Portal:Telecommunication
The Telecommunication Portal
Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that feasible with the human voice, but with a similar scale of expediency; thus, slow systems (such as postal mail) are excluded from the field.
The transmission media in telecommunication have evolved through numerous stages of technology, from beacons and other visual signals (such as smoke signals, semaphore telegraphs, signal flags, and optical heliographs), to electrical cable and electromagnetic radiation, including light. Such transmission paths are often divided into communication channels, which afford the advantages of multiplexing multiple concurrent communication sessions. Telecommunication is often used in its plural form.
Other examples of pre-modern long-distance communication included audio messages, such as coded drumbeats, lung-blown horns, and loud whistles. 20th- and 21st-century technologies for long-distance communication usually involve electrical and electromagnetic technologies, such as telegraph, telephone, television and teleprinter, networks, radio, microwave transmission, optical fiber, and communications satellites.
A revolution in wireless communication began in the first decade of the 20th century with the pioneering developments in radio communications by Guglielmo Marconi, who won the Nobel Prize in Physics in 1909, and other notable pioneering inventors and developers in the field of electrical and electronic telecommunications. These included Charles Wheatstone and Samuel Morse (inventors of the telegraph), Antonio Meucci and Alexander Graham Bell (some of the inventors and developers of the telephone, see Invention of the telephone), Edwin Armstrong and Lee de Forest (inventors of radio), as well as Vladimir K. Zworykin, John Logie Baird and Philo Farnsworth (some of the inventors of television).
According to Article 1.3 of the Radio Regulations (RR), telecommunication is defined as « Any transmission, emission or reception of signs, signals, writings, images and sounds or intelligence of any nature by wire, radio, optical, or other electromagnetic systems.» This definition is identical to those contained in the Annex to the Constitution and Convention of the International Telecommunication Union (Geneva, 1992).
The early telecommunication networks were created with copper wires as the physical medium for signal transmission. For many years, these networks were used for basic phone services, namely voice and telegrams. Since the mid-1990s, as the internet has grown in popularity, voice has been gradually supplanted by data. This soon demonstrated the limitations of copper in data transmission, prompting the development of optics. (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 material substance is not required for electromagnetic waves to propagate, such waves are usually affected by the transmission media 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
The "Kerbango Internet Radio" was the first stand-alone product that let users listen to Internet radio without a computer. (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 a build an effective crystal radio receiver. (from History of radio)
Broadcasting pioneer Frank Conrad in a 1921 portrait. (from History of broadcasting)
Swedish Prime Minister Tage Erlander using an Ericsson videophone to speak with Lennart Hyland, a popular TV show host (1969) (from History of videotelephony)
The Philco Predicta, 1958. In the collection of The Children's Museum of Indianapolis (from History of television)
Stock telegraph ticker machine by Thomas Edison (from History of telecommunication)
"Doc" Herrold is shown at the microphone of KQW, early 1920s. (from History of broadcasting)
An exposed view of the Picturephone's rear circuit board (courtesy: Richard Diehl) (from History of videotelephony)
A replica of one of Claude Chappe's semaphore towers (optical telegraph) in Nalbach, Germany (from History of telecommunication)
Thomas Edison invented the carbon microphone which produced a strong telephone signal. (from History of the telephone)
Private conversation, 1910 (from History of the telephone)
Bell prototype telephone stamp(from History of the telephone)
Centennial Issue of 1976
Antonio Meucci, 1854, constructed telephone-like devices. (from History of the telephone)
1896 Telephone (Sweden) (from History of the telephone)
A Tandberg T3 high definition telepresence room in use circa 2008, 40 years after the introduction of Picturephone. (from History of videotelephony)
Historical marker commemorating the first telephone central office in New York State (1878) (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)
A German rotary dial telephone, the W48 (from History of the telephone)
Family watching TV, 1958 (from History of television)
RCA 630-TS, the first mass-produced television set, which sold in 1946–1947 (from History of television)
Actor portraying Alexander Graham Bell in a 1926 silent film. Shows Bell's first telephone transmitter (microphone), invented 1876 and first displayed at the Centennial Exposition, Philadelphia. (from History of the telephone)
Typical low-cost webcam used with many personal computers (from History of videotelephony)
AT&T magazine advertisement announcing commercial launch of Picturephone service. (from History of videotelephony)
Code of letters and symbols for Chappe telegraph (Rees's Cyclopaedia) (from History of telecommunication)
Right side view, housing removed, one of its printed circuit boards exposed (courtesy: Richard Diehl) (from History of videotelephony)
Around 1920, radio broadcasting started to get popular. A group of women gathered around the radio at the time. (from History of radio)
Tivadar Puskás proposed the telephone switchboard exchange in 1876. (from History of the telephone)
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)
