119-626: Azercell is an Azerbaijani telecommunications company based in Baku . It is the largest mobile network operator in Azerbaijan . The company is owned by the ruling Aliyev family through offshore companies. In 2008, state shares were transferred to the Aliyev family's companies at a massive discount, effectively costing Azerbaijan's people at least $ 600 million. Azercell Telecom LLC was established in January 1996 as
238-412: A thermionic tube or thermionic valve uses thermionic emission of electrons from a heated cathode for a number of fundamental electronic functions such as signal amplification and current rectification . The simplest vacuum tube, the diode invented in 1904 by John Ambrose Fleming , contains only a heated electron-emitting cathode and an anode. Electrons can only flow in one direction through
357-411: A radio broadcasting station , the station's large power amplifier is the transmitter and the broadcasting antenna is the interface between the power amplifier and the free space channel. The free space channel is the transmission medium and the receiver's antenna is the interface between the free space channel and the receiver. Next, the radio receiver is the destination of the radio signal, where it
476-476: A 'multiplex' or many-ply telegraph, conveying several messages through the same wire at the same time. Each message can either be read by an operator by the sound, or from different tones read by different operators, or a permanent record can be made by the marks drawn on a ribbon of traveling paper by a Morse recorder. On July 27, 1875, Gray was granted U.S. patent 166,096 for "Electric Telegraph for Transmitting Musical Tones" (the harmonic). On February 14, 1876, at
595-500: A 58.55 percent ownership, sold its stake in Azertel to Azerbaijan International Telecom LLC, which is owned by the Republic of Azerbaijan. Azercell announced on 24 May 2012, the launch of services based on the 4G platform . Azercell's 4G network covers all of Baku city and nearby towns. The networks operate on 1800 MHz frequency. MTS The second region where the 4G network got deployed,
714-411: A better price for their goods. In Côte d'Ivoire , coffee growers share mobile phones to follow hourly variations in coffee prices and sell at the best price. On the macroeconomic scale, Lars-Hendrik Röller and Leonard Waverman suggested a causal link between good telecommunication infrastructure and economic growth. Few dispute the existence of a correlation although some argue it is wrong to view
833-438: A caveat for it in 1876. Gray abandoned his caveat and because he did not contest Bell's priority, the examiner approved Bell's patent on March 3, 1876. Gray had filed his caveat for the variable resistance telephone, but Bell was the first to document the idea and test it in a telephone.[88] Antonio Meucci invented a device that allowed the electrical transmission of voice over a line nearly 30 years before in 1849, but his device
952-590: A chronology of his invention of the telephone and tracing the history of the two legal trials involving Meucci and Alexander Graham Bell. They claim that Meucci was the actual inventor of the telephone, and base their argument on reconstructed evidence. What follows, if not otherwise stated, is a summary of their historic reconstruction. The above information was published in the Scientific American Supplement No. 520 of December 19, 1885, based on reconstructions produced in 1885, for which there
1071-441: A connection between two or more users. For both types of networks, 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 the noise. Another advantage of digital systems over analogue is that their output is easier to store in memory, i.e., two voltage states (high and low) are easier to store than
1190-495: A continuous range of states. Telecommunication has a significant social, cultural and economic impact on modern society. In 2008, estimates placed the telecommunication industry 's revenue at US$ 4.7 trillion or just under three per cent of the gross world product (official exchange rate). Several following sections discuss the impact of telecommunication on society. On the microeconomic scale, companies have used telecommunications to help build global business empires. This
1309-523: A cornet solo played in Somerville was very distinctly heard. Still later, a three-part song came over the wire from Somerville, and Mr. Bell told his audience "I will switch off the song from one part of the room to another so that all can hear." At a subsequent lecture in Salem, Massachusetts , communication was established with Boston, eighteen miles distant, and Mr. Watson at the latter place sang "Auld Lang Syne",
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#17328762468611428-447: A description of it was reportedly published in an Italian-language New York newspaper, although no known copy of that newspaper issue or article has survived to the present day. Meucci claimed to have invented a paired electromagnetic transmitter and receiver, where the motion of a diaphragm modulated a signal in a coil by moving an electromagnet, although this was not mentioned in his 1871 U.S. patent caveat . A further discrepancy observed
