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 19th, 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...)

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In radio-frequency engineering and communications engineering, a waveguide is a hollow metal pipe used to carry radio waves. This type of waveguide is used as a transmission line mostly at microwave frequencies, for such purposes as connecting microwave transmitters and receivers to their antennas, in equipment such as microwave ovens, radar sets, satellite communications, and microwave radio links.

The group velocity of guided electromagnetic waves (EMW) is a fraction of the speed of light. Propagation in a (metal-pipe) waveguide may be imagined as a zig-zag path, with the EMW being repeatedly reflected between opposite walls of the guide. For the particular case of rectangular waveguide, it is possible to base an exact analysis on this view. Propagation in a dielectric waveguide may be viewed in the same way, with the waves confined to the dielectric by total internal reflection at its surface. Some structures, such as non-radiative dielectric waveguides and the Goubau line, use both metal walls and dielectric surfaces to confine the wave. (Full article...)

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General images

The following are images from various telecommunication-related articles on Wikipedia.

Image 1The 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)
Image 2Family watching TV, 1958 (from History of television)
Image 3The 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)
Image 4The Australian Broadcasting Corporation logo, first introduced in 1975 and based on the Lissajous curve (from History of broadcasting)
Image 5Innocenzo Manzetti considered the idea of a telephone in 1844 (from History of the telephone)
Image 6John Logie Baird in 1925 with his televisor equipment and dummies "James" and "Stooky Bill" (right) (from History of television)
Image 7A replica of one of Claude Chappe's semaphore towers (optical telegraph) in Nalbach, Germany (from History of telecommunication)
Image 8An early Smart TV from 2012 running the discontinued Orsay platform (from History of television)
Image 9Naomi ("Joan") Melwit and Norman Banks at the 3KZ microphone, in the late 1930s (from History of broadcasting)
Image 10Early 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)
Image 11Stock telegraph ticker machine by Thomas Edison (from History of telecommunication)
Image 12Actor 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)
Image 13Manfred von Ardenne in 1933 (from History of television)
Image 14Thomas Edison invented the carbon microphone which produced a strong telephone signal. (from History of the telephone)
Image 15Lee DeForest broadcasting Columbia phonograph records on New York station 2XG, 1916 (from History of broadcasting)
Image 16Historical marker commemorating the first telephone central office in New York State (1878) (from History of the telephone)
Image 17Tihanyi' Radioskop patent (1926) was recognized as Document of Universal Significance by the UNESCO (from History of television)
Image 18Donald Manson working as an employee of the Marconi Company (England, 1906) (from History of radio)
Image 19Antonio Meucci, 1849, developing a voice-communication apparatus that several sources credit as the first telephone. (from History of the telephone)
Image 20DBS satellite dishes (from History of television)
Image 21Private conversation, 1910 (from History of the telephone)
Image 22Code of letters and symbols for Chappe telegraph (Rees's Cyclopaedia) (from History of telecommunication)
Image 23Reis's telephone around 1861, first device called telephone (from History of the telephone)
Image 24Right side view, housing removed, one of its printed circuit boards exposed (courtesy: Richard Diehl) (from History of videotelephony)
Image 25Typical low-cost webcam used with many personal computers (from History of videotelephony)
Image 26Philo Farnsworth in 1924 (from History of television)
Image 27AT&T magazine advertisement announcing commercial launch of Picturephone service. (from History of videotelephony)
Image 28A German rotary dial telephone, the W48 (from History of the telephone)
Image 29Philipp Reis, 1861, constructed the first telephone, today called the Reis telephone. (from History of the telephone)
Image 30An exposed view of the Picturephone's rear circuit board (courtesy: Richard Diehl) (from History of videotelephony)
Image 31Screen idol Rudolph Valentino at the microphone of WSB in Atlanta, 1923 (from History of broadcasting)
Image 32Ferdinand Braun (from History of television)
Image 33"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)
Image 341896 telephone (Sweden) (from History of the telephone)
Image 35Around 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)
$Image 36An early experiment demonstrating the refraction of microwaves by a paraffin lens by John Ambrose Fleming in 1897 (from History of radio)$
Image 36An early experiment demonstrating the refraction of microwaves by a paraffin lens by John Ambrose Fleming in 1897 (from History of radio)
