Portal:Telecommunication
The Telecommunication Portal
Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electrical or electronic means, typically through cables, radio waves, or other communication technologies. These means of transmission may be divided into communication channels for multiplexing, allowing for a single medium to transmit several concurrent communication sessions. Long-distance technologies invented during the 20th and 21st centuries generally use electric power, and include the electrical telegraph, telephone, television, and radio.
Early telecommunication networks used metal wires as the medium for transmitting signals. These networks were used for telegraphy and telephony for many decades. In the first decade of the 20th century, a revolution in wireless communication began with breakthroughs including those made in radio communications by Guglielmo Marconi, who won the 1909 Nobel Prize in Physics. Other early pioneers in electrical and electronic telecommunications include co-inventors of the telegraph Charles Wheatstone and Samuel Morse, numerous inventors and developers of the telephone including Antonio Meucci, Philipp Reis, Elisha Gray and Alexander Graham Bell, inventors of radio Edwin Armstrong and Lee de Forest, as well as inventors of television like Vladimir K. Zworykin, John Logie Baird and Philo Farnsworth.
Since the 1960s, the proliferation of digital technologies has meant that voice communications have gradually been supplemented by data. The physical limitations of metallic media prompted the development of optical fibre. The Internet, a technology independent of any given medium, has provided global access to services for individual users and further reduced location and time limitations on communications. (Full article...)
Selected article -
A transmission medium is a system or substance that can mediate the propagation of signals for the purposes of telecommunication. Signals are typically imposed on a wave of some kind suitable for the chosen medium. For example, data can modulate sound, and a transmission medium for sounds may be air, but solids and liquids may also act as the transmission medium. Vacuum or air constitutes a good transmission medium for electromagnetic waves such as light and radio waves. While a material substance is not required for electromagnetic waves to propagate, such waves are usually affected by the transmission medium they pass through, for instance, by absorption or reflection or refraction at the interfaces between media. Technical devices can therefore be employed to transmit or guide waves. Thus, an optical fiber or a copper cable is used as transmission media.
Electromagnetic radiation can be transmitted through an optical medium, such as optical fiber, or through twisted pair wires, coaxial cable, or dielectric-slab waveguides. It may also pass through any physical material that is transparent to the specific wavelength, such as water, air, glass, or concrete. Sound is, by definition, the vibration of matter, so it requires a physical medium for transmission, as do other kinds of mechanical waves and heat energy. Historically, science incorporated various aether theories to explain the transmission medium. However, it is now known that electromagnetic waves do not require a physical transmission medium, and so can travel through the vacuum of free space. Regions of the insulative vacuum can become conductive for electrical conduction through the presence of free electrons, holes, or ions. (Full article...)
General images
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Ad for the beginning of experimental television broadcasting in New York City by RCA in 1939 (from History of television) -
Right side view, housing removed, one of its printed circuit boards exposed (courtesy: Richard Diehl) (from History of videotelephony) -
1917 wall telephone, open to show magneto and local battery (from History of the telephone) -
Reis's telephone around 1861, first device called telephone (from History of the telephone) -
Reginald Fessenden (around 1906) (from History of radio) -
The first commercial AM Audion vacuum tube radio transmitter, built in 1914 by Lee De Forest who invented the Audion (triode) in 1906 (from History of radio) -
Naomi ("Joan") Melwit and Norman Banks at the 3KZ microphone, in the late 1930s (from History of broadcasting) -
The Marconi Company was formed in England in 1910. The photo shows a typical early scene, from 1906, with Marconi employee Donald Manson at right. (from History of broadcasting) -
Receiver schematic, c.1906 (from History of the telephone) -
Top of cellular telephone tower (from History of the telephone) -
Private conversation, 1910 (from History of the telephone) -
RCA 630-TS, the first mass-produced television set, which sold in 1946–1947 (from History of television) -
Early pioneers of radio science and technology in the United States, including Charles Steinmetz, David Sarnoff, Irving Langmuir, and Alfred Goldsmith in 1921, photographed next to the antenna feed wires of the New Brunswick Marconi Station, one of the first transatlantic radio links. The photo includes Albert Einstein as a visiting guest. (from History of radio) -
Caricature of Sir John Reith, by Wooding (from History of broadcasting) -
Broadcasting pioneer Frank Conrad in a 1921 portrait (from History of broadcasting) -