1547-428: A double electromagnet, in front of which a membrane, stretched on a ring, carried an oblong piece of soft iron cemented to its middle. A funnel-shaped mouthpiece directed the voice sounds upon the membrane, and as it vibrated, the soft iron "armature" induced corresponding currents in the coils of the electromagnet. These currents, after traversing the wire, passed through the receiver which consisted of an electromagnet in
1666-427: A harmonic telegraph, following the examples of Bourseul, Reis, and Gray. Bell's designs employed various on-off-on-off make-break current-interrupters driven by vibrating steel reeds which sent interrupted current to a distant receiver electro-magnet that caused a second steel reed or tuning fork to vibrate. During a June 2, 1875, experiment by Bell and his assistant Thomas Watson , a receiver reed failed to respond to
1785-406: A higher-frequency signal (known as the " carrier wave ") before transmission. There are several different modulation schemes available to achieve this [two of the most basic being amplitude modulation (AM) and frequency modulation (FM)]. An example of this process is a disc jockey's voice being impressed into a 96 MHz carrier wave using frequency modulation (the voice would then be received on
1904-548: A joint venture between the Azerbaijan government and Turkcell , a large Turkish mobile operator. In this arrangement, the Azerbaijan government owned 51% of the operator. Azercell Telecom started its activities on 15 December 1996. Azercell become the second-largest taxpayer operating outside the country's oil sector. In 2004, TeliaSonera , a Swedish company, was involved in negotiations to privatize Azercell. The Azerbaijan government stepped in to block TeliaSonera from privatizing
2023-764: A junction point on the telegraph line to the neighbouring community of Mount Pleasant, which joined it to the Dominion Telegraph office in Brantford, Ontario. The third and most important test was the world's first true long-distance telephone call, placed between Brantford and Paris, Ontario on August 10, 1876. For that long-distance call Alexander Graham Bell set up a telephone using telegraph lines at Robert White's Boot and Shoe Store at 90 Grand River Street North in Paris via its Dominion Telegraph Co. office on Colborne Street. The normal telegraph line between Paris and Brantford
2142-450: A key advantage of digital signals over analogue signals. However, digital systems fail catastrophically when noise exceeds the system's ability to autocorrect. On the other hand, analogue systems fail gracefully: as noise increases, the signal becomes progressively more degraded but still usable. Also, digital transmission of continuous data unavoidably adds quantization noise to the output. This can be reduced, but not eliminated, only at
2261-413: A large dinner party exchanged "....speech, recitations, songs and instrumental music". To bring telephone signals to Melville House, Alexander Graham audaciously "bought up" and "cleaned up" the complete supply of stovepipe wire in Brantford. With the help of two of his parents' neighbours, he tacked the stovepipe wire some 400 metres (a quarter mile) along the top of fence posts from his parents' home to
2380-464: A man speaks near a movable disc sufficiently flexible to lose none of the vibrations of the voice; that this disc alternately makes and breaks the currents from a battery: you may have at a distance another disc which will simultaneously execute the same vibrations.... It is certain that, in a more or less distant future, a speech will be transmitted by electricity. I have made experiments in this direction; they are delicate and demand time and patience, but
2499-792: A new international frequency list and used in conformity with the Radio Regulation". According to the ITU's Radio Regulations adopted in Atlantic City, all frequencies referenced in the International Frequency Registration Board , examined by the board and registered on the International Frequency List "shall have the right to international protection from harmful interference". From a global perspective, there have been political debates and legislation regarding
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#17328762468612618-437: A person's age, interests, sexual preference and relationship status. In this way, these sites can play important role in everything from organising social engagements to courtship . Prior to social networking sites, technologies like short message service (SMS) and the telephone also had a significant impact on social interactions. In 2000, market research group Ipsos MORI reported that 81% of 15- to 24-year-old SMS users in
2737-491: A radio as the channel "96 FM"). In addition, modulation has the advantage that it may use frequency division multiplexing (FDM). A telecommunications network is a collection of transmitters, receivers, and communications channels that send messages to one another. Some digital communications networks contain one or more routers that work together to transmit information to the correct user. An analogue communications network consists of one or more switches that establish
2856-403: A receiver consisting of a stretched diaphragm or drum of goldbeater's skin with an armature of magnetized iron attached to its middle, and free to vibrate in front of the pole of an electromagnet in circuit with the line. A second membrane-device was built for use as a transmitter. This was the "gallows" phone. A few days later they were tried together, one at each end of the line, which ran from
