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Encyclopedia > Telecommunication
Copy of the original phone of Alexander Graham Bell at the Musée des Arts et Métiers in Paris
Copy of the original phone of Alexander Graham Bell at the Musée des Arts et Métiers in Paris

Telecommunication is the assisted transmission of signals over a distance for the purpose of communication. In earlier times, this may have involved the use of smoke signals, drums, semaphore, flags, or heliograph. In modern times, telecommunication typically involves the use of electronic transmitters such as the telephone, television, radio or computer. Early inventors in the field of telecommunication include Antonio Meucci, Alexander Graham Bell, Guglielmo Marconi and John Logie Baird. Telecommunication is an important part of the world economy and the telecommunication industry's revenue has been placed at just under 3 percent of the gross world product. Image File history File linksMetadata Download high resolution version (2046x2048, 563 KB) Work by Rama File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Telephone Metadata This file contains additional information, probably added from the digital camera or scanner... Image File history File linksMetadata Download high resolution version (2046x2048, 563 KB) Work by Rama File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Telephone Metadata This file contains additional information, probably added from the digital camera or scanner... Alexander Graham Bell (3 March 1847 – 2 August 1922) was an eminent scientist, inventor and innovator who is credited with the invention of the telephone. ... Foucault pendulum at the Musée des arts et métiers The Musée des Arts et Métiers is a museum in Paris that houses the collection of the Conservatoire National des Arts et Métiers, which was founded in 1794 as a depository for the preservation of scientific... In telecommunications, transmission is the act of transmitting electrical messages (and the associated phenomena of radiant energy that passes through media). ... In the fields of communications, signal processing, and in electrical engineering more generally, a signal is any time-varying quantity. ... For the Bobby Womack album, see Communication (1972 album). ... A smoke signal is a form of visual communication used over a long distance, developed both in the Americas and in China. ... Often invented and used by cultures living in forested areas, drums served as an early form of long distance communication, and were used during ceremonial and religious functions. ... Flag signals can mean any of various methods of using flags or pennants to send signals: Flaghoist signalling or the flaghoist signalling system uses sets of flags and pennants to convey messages. ... Signaling with heliograph, 1910 A heliograph uses a mirror to reflect sunlight to a distant observer. ... For other uses, see Telephone (disambiguation). ... This article is about the machine. ... Antonio Meucci. ... Alexander Graham Bell (3 March 1847 – 2 August 1922) was an eminent scientist, inventor and innovator who is credited with the invention of the telephone. ... For the inventor of radio, see the competing claims in history of radio and the invention of radio. ... For other persons named John Baird, see John Baird (disambiguation). ... Gross world product is the total Gross National Product of all the countries in the world. ...

Contents

Key concepts

Etymology
The word telecommunication was adapted from the French word télécommunication. It is a compound of the Greek prefix tele- (τηλε-), meaning 'far off', and the Latin communicare, meaning 'to share'.[1] The French word télécommunication was coined in 1904 by French engineer and novelist Édouard Estaunié.[2]

Édouard Estaunié (Dijon, February 4, 1862 - Paris, February 1, 1942) was a French novelist. ...

Basic elements

A telecommunication system consists of three basic elements:

For example, in a radio broadcast the broadcast tower is the transmitter, free space is the transmission medium and the radio is the receiver. Often telecommunication systems are two-way with a single device acting as both a transmitter and receiver or transceiver. For example, a mobile phone is a transceiver.[3] Antenna tower of Crystal Palace transmitter, London A transmitter is an electronic device which, usually with the aid of an antenna, propagates an electromagnetic signal such as radio, television, or other telecommunications. ... The ASCII codes for the word Wikipedia represented in binary, the numeral system most commonly used for encoding computer information. ... In the fields of communications, signal processing, and in electrical engineering more generally, a signal is any time-varying quantity. ... A transmission medium is any material substance, such as fiber-optic cable, twisted-wire pair, coaxial cable, dielectric-slab waveguide, water, or air, that can be used for the propagation of signals, usually in the form of modulated radio, light, or acoustic waves, from one point to another. ... In radio terminology, a receiver is an electronic circuit that receives a radio signal from an antenna and decodes the signal for use as sound, pictures, navigational-position information, etc. ... Masts of the Rugby VLF transmitter in England Radio masts and towers are, typically, tall structures designed to support antennas (also known as aerials in the UK) for telecommunications and broadcasting, including television. ... In physics, free space is a concept of electromagnetic theory, corresponding roughly to the vacuum, the baseline state of the electromagnetic field, or the replacement for the electromagnetic aether. ...


Telecommunication over a phone line is called point-to-point communication because it is between one transmitter and one receiver. Telecommunication through radio broadcasts is called broadcast communication because it is between one powerful transmitter and numerous receivers.[3] This article or section does not cite its references or sources. ... Broadcasting is the distribution of audio and/or video signals which transmit programs to an audience. ...


Analogue or digital

Signals can be either analogue or digital. In an analogue signal, the signal is varied continuously with respect to the information. In a digital signal, the information is encoded as a set of discrete values (for example ones and zeros). During transmission the information contained in analogue signals will be degraded by noise. Conversely, unless the noise exceeds a certain threshold, the information contained in digital signals will remain intact. This noise resistance represents a key advantage of digital signals over analogue signals.[4] An analog or analogue signal is any time continuous signal where some time varying feature of the signal is a representation of some other time varying quantity. ... For other uses, see Digital (disambiguation). ...


Networks

A collection of transmitters, receivers or transceivers that communicate with each other is known as a network. Digital networks may consist of one or more routers that route information to the correct user. An analogue network may consist of one or more switches that establish a connection between two or more users. For both types of network, repeaters may be necessary to amplify or recreate the signal when it is being transmitted over long distances. This is to combat attenuation that can render the signal indistinguishable from noise.[5] A telecommunications network is a network of telecommunications links arranged so that messages may be passed from one part of the network to another over multiple links. ... This article describes the computer networking device. ... In the field of telecommunications, a central office houses equipment that is commonly known as simply a switch, which is a piece of equipment that connects phone calls. ... For other uses, see Repeater (disambiguation). ... This article is about Physics. ... This article is about noise as in sound. ...


Channels

A channel is a division in a transmission medium so that it can be used to send multiple streams of information. For example, a radio station may broadcast at 96.1 MHz while another radio station may broadcast at 94.5 MHz. In this case, the medium has been divided by frequency and each channel has received a separate frequency to broadcast on. Alternatively, one could allocate each channel a recurring segment of time over which to broadcast — this is known as time-division multiplexing and is sometimes used in digital communication.[5] Channel, in communications (sometimes called communications channel), refers to the medium used to convey information from a sender (or transmitter) to a receiver. ... For other uses, see Frequency (disambiguation). ... Time-Division Multiplexing (TDM) is a type of digital or (rarely) analog multiplexing in which two or more signals or bit streams are transferred apparently simultaneously as sub-channels in one communication channel, but physically are taking turns on the channel. ...