A replica of one of Claude Chappe's semaphore towers (optical telegraph) in Nalbach, Germany (from History of telecommunication) -
Baird in 1925 with his televisor equipment and dummies "James" and "Stooky Bill" (right) (from History of television) -
DBS satellite dishes (from History of television) -
Guglielmo Marconi (from History of broadcasting) -
An early experiment demonstrating the refraction of microwaves by a paraffin lens by John Ambrose Fleming in 1897 (from History of radio) -
The Nipkow disk. This schematic shows the circular paths traced by the holes, which may also be square for greater precision. The area of the disk outlined in black shows the region scanned. (from History of television) -
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Family watching TV, 1958 (from History of television) -
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Lee DeForest broadcasting Columbia phonograph records on pioneering New York station 2XG, in 1916 (from History of broadcasting) -
The master telephone patent granted to Bell, 174465, March 7, 1876 (from History of the telephone) -
Reginald Fessenden, the "father" of radio broadcasting in the US (from History of broadcasting) -
AT&T magazine advertisement announcing commercial launch of Picturephone service. (from History of videotelephony) -
An exposed view of the Picturephone's rear circuit board (courtesy: Richard Diehl) (from History of videotelephony) -
Historical marker commemorating the first telephone central office in New York State (1878) (from History of the telephone) -
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Philipp Reis, 1861, constructed the first telephone, today called the Reis telephone. (from History of the telephone) -
Bell prototype telephone stamp(from History of the telephone)
Centennial Issue of 1976 -
Elisha Gray, 1876, designed a telephone using a water microphone in Highland Park, Illinois. (from History of the telephone) -
Oliver Lodge's 1894 lectures on Hertz demonstrated how to transmit and detect radio waves. (from History of radio) -
A 19th century acoustic tin can or "lovers' telephone" (from History of the telephone) -
The master telephone patent, 174465, granted to Bell, March 7, 1876 (from History of telecommunication)
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Manfred von Ardenne in 1933 (from History of television) -
Typical low-cost webcam used with many personal computers (from History of videotelephony) -
The first mass-produced Czechoslovak TV-set Tesla 4001A (1953–57) (from History of television) -
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Antonio Meucci, 1849, developing a voice-communication apparatus that several sources credit as the first telephone. (from History of the telephone) -
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Around 1920, radio broadcasting started to get popular. The Brox Sisters, a popular singing group, gathered around the radio at the time. (from History of radio) -
First television test broadcast transmitted by the NHK Broadcasting Technology Research Institute in May 1939 (from History of television) -
The British Broadcasting Corporation's landmark and iconic London headquarters, Broadcasting House, opened in 1932. At right is the 2005 eastern extension, the John Peel wing. (from History of broadcasting) -
The "Kerbango Internet Radio" was the first stand-alone product that let users listen to Internet radio without a computer. (from History of broadcasting) -
AT&T Picturephone (Mod II) fully enclosed in its housing, control pad at bottom (courtesy: Richard Diehl) (from History of videotelephony) -
Apple iPhone smartphone (from History of the telephone) -
1896 telephone (Sweden) (from History of the telephone) -
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Heinrich Rudolf Hertz (1856–1894) proved the existence of electromagnetic radiation. (from History of radio) -
Thomas Edison invented the carbon microphone which produced a strong telephone signal. (from History of the telephone) -
Philo Farnsworth in 1924 (from History of television) -
The earliest photograph of a television picture, showing the face of Oliver Hutchinson in June 1926. The television picture was projected using Baird's television camera. (from History of television) -
Code of letters and symbols for Chappe telegraph (Rees's Cyclopaedia) (from History of telecommunication) -
Artist's conception: 21st-century videotelephony imagined in the early 20th century (1910) (from History of videotelephony) -
Innocenzo Manzetti considered the idea of a telephone in 1844 (from History of the telephone) -
Reconstruction of Aeneas Tacticus' hydraulic telegraph (4th c. B.C.) in Kotsanas Museum of Ancient Greek Technology, Athens, Greece. (from History of telecommunication) -
Emil Voigt, founder of 2KY on behalf of the Labor Council of New South Wales. This photo was taken in earlier days when Voight was a prominent British athlete, and winner of the Gold Medal for the five mile race at the 1908 Summer Olympics in London. (from History of broadcasting) -
A French Gower telephone of 1912 at the Musée des Arts et Métiers in Paris (from History of the telephone) -
Color bars used in a test pattern, sometimes used when no program material is available (from History of television) -
