The Telecommunication Portal
Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information with an immediacy comparable to face-to-face communication. As such, slow communications technologies like postal mail and pneumatic tubes are excluded from the definition. Many transmission media have been used for telecommunications throughout history, from smoke signals, beacons, semaphore telegraphs, signal flags, and optical heliographs to wires and empty space made to carry electromagnetic signals. These paths of transmission may be divided into communication channels for multiplexing, allowing for a single medium to transmit several concurrent communication sessions. Several methods of long-distance communication before the modern era used sounds like coded drumbeats, the blowing of horns, and whistles. Long-distance technologies invented during the 20th and 21st centuries generally use electric power, and include the 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 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 -
The Norwegian Public Safety Network (Norwegian: Nødnett literally Emergency Network) is a public safety network system based on Terrestrial Trunked Radio (TETRA). Nødnett is implemented by the Directorate for Emergency Communication (Norwegian: Direktoratet for nødkommunikasjon). The network is primarily used for internal and interdisciplinary communication by the police, fire departments and health services. Nødnett is also used by several organisations participating in rescue and emergency work. Planning of the network started in 1995 and in 2006 the contract to build it was awarded to Nokia Siemens Networks. As Nokia Siemens Networks was unable to complete the contract, it was passed on to Motorola Solutions in 2012. The critical infrastructure of Nødnett was finished and was operational in all districts of mainland Norway by December 1, 2015.
The network replaced nearly 300 local and regional networks which operated independently for the fire, police and healthcare agencies. Nødnett allows functionality such as authentication, encryption and higher reliability. (Full article...)General images
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British Post Office engineers inspect Guglielmo Marconi's wireless telegraphy (radio) equipment in 1897. (from History of radio) -
Caricature of Sir John Reith, by Wooding (from History of broadcasting) -
Family watching TV, 1958 (from History of television) -
Lee DeForest broadcasting Columbia phonograph records on pioneering New York station 2XG, in 1916 (from History of broadcasting) -
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) -
AT&T magazine advertisement announcing commercial launch of Picturephone service. (from History of videotelephony) -
Reginald Fessenden, the "father" of radio broadcasting in the US (from History of broadcasting) -
RCA 630-TS, the first mass-produced television set, which sold in 1946–1947 (from History of television) -
The 1969 AT&T Mod II Picturephone, the result of decades long R&D at a cost of over $500M. (from History of telecommunication) -
Top of cellular telephone tower (from History of the telephone) -
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The master telephone patent granted to Bell, 174465, March 10, 1876 (from History of the telephone) -
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) -
First television test broadcast transmitted by the NHK Broadcasting Technology Research Institute in May 1939 (from History of television) -
A French Gower telephone of 1912 at the Musée des Arts et Métiers in Paris (from History of the telephone) -
Antonio Meucci, 1854, constructed telephone-like devices. (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) -
Guglielmo Marconi (from History of broadcasting) -
An exposed view of the Picturephone's rear circuit board (courtesy: Richard Diehl) (from History of videotelephony) -
Code of letters and symbols for Chappe telegraph (Rees's Cyclopaedia) (from History of telecommunication) -
Early experiment demonstrating refraction of microwaves by a paraffin lens by John Ambrose Fleming in 1897 (from History of radio) -
Naomi ("Joan") Melwit and Norman Banks at the 3KZ microphone, in the late 1930s (from History of broadcasting) -
1917 wall telephone, open to show magneto and local battery (from History of the telephone) -
Donald Manson working as an employee of the Marconi Company (England, 1906) (from History of radio) -
Manfred von Ardenne in 1933 (from History of television) -
The first mass-produced Czechoslovak TV-set Tesla 4001A (1953–57) (from History of television) -
Old Receiver schematic, c.1906 (from History of the telephone) -
Thomas Edison invented the carbon microphone which produced a strong telephone signal. (from History of the telephone) -
Historical marker commemorating the first telephone central office in New York State (1878) (from History of the telephone) -
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Apple iPhone smartphone (from History of the telephone) -
The French Matra videophone (1970) (from History of videotelephony) -
Artist's conception: 21st-century videotelephony imagined in the early 20th century (1910) (from History of videotelephony) -
The master telephone patent, 174465, granted to Bell, March 7, 1876 (from History of telecommunication)
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The Australian Broadcasting Corporation logo, first introduced in 1975 and based on the Lissajous curve (from History of broadcasting) -
Elisha Gray, 1876, designed a telephone using a water microphone in Highland Park, Illinois. (from History of the telephone) -
Broadcasting pioneer Frank Conrad in a 1921 portrait (from History of broadcasting) -
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Alexander Graham Bell was awarded the first U.S. patent for the invention of the telephone in 1876. (from History of the telephone) -
Baird in 1925 with his televisor equipment and dummies "James" and "Stooky Bill" (right) (from History of television) -
Charles Logwood broadcasting at station 2XG, New York City, circa November, 1916 (from History of broadcasting) -
Philo Farnsworth in 1924 (from History of television) -
Ad for the beginning of experimental television broadcasting in New York City by RCA in 1939 (from History of television) -
Heinrich Rudolf Hertz (1856–1894) proved the existence of electromagnetic radiation. (from History of radio) -
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)
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Antonio Meucci's telephone. (from History of the telephone) -
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 a build an effective crystal radio receiver. (from History of radio) -
The "Kerbango Internet Radio" was the first stand-alone product that let users listen to Internet radio without a computer. (from History of broadcasting) -
A 19th century acoustic tin can or "lovers' telephone" (from History of the telephone) -
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Typical low-cost webcam used with many personal computers (from History of videotelephony) -
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) -
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) -
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) -
The Regency TR-1, which used Texas Instruments' NPN transistors, was the world's first commercially produced transistor radio in 1954. (from History of radio) -
DBS satellite dishes (from History of television) -
An early Smart TV from 2012 running the discontinued Orsay platform (from History of television) -
A replica of one of Claude Chappe's semaphore towers (optical telegraph) in Nalbach, Germany (from History of telecommunication) -
Bell prototype telephone stamp(from History of the telephone)
Centennial Issue of 1976 -
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) -
AT&T Picturephone (Mod II) fully enclosed in its housing, control pad at bottom (courtesy: Richard Diehl) (from History of videotelephony)
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Oliver Lodge's 1894 lectures on Hertz demonstrated how to transmit and detect radio waves. (from History of radio) -
"Doc" Herrold is shown at the microphone of KQW, early 1920s. (from History of broadcasting) -
Color bars used in a test pattern, sometimes used when no program material is available (from History of television) -
Philipp Reis, 1861, constructed the first telephone, today called the Reis telephone. (from History of the telephone) -
The Philco Predicta, 1958. In the collection of The Children's Museum of Indianapolis (from History of television) -
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) -
Private conversation, 1910 (from History of the telephone) -
1896 Telephone (Sweden) (from History of the telephone) -
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) -
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Right side view, housing removed, one of its printed circuit boards exposed (courtesy: Richard Diehl) (from History of videotelephony) -
Swedish Prime Minister Tage Erlander using an Ericsson videophone to speak with Lennart Hyland, a popular TV show host (1969) (from History of videotelephony) -
Reginald Fessenden (around 1906) (from History of radio)
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