Modulation

The shaping of a signal to convey information is known as modulation. Modulation can be used to represent a digital message as an analogue waveform. This is known as keying and several keying techniques exist (these include phase-shift keying, frequency-shift keying and amplitude-shift keying). Bluetooth, for example, uses phase-shift keying to exchange information between devices.[6][7] In telecommunications, modulation is the process of varying a periodic waveform, i. ... The word keying has a number of meanings: Junk Keying - Chinese type of ship keying (cryptography) is the installation of key material into a device. ... Phase-shift keying (PSK) is a digital modulation scheme that conveys data by changing, or modulating, the phase of a reference signal (the carrier wave). ... It has been suggested that this article or section be merged with audio frequency-shift keying. ... Amplitude-shift keying (ASK) is a form of modulation which represents digital data as variations in the amplitude of a carrier wave. ... Bluetooth logo This article is about the electronic protocol named after Harald Bluetooth Gormson. ... Phase-shift keying (PSK) is a digital modulation scheme that conveys data by changing, or modulating, the phase of a reference signal (the carrier wave). ...


Modulation can also be used to transmit the information of analogue signals at higher frequencies. This is helpful because low-frequency analogue signals cannot be effectively transmitted over free space. Hence the information from a low-frequency analogue signal must be superimposed on a higher-frequency signal (known as a carrier wave) before transmission. There are several different modulation schemes available to achieve this (two of the most basic being amplitude modulation and frequency modulation). An example of this process is a DJ's voice being superimposed on a 96 MHz carrier wave using frequency modulation (the voice would then be received on a radio as the channel “96 FM”).[8] This article or section does not adequately cite its references or sources. ... Amplitude modulation (AM) is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. ... In telecommunications, frequency modulation (FM) conveys information over a carrier wave by varying its frequency. ... For other meanings of DJ, see DJ (disambiguation). ...


Society and telecommunication

Telecommunication is an important part of modern society. In 2006, estimates placed the telecommunication industry's revenue at $1.2 trillion or just under 3% of the gross world product (official exchange rate).[9] Gross world product is the total Gross National Product of all the countries in the world. ...


On the microeconomic scale, companies have used telecommunication to help build global empires. This is self-evident in the case of online retailer Amazon.com but, according to academic Edward Lenert, even the conventional retailer Wal-Mart has benefited from better telecommunication infrastructure compared to its competitors.[10] In cities throughout the world, home owners use their telephones to organize many home services ranging from pizza deliveries to electricians. Even relatively poor communities have been noted to use telecommunication to their advantage. In Bangladesh's Narshingdi district, isolated villagers use cell phones to speak directly to wholesalers and arrange a better price for their goods. In Cote d'Ivoire, coffee growers share mobile phones to follow hourly variations in coffee prices and sell at the best price.[11] Amazon. ... Wal-Mart Stores, Inc. ... For other uses, see Telephone (disambiguation). ... For the SpongeBob SquarePants episode, see Pizza Delivery (SpongeBob SquarePants). ... For theatrical electricians, see Electrician (theater). ... Côte dIvoire (often called Ivory Coast in English; see below about the name) is a country in West Africa. ...


On the macroeconomic scale, Lars-Hendrik Röller and Leonard Waverman suggested a causal link between good telecommunication infrastructure and economic growth.[12] Few dispute the existence of a correlation although some argue it is wrong to view the relationship as causal.[13]


Due to the economic benefits of good telecommunication infrastructure, there is increasing worry about the digital divide. This is because the world's population does not have equal access to telecommunication systems. A 2003 survey by the International Telecommunication Union (ITU) revealed that roughly one-third of countries have less than 1 mobile subscription for every 20 people and one-third of countries have less than 1 fixed line subscription for every 20 people. In terms of Internet access, roughly half of all countries have less than 1 in 20 people with Internet access. From this information, as well as educational data, the ITU was able to compile an index that measures the overall ability of citizens to access and use information and communication technologies.[14] Using this measure, Sweden, Denmark and Iceland received the highest ranking while the African countries Niger, Burkina Faso and Mali received the lowest.[15] The term digital divide refers to the gap between those people with effective access to digital and information technology, and those without access to it. ... The International Telecommunication Union (ITU; French: Union internationale des télécommunications, Spanish: Unión Internacional de Telecomunicaciones) is an international organization established to standardize and regulate international radio and telecommunications. ...


History

For more details on this topic, see History of telecommunication.

The history of telecommunication predates what is commonly thought of as modern ideas and the systems currently in place today. ...

Early telecommunications

A replica of one of Chappe's semaphore towers.
A replica of one of Chappe's semaphore towers.

Early forms of telecommunication include smoke signals and drums. Drums were used by natives in Africa, New Guinea and South America whereas smoke signals were used by natives in North America and China. Contrary to what one might think, these systems were often used to do more than merely announce the presence of a camp.[16][17] Image File history File linksMetadata Download high resolution version (1200x1600, 580 KB) Other versions of this file File links The following pages link to this file: Telegraphy Claude Chappe Metadata This file contains additional information, probably added from the digital camera or scanner used to create or digitize it. ... Image File history File linksMetadata Download high resolution version (1200x1600, 580 KB) Other versions of this file File links The following pages link to this file: Telegraphy Claude Chappe Metadata This file contains additional information, probably added from the digital camera or scanner used to create or digitize it. ... A smoke signal is a form of visual communication used over a long distance, developed both in the Americas and in China. ... Often invented and used by cultures living in forested areas, drums served as an early form of long distance communication, and were used during ceremonial and religious functions. ... A world map showing the continent of Africa Africa is the worlds second-largest and second most-populous continent, after Asia. ... South America South America is a continent crossed by the equator, with most of its area in the Southern Hemisphere. ... North American redirects here. ...


In the Middle Ages, chains of beacons were commonly used on hilltops as a means of relaying a signal. Beacon chains suffered the drawback that they could only pass a single bit of information, so the meaning of the message such as "The enemy has been sighted" had to be agreed upon in advance. One notable instance of their use was during the Spanish Armada, when a beacon chain relayed a signal from Plymouth to London.[18] This page discusses beacons, fires designed to attract attention. ... Belligerents England Dutch Republic Spain Portugal Commanders Elizabeth I of England Charles Howard Francis Drake Philip II of Spain Duke of Medina Sidonia Strength 34 warships 163 armed merchant vessels 30 Dutch flyboats 22 galleons 108 armed merchant vessels Casualties and losses 50–100 dead[1] ~400 wounded 6,000... This article is about the city in England. ... This article is about the capital of England and the United Kingdom. ...