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The Regency TR-1, which used Texas Instruments' NPN transistors, was the world's first commercially produced transistor radio in 1954. Size: 3×5×1.25 inch (7.6×12.7×3.2 cm) (from History of radio) -
Alexander Graham Bell was awarded the first U.S. patent for the invention of the telephone in 1876. (from History of the telephone) -
Swedish Prime Minister Tage Erlander using an Ericsson videophone to speak with Lennart Hyland, a popular TV show host (1969) (from History of videotelephony) -
Charles Logwood broadcasting at station 2XG, New York City, circa November, 1916 (from History of broadcasting) -
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The Australian Broadcasting Corporation logo, first introduced in 1975 and based on the Lissajous curve (from History of broadcasting) -
In the 1920s, the United States government publication, "Construction and Operation of a Simple Homemade Radio Receiving Outfit", showed how almost any person handy with simple tools could build an effective crystal radio receiver. (from History of radio) -
Donald Manson working as an employee of the Marconi Company (England, 1906) (from History of radio)
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An early Smart TV from 2012 running the discontinued Orsay platform (from History of television) -
The Philco Predicta, 1958. In the collection of The Children's Museum of Indianapolis (from History of television) -
The French Matra videophone (1970) (from History of videotelephony) -
The 1969 AT&T Mod II Picturephone, the result of decades long R&D at a cost of over $500M. (from History of telecommunication)
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Replica of the telettrofono at Museo Nazionale Scienza e Tecnologia Leonardo da Vinci of Milan, Italy, invented by Antonio Meucci and credited by several sources as the first telephone. (from History of the telephone) -
The Kyocera VP-210 Visual Phone was the first commercial mobile videophone. The Personal Handy-phone System (PHS) phone was introduced in Japan (1999). (from History of videotelephony) -
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Actor portraying Alexander Graham Bell in a 1932 silent film. Shows Bell's second telephone transmitter (microphone), invented 1876 and first displayed at the Centennial Exposition, Philadelphia. (from History of the telephone) -
"Fiction becomes fact": Imaginary "Edison" combination videophone-television, conceptualized by George du Maurier and published in Punch magazine. The drawing also depicts then-contemporary speaking tubes, used by the parents in the foreground and their daughter on the viewing display (1878). (from History of videotelephony) -
"Doc" Herrold is shown at the microphone of KQW, early 1920s. (from History of broadcasting) -
British Post Office engineers inspect Guglielmo Marconi's wireless telegraphy (radio) equipment in 1897. (from History of radio) -
Tihanyi' Radioskop patent (1926) was recognized as Document of Universal Significance by the UNESCO (from History of television) -
Australian radio sets usually had the positions of radio stations marked on their dials. The illustration is a dial from a transistorised, mains-operated Calstan radio, circa 1960s. (Click image for a high resolution view, with readable callsigns.) (from History of broadcasting)
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Selected biography -
Nikola Tesla (10 July 1856 – 7 January 1943) was a Serbian-American engineer, futurist, and inventor. He is known for his contributions to the design of the modern alternating current (AC) electricity supply system.
Born and raised in the Austrian Empire, Tesla first studied engineering and physics in the 1870s without receiving a degree. He then gained practical experience in the early 1880s working in telephony and at Continental Edison in the new electric power industry. In 1884, he immigrated to the United States, where he became a naturalized citizen. He worked for a short time at the Edison Machine Works in New York City before he struck out on his own. With the help of partners to finance and market his ideas, Tesla set up laboratories and companies in New York to develop a range of electrical and mechanical devices. His AC induction motor and related polyphase AC patents, licensed by Westinghouse Electric in 1888, earned him a considerable amount of money and became the cornerstone of the polyphase system, which that company eventually marketed. (Full article...)
Did you know (auto-generated) -
- ... that after the release of High and Low, director Akira Kurosawa received telephone calls imitating his film that threatened to kidnap his daughter?
- ... that Colin Mackay, the political editor at Scottish Television, was "very sad" when Colin MacKay, the political editor at Scottish Television, died?
- ... that the Fox television network successfully moved to strip an Iowa TV station of its affiliation?
- ... that one of the earliest Ukrainian science fiction novels, written in 1918 by Mykola Chaikovsky, features solar power and a radiotelephone?
- ... that the radio station at Western Washington University interfered with telephone and television services in a campus dormitory?
- ... that the World-Wide Navigational Warning Service divides the entire ocean into just 21 radio areas?
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