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...)
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An optical fiber (or fibre in British English) is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to transmit light between the two ends of the fiber and find wide usage in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths (data transfer rates) than electrical cables. Fibers are used instead of metal wires because signals travel along them with less loss; in addition, fibers are immune to electromagnetic interference, a problem from which metal wires suffer. Fibers are also used for illumination and imaging, and are often wrapped in bundles so they may be used to carry light into, or images out of confined spaces, as in the case of a fiberscope. Specially designed fibers are also used for a variety of other applications, some of them being fiber optic sensors and fiber lasers.
Optical fibers typically include a core surrounded by a transparent cladding material with a lower index of refraction. Light is kept in the core by the phenomenon of total internal reflection which causes the fiber to act as a waveguide. Fibers that support many propagation paths or transverse modes are called multi-mode fibers, while those that support a single mode are called single-mode fibers (SMF). Multi-mode fibers generally have a wider core diameter and are used for short-distance communication links and for applications where high power must be transmitted. Single-mode fibers are used for most communication links longer than 1,000 meters (3,300 ft). (Full article...)General images
AT&T magazine advertisement announcing commercial launch of Picturephone service. (from History of videotelephony)
A replica of one of Claude Chappe's semaphore towers (optical telegraph) in Nalbach, Germany (from History of telecommunication)
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 master telephone patent, 174465, granted to Bell, March 7, 1876 (from History of telecommunication)
James Clerk Maxwell (1831-1879), the founder of electromagnetism theory (from History of radio)
Color bars used in a test pattern, sometimes used when no program material is available. (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)
"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 Tandberg T3 high definition telepresence room in use circa 2008, 40 years after the introduction of Picturephone. (from History of videotelephony)
British Post Office engineers inspect Guglielmo Marconi's wireless telegraphy (radio) equipment in 1897. (from History of radio)
1917 wall telephone, open to show magneto and local battery (from History of the telephone)
Naomi ("Joan") Melwit and Norman Banks at the 3KZ microphone, in the late 1930s. (from History of broadcasting)
Lee DeForest broadcasting Columbia phonograph records on pioneering New York station 2XG,in 1916. (from History of broadcasting)
Private conversation, 1910 (from History of the telephone)
Code of letters and symbols for Chappe telegraph (Rees's Cyclopaedia) (from History of telecommunication)
Caricature of Sir John Reith, by the artist, Wooding. (from History of broadcasting)
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)
Charles Logwood broadcasting at station 2XG, New York City, circa November, 1916. (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)
An exposed view of the Picturephone's rear circuit board (courtesy: Richard Diehl) (from History of videotelephony)
Top of cellular telephone tower (from History of the telephone)
DBS satellite dishes. (from History of television)
Antonio Meucci's telephone. (from History of the telephone)
The first mass-produced Czechoslovak TV-set Tesla 4001A (1953-57). (from History of television)
The Philco Predicta, 1958. In the collection of The Children's Museum of Indianapolis (from History of television)
Swedish Prime Minister Tage Erlander using an Ericsson videophone to speak with Lennart Hyland, a popular TV show host (1969) (from History of videotelephony)
Historical marker commemorating the first telephone central office in New York State (1878) (from History of the telephone)
Stock telegraph ticker machine by Thomas Edison (from History of telecommunication)
A French Gower telephone of 1912 at the Musée des Arts et Métiers in Paris (from History of the telephone)
1896 Telephone (Sweden) (from History of the telephone)
Artist's conception: 21st-century videotelephony imagined in the early 20th century (1910) (from History of videotelephony)
Antonio Meucci, 1854, constructed telephone-like devices. (from History of the telephone)
The master telephone patent granted to Bell, 174465, March 10, 1876 (from History of the telephone)
Modern Apple Iphone. This phone is considered a smartphone (from History of the telephone)
"Doc" Herrold is shown at the microphone of KQW, early 1920s. (from History of broadcasting)
Julio Cervera Baviera (from History of radio)
The French Matra videophone (1970) (from History of videotelephony)
Bell prototype telephone stamp(from History of the telephone)
Centennial Issue of 1976
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)
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)
Typical low-cost webcam used with many personal computers (from History of videotelephony)
Guglielmo Marconi. (from History of broadcasting)
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)
The Australian Broadcasting Corporation logo, first introduced in 1975 and based on the Lissajous curve. (from History of broadcasting)
Donald Manson working as an employee of the Marconi Company (England, 1906) (from History of radio)
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)
Around 1920, radio broadcasting started to get popular. A group of women gathered around the radio at the time. (from History of radio)
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)
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)
Elisha Gray, 1876, designed a telephone using a water microphone in Highland Park, Illinois. (from History of the telephone)
A German rotary dial telephone, the W48 (from History of the telephone)
A 19th century acoustic tin can or "lovers' telephone" (from History of the telephone)
Thomas Edison invented the carbon microphone which produced a strong telephone signal. (from History of the telephone)
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)
RCA 630-TS, the first mass-produced television set, which sold in 1946–1947 (from History of television)
Reginald Fessenden, the father of radio broadcasting in the US. (from History of broadcasting)
Heinrich Rudolf Hertz (1856-1894) discovered an important step in the process of radio development called the Hertzian waves. (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)
Ad for the beginning of experimental television broadcasting in New York City by RCA in 1939 (from History of television)
Old Receiver schematic, c.1906 (from History of the telephone)
Baird in 1925 with his televisor equipment and dummies "James" and "Stooky Bill" (right). (from History of television)
Family watching TV, 1958 (from History of television)
Broadcasting pioneer Frank Conrad in a 1921 portrait. (from History of broadcasting)
Tivadar Puskás proposed the telephone switchboard exchange in 1876. (from History of the telephone)
Right side view, housing removed, one of its printed circuit boards exposed (courtesy: Richard Diehl) (from History of videotelephony)
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)
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)
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Selected biography -
Antonio Santi Giuseppe Meucci (/meɪˈuːtʃi/ may-OO-chee, Italian: [anˈtɔːnjo meˈuttʃi]; 13 April 1808 – 18 October 1889) was an Italian inventor and an associate of Giuseppe Garibaldi, a major political figure in the history of Italy. Meucci is best known for developing a voice-communication apparatus that several sources credit as the first telephone.
Meucci set up a form of voice-communication link in his Staten Island, New York, home that connected the second-floor bedroom to his laboratory. He submitted a patent caveat for his telephonic device to the U.S. Patent Office in 1871, but there was no mention of electromagnetic transmission of vocal sound in his caveat. In 1876, Alexander Graham Bell was granted a patent for the electromagnetic transmission of vocal sound by undulatory electric current. Despite the longstanding general crediting of Bell with the accomplishment, the Italian Ministry of Cultural Heritage and Activities supported celebrations of Meucci's 200th birthday in 2008 using the title "Inventore del telefono" (Inventor of the telephone). The U.S. House of Representatives in a resolution in 2002 also acknowledged Meucci's work in the invention of the telephone, although the U.S. Senate did not join the resolution and the interpretation of the resolution is disputed. (Full article...)Did you know (auto-generated) -
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