Homing pigeons have been often been used through history in different cultures. Pigeon post is thought to have Persians roots, and was also used by the Romans to aid their military. Frontinus said that Julius Ceasar used pigeons as messengers in his conquest of Gaul.[19] The Greeks conveyed the names of the victors at the Olympic Games to their various cities by this means.[20] Before the electrical telegraph, this method of communication was used among stockbrokers and financiers. The Dutch government used the system in Java and Sumatra early in the 19th century, the birds being obtained from Baghdad. Reuter started in 1849 a pigeon service to fly stock prices between Aachen and Brussels, a service that operated for a year until the gap in the telegraph link was closed.[21] Homing pigeon The homing pigeon is a variety of domesticated Rock Pigeon (Columba livia) that has been selectively bred to be able to find its way home over extremely long distances. ... Pigeons with messages attached. ... Sextus Julius Frontinus (c. ... This article is about Julius Caesar the Roman dictator. ... Gaul (Latin: ) was the name given, in ancient times, to the region of Western Europe comprising present-day northern Italy, France, Belgium, western Switzerland and the parts of the Netherlands and Germany on the west bank of the Rhine river. ... Telegraphy (from the Greek words tele = far away and grapho = write) is the long distance transmission of written messages without physical transport of letters, originally over wire. ... A stock broker or stockbroker or stock brokerage is someone or a firm who performs transactions in financial instruments on a stock market as an agent of his/her/its clients who are unable or unwilling to trade for themselves. ... Java (Indonesian, Javanese, and Sundanese: Jawa) is an island of Indonesia, and the site of its capital city, Jakarta. ... For other uses, see Sumatra (disambiguation). ... Baghdad (Arabic: ) is the capital of Iraq and of Baghdad Governorate. ... a statue of Reuter in the City of London Paul Julius Baron von Reuter was born July 21, 1816, in Kassel, Germany, as son of a rabbi. ... Oche redirects here; in darts the oche is the line from which players must throw. ... For other places with the same name, see Brussels (disambiguation). ...


In 1792, Claude Chappe, a French engineer, built the first fixed visual telegraphy system (or semaphore line) between Lille and Paris.[22] However semaphore suffered from the need for skilled operators and expensive towers at intervals of ten to thirty kilometres (six to nineteen miles). As a result of competition from the electrical telegraph, the last commercial line was abandoned in 1880.[23] Claude Chappe Claude Chappe (December 25, 1763 – January 23, 1805) was a French inventor who in 1792 demonstrated a practical semaphore system that eventually spanned all of France. ... For other uses, see Lille (disambiguation). ... This article is about the capital of France. ...


Telegraph and telephone

The first commercial electrical telegraph was constructed by Sir Charles Wheatstone and Sir William Fothergill Cooke and opened on 9 April 1839. Both Wheatstone and Cooke viewed their device as "an improvement to the [existing] electromagnetic telegraph" not as a new device.[24] The electrical telegraph is a telegraph that uses electric signals. ... Charles Wheatstone Sir Charles Wheatstone (February 6, 1802 - October 19, 1875) was the British inventor of many innovations including the English concertina the Stereoscope an early form of microphone the Playfair cipher (named for Lord Playfair, the person who publicized it) He was a major figure in the development of... William Fothergill Cooke (Ealing 1806- Farnham, Surrey 25 June 1879) was, with Charles Wheatstone, the co-inventor of the Cooke-Wheatstone electrical telegraph, which was patented in May 1837. ... is the 99th day of the year (100th in leap years) in the Gregorian calendar. ... 1839 (MDCCCXXXIX) was a common year starting on Tuesday (see link for calendar). ...


Samuel Morse independently developed a version of the electrical telegraph that he unsuccessfully demonstrated on 2 September 1837. His code was an important advance over Wheatstone's signaling method. The first transatlantic telegraph cable was successfully completed on 27 July 1866, allowing transatlantic telecommunication for the first time.[25] Portrait of Samuel F. B. Morse by Mathew Brady, between 1855 and 1865 Samuel Finley Breese Morse (April 27, 1791 – April 2, 1872) was an American inventor, and painter of portraits and historic scenes; he is most famous for inventing the electric telegraph and Morse code. ... is the 245th day of the year (246th in leap years) in the Gregorian calendar. ... Queen Victoria, Queen of the United Kingdom (1837 - 1901) 1837 (MDCCCXXXVII) was a common year starting on Sunday (see link for calendar). ... 1922 Chart of the Morse Code Letters and Numerals Morse code is a method for transmitting telegraphic information, using standardized sequences of short and long elements to represent the letters, numerals, punctuation and special characters of a message. ... The first transatlantic telegraph cable crossed the Atlantic Ocean from Foilhommerum, Valentia Island, in western Ireland to Hearts Content, in eastern Newfoundland. ... is the 208th day of the year (209th in leap years) in the Gregorian calendar. ... 1866 (MDCCCLXVI) is a common year starting on Monday of the Gregorian calendar or a common year starting on Wednesday of the 12-day-slower Julian calendar. ...


The conventional telephone was invented independently by Alexander Bell and Elisha Gray in 1876.[26] Antonio Meucci invented the first device that allowed the electrical transmission of voice over a line in 1849. However Meucci's device was of little practical value because it relied upon the electrophonic effect and thus required users to place the receiver in their mouth to “hear” what was being said.[27] The first commercial telephone services were set-up in 1878 and 1879 on both sides of the Atlantic in the cities of New Haven and London.[28][29] Alexander Graham Bell (3 March 1847 – 2 August 1922) was an eminent scientist, inventor and innovator who is credited with the invention of the telephone. ... Elisha Gray (August 2, 1835 – January 21, 1901) was an electrical engineer and is best known for his development of a telephone prototype in 1876 in Highland Park, Illinois, U.S.A.. // Born into a Quaker family in Barnesville, Ohio, Gray was brought up on a farm. ... Antonio Meucci. ... This article is about the city in Connecticut. ... This article is about the capital of England and the United Kingdom. ...