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 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)
A 19th century acoustic tin can or "lovers' telephone" (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)
British Post Office engineers inspect Guglielmo Marconi's wireless telegraphy (radio) equipment in 1897. (from History of radio)
The master telephone patent granted to Bell, 174465, March 10, 1876 (from History of the telephone)
The 1969 AT&T Mod II Picturephone, the result of decades long R&D at a cost of over $500M. (from History of telecommunication)
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)
Reginald Fessenden, the father of radio broadcasting in the US. (from History of broadcasting)
Alexander Graham Bell was awarded the first U.S. patent for the invention of the telephone in 1876. (from History of the telephone)
Top of cellular telephone tower (from History of the telephone)
Naomi ("Joan") Melwit and Norman Banks at the 3KZ microphone, in the late 1930s. (from History of broadcasting)
Caricature of Sir John Reith, by the artist, Wooding. (from History of broadcasting)
Elisha Gray, 1876, designed a telephone using a water microphone in Highland Park, Illinois. (from History of the telephone)
Lee DeForest broadcasting Columbia phonograph records on pioneering New York station 2XG,in 1916. (from History of broadcasting)
The French Matra videophone (1970) (from History of videotelephony)
Electrical engineer/inventor Guglielmo Marconi with the spark-gap transmitter (right) and coherer receiver (left) he used in some of his first long distance radiotelegraphy transmissions during the 1890s. (from History of radio)
Heinrich Rudolf Hertz (1856-1894) discovered an important step in the process of radio development called the Hertzian waves. (from History of radio)
Color bars used in a test pattern, sometimes used when no program material is available. (from History of television)
DBS satellite dishes. (from History of television)
The Australian Broadcasting Corporation logo, first introduced in 1975 and based on the Lissajous curve. (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)
1917 wall telephone, open to show magneto and local battery (from History of the telephone)
The first mass-produced Czechoslovak TV-set Tesla 4001A (1953-57). (from History of television)
A French Gower telephone of 1912 at the Musée des Arts et Métiers in Paris (from History of the telephone)
Charles Logwood broadcasting at station 2XG, New York City, circa November, 1916. (from History of broadcasting)
James Clerk Maxwell (1831-1879), the founder of electromagnetism theory (from History of radio)
Old Receiver schematic, c.1906 (from History of the telephone)
Antonio Meucci's telephone. (from History of the telephone)
Julio Cervera Baviera (from History of radio)
Artist's conception: 21st-century videotelephony imagined in the early 20th century (1910) (from History of videotelephony)
Baird in 1925 with his televisor equipment and dummies "James" and "Stooky Bill" (right). (from History of television)
Donald Manson working as an employee of the Marconi Company (England, 1906) (from History of radio)
The master telephone patent, 174465, granted to Bell, March 7, 1876 (from History of telecommunication)
Modern Apple Iphone. This phone is considered a smartphone (from History of the telephone)
Ad for the beginning of experimental television broadcasting in New York City by RCA in 1939 (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)
AT&T Picturephone (Mod II) fully enclosed in its housing, control pad at bottom (courtesy: Richard Diehl) (from History of videotelephony)
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)
Guglielmo Marconi. (from History of broadcasting)
.jpg)
_LCCN2014717186.jpg)
.svg){kind=logo}
Things to do
 |
Here are some tasks awaiting attention:
|
Selected biography -
Nikola Tesla (/ˈtɛslə/ TESS-lə; Serbian Cyrillic: Никола Тесла, pronounced [nǐkola têsla]; 10 July [O.S. 28 June] 1856 – 7 January 1943) was a Serbian-American inventor, electrical engineer, mechanical engineer, and futurist best known for his contributions to the design of the modern alternating current (AC) electricity supply system.
Born and raised in the Austrian Empire, Tesla studied engineering and physics in the 1870s without receiving a degree, gaining practical experience in the early 1880s working in telephony and at Continental Edison in the new electric power industry. In 1884 he emigrated 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 alternating current (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 the Rod Serling–hosted television production The Great Gatsby (1958) was described as being "neither 'Great' nor 'Gatsby'"?
- ... that even though low interest prompted the Associated Students of Montana Tech to cut funding for student radio station KMSM-FM, it still filed to renew the station's license?
- ... that even the manager of Indiana radio station WMCZ confused it with WMEE, leading a federal judge to order the former to change its call sign?
- ... that although Half Alive wrote their song "Still Feel" with the intention of making it unattractive for radio stations, it became their breakout hit?
- ... that just three years after starting radio station WESQ, North Carolina Wesleyan College sold it, partly because of a failure to integrate the station into its curriculum?
- ... that Nathan Safir, general manager of Texas radio station KCOR for 44 years, was credited with being a pioneer in Spanish-language broadcasting in the United States?
Related portals
Topics
Subcategories
Associated Wikimedia
The following Wikimedia Foundation sister projects provide more on this subject:
-
Commons
Free media repository -
Wikibooks
Free textbooks and manuals -
Wikidata
Free knowledge base -
Wikinews
Free-content news -
Wikiquote
Collection of quotations -
Wikisource
Free-content library -
Wikiversity
Free learning tools -
Wiktionary
Dictionary and thesaurus
