph and other technologies. Using funds generated by the Volta Laboratory, Bell later founded the Volta Bureau in 1887 "for the increase and diffusion of knowledge relating to the deafness, deaf", and merged with the American Association for the Promotion and Teaching of Speech to the Deaf (AAPTSD) in 1908. It was renamed as the Alexander Graham Bell Association for the Deaf in 1956 and then the Alexander Graham Bell Association for the Deaf and Hard of Hearing in 1999. Alexander Graham Bell Association for the Deaf and Hard of Hearing website. Retri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Graham Bell
Alexander Graham Bell (; born Alexander Bell; March 3, 1847 – August 2, 1922) was a Scottish-born Canadian Americans, Canadian-American inventor, scientist, and engineer who is credited with patenting the first practical telephone. He also co-founded the AT&T Corporation, American Telephone and Telegraph Company (AT&T) in 1885. Alexander Melville Bell, Bell's father, grandfather, and brother had all been associated with work on elocution and speech, and both his mother and wife were deaf, profoundly influencing Bell's life's work. His research on hearing and speech further led him to experiment with hearing devices, which eventually culminated in his being awarded the first United States patent law, U.S. patent for the telephone, on March 7, 1876. Bell considered his invention an intrusion on his real work as a scientist and refused to have a telephone in his study. Many other inventions marked Bell's later life, including ground-breaking work in Free-space optical commun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fiber-optic Communication
Fiber-optic communication is a form of optical communication for transmitting information from one place to another by sending pulses of infrared or visible light through an optical fiber. The light is a form of carrier wave that is modulated to carry information. Fiber is preferred over electrical cabling when high bandwidth, long distance, or immunity to electromagnetic interference is required. This type of communication can transmit voice, video, and telemetry through local area networks or across long distances. Optical fiber is used by many telecommunications companies to transmit telephone signals, internet communication, and cable television signals. Researchers at Bell Labs have reached a record bandwidth–distance product of over kilometers per second using fiber-optic communication. Background First developed in the 1970s, fiber-optics have revolutionized the telecommunications industry and have played a major role in the advent of the Information Age. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Sumner Tainter
Charles Sumner Tainter (April 25, 1854 – April 20, 1940) was an American scientific instrument maker, engineer and inventor, best known for his collaborations with Alexander Graham Bell, Chichester Bell, Alexander's father-in-law Gardiner Hubbard, and for his significant improvements to Thomas Alva Edison, Thomas Edison's phonograph, resulting in the ''Graphophone'', one version of which was the first Dictaphone. Later in his career Tainter was associated with the International Graphopone Company of West Virginia, and also managed his own research and development laboratory, earning him the title: 'Father Of The Talking Machine' (i.e.: father of the phonograph). Biography Tainter was born in Watertown, Massachusetts, where he attended Public school (government funded), public school. His education was modest, acquiring his knowledge mostly through self-education. In 1873, he took a job with the Alvan Clark & Sons, Alvan Clark and Sons Company producing telescopes in Cambridge, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free-space Optical Communication
Free-space optical communication (FSO) is an optical communication technology that uses light propagating in free space to wirelessly transmit data for telecommunications or computer networking over long distances. "Free space" means air, outer space, vacuum, or something similar. This contrasts with using solids such as optical fiber cable. The technology is useful where the physical connections are impractical due to high costs or other considerations. History Optical communications, in various forms, have been used for thousands of years. The ancient Greeks used a coded alphabetic system of signalling with torches developed by Cleoxenus, Democleitus and Polybius. In the modern era, semaphores and wireless solar telegraphs called heliographs were developed, using coded signals to communicate with their recipients. In 1880, Alexander Graham Bell and his assistant Charles Sumner Tainter created the photophone, at Bell's newly established Volta Laboratory in Washington, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiophone
A radiotelephone (or radiophone), abbreviated RT, is a radio communication system for conducting a conversation; radiotelephony means telephony by radio. It is in contrast to ''radiotelegraphy'', which is radio transmission of telegrams (messages), or ''television'', transmission of moving pictures and sound. The term is related to radio broadcasting, which transmit audio one way to listeners. Radiotelephony refers specifically to two-way radio systems for bidirectional person-to-person voice communication between separated users, such as CB radio or marine radio. In spite of the name, radiotelephony systems are not necessarily connected to or have anything to do with the telephone network, and in some radio services, including GMRS, interconnection is prohibited. Design Mode of emission The word ''phone'' has a long precedent beginning with early US wired voice systems. The term means ''voice'' as opposed to telegraph or Morse code. This would include systems fitting into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mabel Gardiner Hubbard
Mabel Gardiner Hubbard BellEber, Dorothy Harley in ''Dictionary of Canadian Biography'', Vol. 15, University of Toronto/Université Laval, 2003, accessed August 8, 2013.Toward, 1984. (November 25, 1857 – January 3, 1923) was an American businesswoman, and the daughter of Boston lawyer Gardiner Greene Hubbard, Gardiner Green Hubbard. She was the wife of Alexander Graham Bell, inventor of the first practical telephone. From the time of Mabel's courtship with Graham Bell in 1873, until his death in 1922, Mabel became and remained the most significant influence in his life.Winefield, RichardNever the Twain Shall Meet: Bell, Gallaudet, and the Communications Debate Gallaudet University Press, 1987, pp.72–77, , . Folklore held that Bell undertook telecommunication experiments in an attempt to restore her hearing which had been destroyed by disease close to her fifth birthday, leaving her completely Hearing loss, deaf for the remainder of her life. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenium
Selenium is a chemical element; it has symbol (chemistry), symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elemental state or as pure ore compounds in Earth's crust. Selenium ( ) was discovered in 1817 by , who noted the similarity of the new element to the previously discovered tellurium (named for the Earth). Selenium is found in :Sulfide minerals, metal sulfide ores, where it substitutes for sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores. Minerals that are pure selenide or selenate compounds are rare. The chief commercial uses for selenium today are glassmaking and pigments. Selenium is a semiconductor and is used in photocells. Applications in electronics, once important, have been mostly replaced with silicon semiconductor devices. Selenium is still used in a few types of Direct current, DC power surge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrared
Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those of red light (the longest waves in the visible spectrum), so IR is invisible to the human eye. IR is generally (according to ISO, CIE) understood to include wavelengths from around to . IR is commonly divided between longer-wavelength thermal IR, emitted from terrestrial sources, and shorter-wavelength IR or near-IR, part of the solar spectrum. Longer IR wavelengths (30–100 μm) are sometimes included as part of the terahertz radiation band. Almost all black-body radiation from objects near room temperature is in the IR band. As a form of EMR, IR carries energy and momentum, exerts radiation pressure, and has properties corresponding to both those of a wave and of a particle, the photon. It was long known that fires e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