Radio and television

In 1832, James Lindsay gave a classroom demonstration of wireless telegraphy to his students. By 1854, he was able to demonstrate a transmission across the Firth of Tay from Dundee, Scotland to Woodhaven, a distance of two miles (3 km), using water as the transmission medium.[30] In December 1901, Guglielmo Marconi established wireless communication between St. John's, Newfoundland (Canada) and Poldhu, Cornwall (England), earning him the 1909 Nobel Prize in physics (which he shared with Karl Braun).[31] However small-scale radio communication had already been demonstrated in 1893 by Nikola Tesla in a presentation to the National Electric Light Association.[32] James Bowman Lindsay (September 8, 1799 - June 29, 1862) was born in Carmyllie near Arbroath in Angus, Scotland and educated at St. ... Wireless telegraphy is the practice of remote writing (see telegraphy) without the wires normally involved in an electrical telegraph. ... The Firth of Tay is a firth in Scotland between the regions of Fife and City of Dundee into to which Scotlands largest river in terms of flow, the River Tay empties. ... For other uses see Dundee (disambiguation) Dundee is Scotlands fourth largest city, population 154 674 (2001), situated on the North bank of the Firth of Tay. ... Woodhaven used to be a small village between Newport-On-Tay and Wormit in Fife, Scotland but over the years due to expansion of both these villages it is now just the name for harbour. ... For the inventor of radio, see the competing claims in history of radio and the invention of radio. ... Nickname: Motto: Avancez (Go forward) Coordinates: , Country Province Established August 5, 1583 by Royal Charter of Queen Elizabeth I Government  - City Mayor Andy Wells  - Governing body St. ... Poldhu is a small area in south Cornwall, UK, situated on the Lizard Peninsula it comprises Poldhu Point and Poldhu Cove. ... Hannes Alfvén (1908–1995) accepting the Nobel Prize for his work on magnetohydrodynamics [1]. List of Nobel Prize laureates in Physics from 1901 to the present day. ... Karl Ferdinand Braun (6 June 1850 in Fulda, Germany – 20 April 1918 in New York City, U.S.) was a German inventor, physicist and Nobel Prize laureate. ... Nikola Tesla (Serbian Cyrillic: ) (10 July 1856 – 7 January 1943) was a inventor, physicist, mechanical engineer, and electrical engineer. ...


On March 25, 1925, John Logie Baird was able to demonstrate the transmission of moving pictures at the London department store Selfridges. Baird's device relied upon the Nipkow disk and thus became known as the mechanical television. It formed the basis of experimental broadcasts done by the British Broadcasting Corporation beginning September 30, 1929.[33] However, for most of the twentieth century televisions depended upon the cathode ray tube invented by Karl Braun. The first version of such a television to show promise was produced by Philo Farnsworth and demonstrated to his family on September 7, 1927.[34] is the 84th day of the year (85th in leap years) in the Gregorian calendar. ... Year 1925 (MCMXXV) was a common year starting on Thursday (link will display the full calendar) of the Gregorian calendar. ... For other persons named John Baird, see John Baird (disambiguation). ... Selfridges in Birmingham. ... A Nipkow disk is a mechanical, geometrically operating image scanning device (by itself, it performs neither image acquisition or reproduction), invented by Paul Gottlieb Nipkow, which was primarily used as a fundamental component in mechanical television. ... This schematic shows the circular paths traced by the holes in a Nipkow disk. ... This article is an overview article about the Crown chartered British Broadcasting Corporation formed in 1927. ... is the 273rd day of the year (274th in leap years) in the Gregorian calendar. ... Year 1929 (MCMXXIX) was a common year starting on Tuesday (link will display the full calendar) of the Gregorian calendar. ... Karl Ferdinand Braun (6 June 1850 in Fulda, Germany – 20 April 1918 in New York City, U.S.) was a German inventor, physicist and Nobel Prize laureate. ... Philo Taylor Farnsworth (August 19, 1906 – March 11, 1971) was an American inventor. ... is the 250th day of the year (251st in leap years) in the Gregorian calendar. ... Year 1927 (MCMXXVII) was a common year starting on Saturday (link will display full calendar) of the Gregorian calendar. ...


Computer networks and the Internet

On September 11, 1940, George Stibitz was able to transmit problems using teletype to his Complex Number Calculator in New York and receive the computed results back at Dartmouth College in New Hampshire.[35] This configuration of a centralized computer or mainframe with remote dumb terminals remained popular throughout the 1950s. However, it was not until the 1960s that researchers started to investigate packet switching — a technology that would allow chunks of data to be sent to different computers without first passing through a centralized mainframe. A four-node network emerged on December 5, 1969; this network would become ARPANET, which by 1981 would consist of 213 nodes.[36] is the 254th day of the year (255th in leap years) in the Gregorian calendar. ... Year 1940 (MCMXL) was a leap year starting on Monday (link will display the full 1940 calendar) of the Gregorian calendar. ... George Stibitz George Robert Stibitz (April 20, 1904 – January 31, 1995) is internationally recognized as a father of the modern digital computer. ... A teleprinter (teletypewriter, teletype or TTY) is a now largely obsolete electro-mechanical typewriter which can be used to communicate typed messages from point to point through a simple electrical communications channel, often just a pair of wires. ... This article is about the state. ... Dartmouth College is a private, coeducational university located in Hanover, New Hampshire, USA. Incorporated as Trustees of Dartmouth College,[6][7] it is a member of the Ivy League and one of the nine colonial colleges founded before the American Revolution. ... For other uses, see New Hampshire (disambiguation). ... For other uses, see Mainframe. ... In computer networking and telecommunications, packet switching is a communications paradigm in which packets (messages or fragments of messages) are individually routed between nodes, with no previously established communication path. ... is the 339th day of the year (340th in leap years) in the Gregorian calendar. ... Also: 1969 (number) 1969 (movie) 1969 (Stargate SG-1) episode. ... ARPANET logical map, March 1977. ...


ARPANET's development centred around the Request for Comment process and on April 7, 1969, RFC 1 was published. This process is important because ARPANET would eventually merge with other networks to form the Internet and many of the protocols the Internet relies upon today were specified through the Request for Comment process. In September 1981, RFC 791 introduced the Internet Protocol v4 (IPv4) and RFC 793 introduced the Transmission Control Protocol (TCP) — thus creating the TCP/IP protocol that much of the Internet relies upon today. Alternate meaning: Wikipedia:Requests for comment A Request for Comments (RFC) document is one of a series of numbered Internet informational documents and standards very widely followed by both commercial software and freeware in the Internet and Unix communities. ... April 7 is the 97th day of the year in the Gregorian calendar (98th in leap years). ... Also: 1969 (number) 1969 (movie) 1969 (Stargate SG-1) episode. ... The Internet Protocol (IP) is a data-oriented protocol used for communicating data across a packet-switched internetwork. ... The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite. ...


However, not all important developments were made through the Request for Comment process. Two popular link protocols for local area networks (LANs) also appeared in the 1970s. A patent for the token ring protocol was filed by Olof Soderblom on October 29, 1974 and a paper on the Ethernet protocol was published by Robert Metcalfe and David Boggs in the July 1976 issue of Communications of the ACM.[37][38] LAN redirects here. ... Token-Ring local area network (LAN) technology was developed and promoted by IBM in the early 1980s and standardised as IEEE 802. ... Olof Söderblom is the creator of Token Ring networking, and grandson of Nathan Soderblom. ... is the 302nd day of the year (303rd in leap years) in the Gregorian calendar. ... Year 1974 (MCMLXXIV) was a common year starting on Tuesday (link will display full calendar) of the 1974 Gregorian calendar. ... Ethernet is a large, diverse family of frame-based computer networking technologies that operate at many speeds for local area networks (LANs). ... Robert Melancton Metcalfe (born 1946 in Brooklyn, New York) is an American technology pioneer who co-invented Ethernet with David Boggs, founded 3Com and formulated Metcalfes Law. ... Communications of the ACM (CACM) is the flagship monthly magazine of the Association for Computing Machinery. ...