Image 37Broadcasting pioneer Frank Conrad in a 1921 portrait (from History of broadcasting)
Image 38The Philco Predicta, 1958. In the collection of The Children's Museum of Indianapolis (from History of television)
Image 39AT&T Picturephone (Mod II) fully enclosed in its housing, control pad at bottom (courtesy: Richard Diehl) (from History of videotelephony)
Image 40A 19th century acoustic tin can or "lovers' telephone" (from History of the telephone)
Image 41A French Gower telephone of 1912 at the Musée des Arts et Métiers in Paris (from History of the telephone)
Image 42RCA 630-TS, the first mass-produced television set, which sold in 1946–1947 (from History of television)
Image 43Artist's conception: 21st-century videotelephony imagined in the early 20th century (1910) (from History of videotelephony)
Image 44Reginald Fessenden (around 1906) (from History of radio)
Image 45Ferdinand Braun (from History of broadcasting)
Image 46Top of cellular telephone tower (from History of the telephone)
Image 47Reginald Fessenden, the "father" of radio broadcasting in the U.S. (from History of broadcasting)
Image 48The 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)
Image 49Alexander Graham Bell was awarded the first U.S. patent for the invention of the telephone in 1876. (from History of the telephone)
Image 50The 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)
Image 51
Bell prototype telephone stamp
Centennial Issue of 1976
(from History of the telephone)
Image 52Guglielmo Marconi (from History of broadcasting)
Image 53First television test broadcast transmitted by the NHK Broadcasting Technology Research Institute in May 1939 (from History of television)
Image 54Reconstruction of Aeneas Tacticus' hydraulic telegraph (4th c. B.C.) in Kotsanas Museum of Ancient Greek Technology, Athens, Greece. (from History of telecommunication)
Image 551917 wall telephone, open to show magneto and local battery (from History of the telephone)
Image 56Oliver Lodge's 1894 lectures on Hertz demonstrated how to transmit and detect radio waves. (from History of radio)
Image 57Charles Logwood broadcasting at New York station 2XG, 1916 (from History of broadcasting)
Image 58Australian 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, c. 1960s. (Click image for a high resolution view, with readable callsigns.) (from History of broadcasting)
Image 59Tivadar Puskás proposed the telephone switchboard exchange in 1876. (from History of the telephone)
Image 60Color bars used in a test pattern, sometimes used when no program material is available (from History of television)
Image 61Apple iPhone smartphone (from History of the telephone)
Image 62Receiver schematic, c.1906 (from History of the telephone)
Image 63"Doc" Herrold is shown at the microphone of KQW, c. 1925 (from History of broadcasting)
Image 64In 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)
Image 65Heinrich Rudolf Hertz (1856–1894) proved the existence of electromagnetic radiation. (from History of radio)
Image 66The 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)
Image 67Portrait of John Reith, 1st Baron Reith, in 1925, founding director general of the BBC from 1922 to 1938 (from History of broadcasting)
Image 68The 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)
Image 69British Post Office engineers inspect Guglielmo Marconi's wireless telegraphy (radio) equipment in 1897. (from History of radio)
Image 70The French Matra videophone (1970) (from History of videotelephony)
Image 71The first mass-produced Czechoslovak TV-set Tesla 4001A (1953–57) (from History of television)
Image 72The master telephone patent, 174465, granted to Bell, March 7, 1876 (from History of telecommunication)
Image 73The master telephone patent granted to Bell, 174465, March 7, 1876 (from History of the telephone)
Image 74Replica 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)
Image 75Ad for the beginning of experimental television broadcasting in New York City by RCA in 1939 (from History of television)
Image 76Elisha Gray, 1876, designed a telephone using a water microphone in Highland Park, Illinois. (from History of the telephone)
Image 77The 1969 AT&T Mod II Picturephone, the result of decades long R&D at a cost of over $500M. (from History of telecommunication)
Image 78The "Kerbango Internet Radio" was the first stand-alone product that let users listen to Internet radio without a computer. (from History of broadcasting)
Image 79Swedish Prime Minister Tage Erlander using an Ericsson videophone to speak with Lennart Hyland, a popular TV show host (1969) (from History of videotelephony)

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Morse in 1866

Samuel Finley Breese Morse (April 27, 1791 – April 2, 1872) was an American inventor and painter. After establishing his reputation as a portrait painter, Morse, in his middle age, contributed to the invention of a single-wire telegraph system based on European telegraphs. He was a co-developer and the namesake of Morse code in 1837 and helped to develop the commercial use of telegraphy. (Full article...)

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