Modern operation

Telephone

Optical fibre provides cheaper bandwidth for long distance communication
Optical fibre provides cheaper bandwidth for long distance communication

In an analogue telephone network, the caller is connected to the person he wants to talk to by switches at various telephone exchanges. The switches form an electrical connection between the two users and the setting of these switches is determined electronically when the caller dials the number. Once the connection is made, the caller's voice is transformed to an electrical signal using a small microphone in the caller's handset. This electrical signal is then sent through the network to the user at the other end where it transformed back into sound by a small speaker in that person's handset. There is a separate electrical connection that works in reverse, allowing the users to converse.[39][40] This is a file from the Wikimedia Commons, a repository of free content hosted by the Wikimedia Foundation. ... This is a file from the Wikimedia Commons, a repository of free content hosted by the Wikimedia Foundation. ... Optical fibers An optical fiber (or fibre) is a glass or plastic fiber designed to guide light along its length. ... The person who (or device that) initiates a telephone call over the public switched telephone network is the calling party. ... central office = Exchange building in the U.S. telephone exchange = Exchange building in the UK, and is also the UK name for a telephone switch, and also has a technical meaning in U.S. telecoms telephone switch is the U.S. term, but is in increasing use in technical UK... Pulse dialing or loop disconnect dialing, also called Rotary or Decadic dialling in the United Kingdom (because up to 10 pulses are sent), is pulsing in which a direct-current pulse train is produced by interrupting a steady signal according to a fixed or formatted code for each digit and... Microphones redirects here. ... A transceiver is a device that has a transmitter and receiver which is combined into a one unit. ... For the Marty Friedman album, see Loudspeaker (album) An inexpensive low fidelity 3. ...


The fixed-line telephones in most residential homes are analogue — that is, the speaker's voice directly determines the signal's voltage. Although short-distance calls may be handled from end-to-end as analogue signals, increasingly telephone service providers are transparently converting the signals to digital for transmission before converting them back to analogue for reception. The advantage of this is that digitized voice data can travel side-by-side with data from the Internet and can be perfectly reproduced in long distance communication (as opposed to analogue signals that are inevitably impacted by noise). A landline or main line is a telephone line which travels through a physical, land-based medium. ...


Mobile phones have had a significant impact on telephone networks. Mobile phone subscriptions now outnumber fixed-line subscriptions in many markets. Sales of mobile phones in 2005 totalled 816.6 million with that figure being almost equally shared amongst the markets of Asia/Pacific (204 m), Western Europe (164 m), CEMEA (Central Europe, the Middle East and Africa) (153.5 m), North America (148 m) and Latin America (102 m).[41] In terms of new subscriptions over the five years from 1999, Africa has outpaced other markets with 58.2% growth.[42] Increasingly these phones are being serviced by systems where the voice content is transmitted digitally such as GSM or W-CDMA with many markets choosing to depreciate analogue systems such as AMPS.[43] For other uses, see GSM (disambiguation). ... W-CDMA (Wideband Code Division Multiple Access) is a type of 3G cellular network. ... AMPS or amps can mean any of the following: Advanced Mobile Phone System, a mobile phone systems technology Advanced Mobile Phone Service, an AT&T company A contraction of amperes, a unit of electrical current The Amps, an indie rock band AMPS, Automated Military Postal System Categories: ...


There have also been dramatic changes in telephone communication behind the scenes. Starting with the operation of TAT-8 in 1988, the 1990s saw the widespread adoption of systems based on optic fibres. The benefit of communicating with optic fibres is that they offer a drastic increase in data capacity. TAT-8 itself was able to carry 10 times as many telephone calls as the last copper cable laid at that time and today's optic fibre cables are able to carry 25 times as many telephone calls as TAT-8.[44] This increase in data capacity is due to several factors: First, optic fibres are physically much smaller than competing technologies. Second, they do not suffer from crosstalk which means several hundred of them can be easily bundled together in a single cable.[45] Lastly, improvements in multiplexing have led to an exponential growth in the data capacity of a single fibre.[46][47] TAT-8 was AT&Ts 8th transatlantic telephone cable, in operation from 1988, initially carrying 40,000 telephone circuits (simultaneous calls) between USA and France. ... Optical fibers An optical fiber (or fibre) is a glass or plastic fiber designed to guide light along its length. ... Look up crosstalk in Wiktionary, the free dictionary. ...


Assisting communication across many modern optic fibre networks is a protocol known as Asynchronous Transfer Mode (ATM). The ATM protocol allows for the side-by-side data transmission mentioned in the second paragraph. It is suitable for public telephone networks because it establishes a pathway for data through the network and associates a traffic contract with that pathway. The traffic contract is essentially an agreement between the client and the network about how the network is to handle the data; if the network cannot meet the conditions of the traffic contract it does not accept the connection. This is important because telephone calls can negotiate a contract so as to guarantee themselves a constant bit rate, something that will ensure a caller's voice is not delayed in parts or cut-off completely.[48] There are competitors to ATM, such as Multiprotocol Label Switching (MPLS), that perform a similar task and are expected to supplant ATM in the future.[49] Asynchronous Transfer Mode (ATM) is a cell relay, packet switching network and data link layer protocol which encodes data traffic into small (53 bytes; 48 bytes of data and 5 bytes of header information) fixed-sized cells. ... If a service (or application) wishes to use a broadband network (an ATM network in particular) to transport a particular kind of traffic, it must first inform the network about what kind of traffic is to be transported, and the performance requirements of that traffic[1]. The application presents this... In computer networking and telecommunications, Multi Protocol Label Switching (MPLS) is a data-carrying mechanism that belongs to the family of packet-switched networks. ...


Radio and television

Digital television standards and their adoption worldwide.
Digital television standards and their adoption worldwide.

In a broadcast system, a central high-powered broadcast tower transmits a high-frequency electromagnetic wave to numerous low-powered receivers. The high-frequency wave sent by the tower is modulated with a signal containing visual or audio information. The antenna of the receiver is then tuned so as to pick up the high-frequency wave and a demodulator is used to retrieve the signal containing the visual or audio information. The broadcast signal can be either analogue (signal is varied continuously with respect to the information) or digital (information is encoded as a set of discrete values).[50][51] Image File history File links Download high resolution version (1350x625, 40 KB) Summary Map showing digital television adoption worldwide. ... Image File history File links Download high resolution version (1350x625, 40 KB) Summary Map showing digital television adoption worldwide. ... Masts of the Rugby VLF transmitter in England Radio masts and towers are, typically, tall structures designed to support antennas (also known as aerials in the UK) for telecommunications and broadcasting, including television. ... Electromagnetic radiation is a propagating wave in space with electric and magnetic components. ... In telecommunications, modulation is the process of varying a periodic waveform, i. ... A Yagi-Uda beam antenna Short Wave Curtain Antenna (Moosbrunn, Austria) A building rooftop supporting numerous dish and sectored mobile telecommunications antennas (Doncaster, Victoria, Australia) An antenna is a transducer designed to transmit or receive radio waves which are a class of electromagnetic waves. ... A modern ATU for ham operators. ... A demodulator is an electronic circuit used to recover the information content from the carrier wave of a signal. ...


The broadcast media industry is at a critical turning point in its development, with many countries moving from analogue to digital broadcasts. This move is made possible by the production of cheaper, faster and more capable integrated circuits. The chief advantage of digital broadcasts is that they prevent a number of complaints with traditional analogue broadcasts. For television, this includes the elimination of problems such as snowy pictures, ghosting and other distortion. These occur because of the nature of analogue transmission, which means that perturbations due to noise will be evident in the final output. Digital transmission overcomes this problem because digital signals are reduced to discrete values upon reception and hence small perturbations do not affect the final output. In a simplified example, if a binary message 1011 was transmitted with signal amplitudes [1.0 0.0 1.0 1.0] and received with signal amplitudes [0.9 0.2 1.1 0.9] it would still decode to the binary message 1011 — a perfect reproduction of what was sent. From this example, a problem with digital transmissions can also be seen in that if the noise is great enough it can significantly alter the decoded message. Using forward error correction a receiver can correct a handful of bit errors in the resulting message but too much noise will lead to incomprehensible output and hence a breakdown of the transmission.[52][53] Integrated circuit of Atmel Diopsis 740 System on Chip showing memory blocks, logic and input/output pads around the periphery Microchips with a transparent window, showing the integrated circuit inside. ... Video noise In video and television, noise refers to the random dot pattern that is superimposed on the picture as a result of electronic noise, the snow that is seen with poor (analog) television reception or on VHS tapes. ... Television interference (ghosting) In television, a ghost is an image on the screen which doesnt belong there, appearing superimposed on the desired image. ... This article is about noise as in sound. ... In telecommunication, forward error correction (FEC) is a system of error control for data transmission, whereby the sender adds redundant data to its messages, which allows the receiver to detect and correct errors (within some bound) without the need to ask the sender for additional data. ...


In digital television broadcasting, there are three competing standards that are likely to be adopted worldwide. These are the ATSC, DVB and ISDB standards; the adoption of these standards thus far is presented in the captioned map. All three standards use MPEG-2 for video compression. ATSC uses Dolby Digital AC-3 for audio compression, ISDB uses Advanced Audio Coding (MPEG-2 Part 7) and DVB has no standard for audio compression but typically uses MPEG-1 Part 3 Layer 2.[54][55] The choice of modulation also varies between the schemes. In digital audio broadcasting, standards are much more unified with practically all countries choosing to adopt the Digital Audio Broadcasting standard (also known as the Eureka 147 standard). The exception being the United States which has chosen to adopt HD Radio. HD Radio, unlike Eureka 147, is based upon a transmission method known as in-band on-channel transmission that allows digital information to "piggyback" on normal AM or FM analogue transmissions.[56] ATSC redirects here. ... Official DVB logo, found on compliant devices DVB, short for Digital Video Broadcasting, is a suite of internationally accepted open standards for digital television. ... Integrated Services Digital Broadcasting (ISDB) is the digital television (DTV) and digital audio broadcasting (DAB) format. ... MPEG-2 is a standard for the generic coding of moving pictures and associated audio information [1]. It is widely used around the world to specify the format of the digital television signals that are broadcast by terrestrial (over-the-air), cable, and direct broadcast satellite TV systems. ... Dolby Digital is the marketing name for a series of lossy audio compression technologies by Dolby Laboratories. ... Advanced Audio Coding (AAC) is a standardized, lossy compression and encoding scheme for digital audio. ... MPEG-1 was an early standard for lossy compression of video and audio. ... Digital Audio Broadcasting (DAB), also known as Eureka 147, is a technology for broadcasting of audio using digital radio transmission. ... Eureka 147 is a protocol for digital radio broadcasting originally developed in Europe, but now being deployed in many countries around the world. ... HD Radio is an in-band on-channel (IBOC) digital radio system created by iBiquity for broadcasting via existing FM and AM radio stations. ... In-band on-channel (IBOC) is a method of transmitting digital radio and analog radio broadcast signals simultaneously on the same frequency. ...


However, despite the pending switch to digital, analogue receivers still remain widespread. Analogue television is still transmitted in practically all countries. The United States had hoped to end analogue broadcasts on December 31, 2006; however, this was recently pushed back to February 17, 2009.[57] For analogue television, there are three standards in use (see a map on adoption here). These are known as PAL, NTSC and SECAM. For analogue radio, the switch to digital is made more difficult by the fact that analogue receivers are a fraction of the cost of digital receivers.[58][59] The choice of modulation for analogue radio is typically between amplitude modulation (AM) or frequency modulation (FM). To achieve stereo playback, an amplitude modulated subcarrier is used for stereo FM. is the 365th day of the year (366th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 48th day of the year in the Gregorian calendar. ... 2009 (MMIX) will be a common year starting on Thursday of the Gregorian calendar. ... Download high resolution version (1276x822, 58 KB) information from sources: [1], [2], NTSC, PAL, SECAM File links The following pages link to this file: NTSC PAL SÉCAM Categories: GFDL images ... For other uses, see PAL (disambiguation). ... NTSC is the analog television system in use in the United States, Canada, Japan, Mexico, the Philippines, South Korea, Taiwan, and some other countries (see map). ... SECAM, also written SÉCAM (Séquentiel couleur à mémoire, French for Sequential Color with Memory), is an analog color television system first used in France. ... Amplitude modulation (AM) is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. ... In telecommunications, frequency modulation (FM) conveys information over a carrier wave by varying its frequency. ... Label for 2. ... FM radio is a broadcast technology invented by Edwin Howard Armstrong that uses frequency modulation to provide high-fidelity broadcast radio sound. ...


The Internet

The Internet is a worldwide network of computers and computer networks that can communicate with each other using the Internet Protocol.[60] Any computer on the Internet has a unique IP address that can be used by other computers to route information to it. Hence, any computer on the Internet can send a message to any other computer using its IP address. These messages carry with them the originating computer's IP address allowing for two-way communication. In this way, the Internet can be seen as an exchange of messages between computers.[61] Image File history File links Osi-model. ... Image File history File links Osi-model. ... The Internet Protocol (IP) is a data-oriented protocol used for communicating data across a packet-switched internetwork. ... An IP address (Internet Protocol address) is a unique address that certain electronic devices currently use in order to identify and communicate with each other on a computer network utilizing the Internet Protocol standard (IP)—in simpler terms, a computer address. ...


An estimated 16.9% of the world population has access to the Internet with the highest access rates (measured as a percentage of the population) in North America (69.7%), Oceania/Australia (53.5%) and Europe (38.9%).[62] In terms of broadband access, Iceland (26.7%), South Korea (25.4%) and the Netherlands (25.3%) lead the world.[63] A WildBlue Satellite Internet dish. ...


The Internet works in part because of protocols that govern how the computers and routers communicate with each other. The nature of computer network communication lends itself to a layered approach where individual protocols in the protocol stack run more-or-less independently of other protocols. This allows lower-level protocols to be customized for the network situation while not changing the way higher-level protocols operate. A practical example of why this is important is because it allows an Internet browser to run the same code regardless of whether the computer it is running on is connected to the Internet through an Ethernet or Wi-Fi connection. Protocols are often talked about in terms of their place in the OSI reference model (pictured on the right), which emerged in 1983 as the first step in an unsuccessful attempt to build a universally adopted networking protocol suite.[64] This article concerns communication between pairs of electronic devices. ... A web browser is a software package that enables a user to display and interact with documents hosted by web servers. ... Ethernet is a large, diverse family of frame-based computer networking technologies that operate at many speeds for local area networks (LANs). ... Wi-Fi (IPA: ) is the common name for a popular wireless technology used in home networks, mobile phones, video games and more. ...


For the Internet, the physical medium and data link protocol can vary several times as packets traverse the globe. This is because the Internet places no constraints on what physical medium or data link protocol is used. This leads to the adoption of media and protocols that best suit the local network situation. In practice, most intercontinental communication will use the Asynchronous Transfer Mode (ATM) protocol (or a modern equivalent) on top of optic fibre. This is because for most intercontinental communication the Internet shares the same infrastructure as the public switched telephone network. Asynchronous Transfer Mode (ATM) is a cell relay, packet switching network and data link layer protocol which encodes data traffic into small (53 bytes; 48 bytes of data and 5 bytes of header information) fixed-sized cells. ... The public switched telephone network (PSTN) is the network of the worlds public circuit-switched telephone networks, in much the same way that the Internet is the network of the worlds public IP-based packet-switched networks. ...


At the network layer, things become standardized with the Internet Protocol (IP) being adopted for logical addressing. For the world wide web, these “IP addresses” are derived from the human readable form using the Domain Name System (e.g. 72.14.207.99 is derived from www.google.com). At the moment, the most widely used version of the Internet Protocol is version four but a move to version six is imminent.[65] The Internet Protocol (IP) is a data-oriented protocol used for communicating data across a packet-switched internetwork. ... [[Image:Link title]] // [[Image:Media:Example. ... The Domain Name System (DNS) associates various sorts of information with domain names; most importantly, it serves as the phone book for the Internet by translating human-readable computer hostnames, e. ...


At the transport layer, most communication adopts either the Transmission Control Protocol (TCP) or the User Datagram Protocol (UDP). TCP is used when it is essential every message sent is received by the other computer where as UDP is used when it is merely desirable. With TCP, packets are retransmitted if they are lost and placed in order before they are presented to higher layers. With UDP, packets are not ordered or retransmitted if lost. Both TCP and UDP packets carry port numbers with them to specify what application or process the packet should be handled by.[66] Because certain application-level protocols use certain ports, network administrators can restrict Internet access by blocking the traffic destined for a particular port. The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite. ... User Datagram Protocol (UDP) is one of the core protocols of the Internet protocol suite. ... It has been suggested that this article or section be merged into Computer port (software). ... In computing, a process is an instance of a computer program that is being executed. ... TCP and UDP are transport protocols used for communication between computers. ...


Above the transport layer, there are certain protocols that are sometimes used and loosely fit in the session and presentation layers, most notably the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols. These protocols ensure that the data transferred between two parties remains completely confidential and one or the other is in use when a padlock appears at the bottom of your web browser.[67] Finally, at the application layer, are many of the protocols Internet users would be familiar with such as HTTP (web browsing), POP3 (e-mail), FTP (file transfer), IRC (Internet chat), BitTorrent (file sharing) and OSCAR (instant messaging). Secure Sockets Layer (SSL) and Transport Layer Security (TLS), its successor, are cryptographic protocols which provide secure communications on the Internet. ... Transport Layer Security (TLS) and its predecessor, Secure Sockets Layer (SSL), are cryptographic protocols that provide secure communications on the Internet for such things as web browsing, e-mail, Internet faxing, instant messaging and other data transfers. ... HTTP (for HyperText Transfer Protocol) is the primary method used to convey information on the World Wide Web. ... Post Office Protocol version 3 (POP3) is an application layer Internet standard protocol used to retrieve email from a remote server to a local client over a TCP/IP connection. ... This article is about the File Transfer Protocol standardised by the IETF. For other file transfer protocols, see File transfer protocol (disambiguation). ... Internet Relay Chat (IRC) is a form of instant communication over the Internet. ... OSCAR is AOLs instant messaging and presence information protocol standing for Open System for CommunicAtion in Realtime. ...


Local area networks

Despite the growth of the Internet, the characteristics of local area networks (computer networks that run at most a few kilometres) remain distinct. This is because networks on this scale do not require all the features associated with larger networks and are often more cost-effective and efficient without them. LAN redirects here. ...


In the mid-1980s, several protocol suites emerged to fill the gap between the data link and applications layer of the OSI reference model. These were Appletalk, IPX and NetBIOS with the dominant protocol suite during the early 1990s being IPX due to its popularity with MS-DOS users. TCP/IP existed at this point but was typically only used by large government and research facilities.[68] As the Internet grew in popularity and a larger percentage of traffic became Internet-related, local area networks gradually moved towards TCP/IP and today networks mostly dedicated to TCP/IP traffic are common. The move to TCP/IP was helped by technologies such as DHCP that allowed TCP/IP clients to discover their own network address — a functionality that came standard with the AppleTalk/IPX/NetBIOS protocol suites.[69] AppleTalk is a proprietary suite of protocols developed by Apple Inc for computer networking. ... See also Ericsson IPX Internetwork Packet Exchange (IPX) is the OSI-model Network layer protocol in the IPX/SPX protocol stack. ... NetBEUI redirects here. ... Microsofts disk operating system, MS-DOS, was Microsofts implementation of DOS, which was the first popular operating system for the IBM PC, and until recently, was widely used on the PC compatible platform. ... The Internet protocol suite is the set of communications protocols that implement the protocol stack on which the Internet runs. ... DHCP in the context of computing can stand for: Dynamic Host Configuration Protocol - one of the protocols in the TCP/IP networking suite Decentralized Hospital Computer Program of the United States Department of Veterans Affairs This article consisting of a 4-letter acronym or initialism is a disambiguation page — a...


It is at the data link layer though that most modern local area networks diverge from the Internet. Whereas Asynchronous Transfer Mode (ATM) or Multiprotocol Label Switching (MPLS) are typical data link protocols for larger networks, Ethernet and Token Ring are typical data link protocols for local area networks. These protocols differ from the former protocols in that they are simpler (e.g. they omit features such as Quality of Service guarantees) and offer collision prevention. Both of these differences allow for more economic set-ups.[70] Asynchronous Transfer Mode (ATM) is a cell relay, packet switching network and data link layer protocol which encodes data traffic into small (53 bytes; 48 bytes of data and 5 bytes of header information) fixed-sized cells. ... In computer networking and telecommunications, Multi Protocol Label Switching (MPLS) is a data-carrying mechanism that belongs to the family of packet-switched networks. ... Ethernet is a large, diverse family of frame-based computer networking technologies that operate at many speeds for local area networks (LANs). ... IBM token ring refers to IBMs implementation of token ring technology for linking personal computers in a local area network (LAN). ... In the fields of packet-switched networks and computer networking, the traffic engineering term Quality of Service, abbreviated QoS, refers to resource reservation control mechanisms. ... In computer networking, Carrier Sense Multiple Access With Collision Detection (CSMA/CD) is a network control protocol in which a carrier sensing scheme is used and a transmitting data station that detects another signal while transmitting a frame, stops transmitting that frame, transmits a jam signal, and then waits for...


Despite the modest popularity of Token Ring in the 80's and 90's, virtually all local area networks now use wired or wireless Ethernet. At the physical layer, most wired Ethernet implementations use copper twisted-pair cables (including the common 10BASE-T networks). However, some early implementations used coaxial cables and some recent implementations (especially high-speed ones) use optic fibres. Optic fibres are also likely to feature prominently in the forthcoming 10-gigabit Ethernet implementations.[71] Where optic fibre is used, the distinction must be made between multi-mode fibre and single-mode fibre. Multi-mode fibre can be thought of as thicker optical fibre that is cheaper to manufacture but that suffers from less usable bandwidth and greater attenuation (i.e. poor long-distance performance).[72] IBM token ring refers to IBMs implementation of token ring technology for linking personal computers in a local area network (LAN). ... Ethernet is a large, diverse family of frame-based computer networking technologies that operate at many speeds for local area networks (LANs). ... 25 Pair Color Code Chart 10BASE-T UTP Cable Twisted pair cabling is a common form of wiring in which two conductors are wound around each other for the purposes of cancelling out electromagnetic interference known as crosstalk. ... 10BASE-T cable 10BASE-T plug 10BASE-T is an implementation of Ethernet which allows stations to be attached via twisted pair cable. ... Coaxial Cable For the weapon, see coaxial weapon. ... Fiber Optic strands An optical fiber in American English or fibre in British English is a transparent thin fiber for transmitting light. ... 10-gigabit Ethernet (XGbE or 10GbE) is the most recent (as of 2005) and fastest of the Ethernet standards. ... Multi-mode optical fiber (multimode fiber or MM fiber) is a type of optical fiber mostly used for communication over shorter distances, e. ...


Telecommunications by region

See also

Main list: List of basic telecommunication topics
telecommunication Portal

Telecommunication is the transmission of signals over a distance for the purpose of communication. ... Not to be confused with information technology, information science, or informatics. ... For other uses, see Telephone (disambiguation). ... Motorola HT1000 hand-held two-way radio A two-way radio is a radio that can both transmit and receive (a transceiver), unlike a broadcast receiver which only receives content one way. ... Image File history File links Portal. ...

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The New Oxford American Dictionary (NOAD) is a single-volume dictionary of North American English by the American editors at the Oxford University Press. ... is the 59th day of the year in the Gregorian calendar. ... This article is about the year. ... PDF is an abbreviation with several meanings: Portable Document Format Post-doctoral fellowship Probability density function There also is an electronic design automation company named PDF Solutions. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 159th day of the year (160th in leap years) in the Gregorian calendar. ... ISSN, or International Standard Serial Number, is the unique eight-digit number applied to a periodical publication including electronic serials. ... ISSN, or International Standard Serial Number, is the unique eight-digit number applied to a periodical publication including electronic serials. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 65th day of the year (66th in leap years) in the Gregorian calendar. ... The International Telecommunication Union (ITU; French: Union internationale des télécommunications, Spanish: Unión Internacional de Telecomunicaciones) is an international organization established to standardize and regulate international radio and telecommunications. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 52nd day of the year in the Gregorian calendar. ... (Clockwise from upper left) Time magazine covers from May 7, 1945; July 25, 1969; December 31, 1999; September 14, 2001; and April 21, 2003. ... IEEE Spectrum is a magazine edited by the Institute of Electrical and Electronics Engineers. ... Sony Corporation ) is a Japanese multinational corporation and one of the worlds largest media conglomerates with revenue of $66. ... Official DVB logo, found on compliant devices DVB, short for Digital Video Broadcasting, is a suite of internationally accepted open standards for digital television. ... The Organisation for Economic Co-operation and Development (OECD), (in French: Organisation de coopération et de développement économiques; OCDE) is an international organisation of thirty countries that accept the principles of representative democracy and a free market economy. ...

External links

Look up Telecommunication in
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Telecommunication Indicators Handbook (4621 words)
The importance of telecommunications as a service industry in itself as well as a critical support element for other service industries is now the subject of high level policy formulation in practically every country in the world.
The public telecommunications sector does not include private networks (1) that do not automatically connect to the public network or which have limitations on membership.
Useful for gauging the size of the telecommunications sector vis-a-vis the overall domestic economy (e.g., telecommunications revenues as a percent of GDP).
ICT/Telecommunication Indicators reports (415 words)
The World Telecommunication Development Report (WTDR), first published for the World Telecommunication Development Conference in 1994, features trends in national, regional and international ICT development.
Like the World Telecommunication Development Report, regional reports such as Asia-Pacific Telecommunication Indicators and African Telecommunication Indicators are renowned for identifying regional trends and developments.
The reports provide a comprehensive review of a nation's telecommunication and mass media industries as well as the use of ICTs in different sectors of the economy such as government, education, business and health.
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