2975-455: A room in the inventor's house, located at 5 Exeter Place in Boston, to the cellar underneath. Bell, in the work room, held one instrument in his hands, while Watson in the cellar listened at the other. Bell spoke into his instrument, "Do you understand what I say?" and Watson answered "Yes". However, the voice sounds were not distinct and the armature tended to stick to the electromagnet pole and tear
3094-469: A service that operated for a year until the gap in the telegraph link was closed. 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
3213-464: A system called visible speech, developed by his father, to teach deaf children. In 1872 Bell founded a school in Boston , Massachusetts , to train teachers of the deaf. The school subsequently became part of Boston University, where Bell was appointed professor of vocal physiology in 1873. As Professor of Vocal Physiology at Boston University , Bell was engaged in training teachers in the art of instructing
3332-411: A telephone network, the caller is connected to the person to whom they wish to talk 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
3451-422: A telephone was Phillip Reis of Germany only musical not articulating. The first person to publicly exhibit a telephone for transmission of articulate speech was A. G. Bell. The first practical commercial telephone for transmission of articulate speech was invented by myself. Telephones used throughout the world are mine and Bell's. Mine is used for transmitting. Bell's is used for receiving. Cyrille Duquet invents
3570-412: A thin disc of iron was fixed in a circular mouthpiece. The disc served as a combined diaphragm and armature. On speaking into the mouthpiece, the iron diaphragm vibrated with the voice in the magnetic field of the bar-magnet pole, and thereby caused undulatory currents in the coil. These currents, after traveling through the wire to the distant receiver, were received in an identical apparatus. This design
3689-442: A tubular metal can having one end partially closed by a thin circular disc of soft iron. When the undulatory current passed through the coil of this electromagnet, the disc vibrated, thereby creating sound waves in the air. This primitive telephone was rapidly improved. The double electromagnet was replaced by a single permanently magnetized bar magnet having a small coil or bobbin of fine wire surrounding one pole, in front of which
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3808-677: A variant of a string telephone that used wire. Meucci has been further credited with the invention of an anti- sidetone circuit. However, examination showed that his solution to sidetone was to maintain two separate telephone circuits and thus use twice as many transmission wires. The anti-sidetone circuit later introduced by Bell Telephone instead canceled sidetone through a feedback process. An American District Telegraph (ADT) laboratory reportedly lost some of Meucci's working models, his wife reportedly disposed of others and Meucci, who sometimes lived on public assistance, chose not to renew his 1871 teletrofono patent caveat after 1874. A resolution
3927-412: A version of the electrical telegraph that he unsuccessfully demonstrated on September 2, 1837. His code was an important advance over Wheatstone's signaling method. The first transatlantic telegraph cable was successfully completed on July 27, 1866, allowing transatlantic telecommunication for the first time. The conventional telephone was patented by Alexander Bell in 1876. Elisha Gray also filed
4046-577: Is adapted from the French, because its written use was recorded in 1904 by the French engineer and novelist Édouard Estaunié . Communication was first used as an English word in the late 14th century. It comes from Old French comunicacion (14c., Modern French communication), from Latin communicationem (nominative communication), noun of action from past participle stem of communicare, "to share, divide out; communicate, impart, inform; join, unite, participate in," literally, "to make common", from communis". At
4165-671: Is called point-to-point communication because it occurs between a transmitter and a receiver. Telecommunication through radio broadcasts is called broadcast communication because it occurs between a powerful transmitter and numerous low-power but sensitive radio receivers. Telecommunications in which multiple transmitters and multiple receivers have been designed to cooperate and share the same physical channel are called multiplex systems . The sharing of physical channels using multiplexing often results in significant cost reduction. Multiplexed systems are laid out in telecommunication networks and multiplexed signals are switched at nodes through to
4284-451: Is called (in the jargon of the field) " quadrature amplitude modulation " (QAM) that are used in high-capacity digital radio communication systems. Modulation can also be used to transmit the information of low-frequency 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 impressed into
4403-434: Is commonly called "keying" —a term derived from the older use of Morse Code in telecommunications—and several keying techniques exist (these include phase-shift keying , frequency-shift keying , and amplitude-shift keying ). The " Bluetooth " system, for example, uses phase-shift keying to exchange information between various devices. In addition, there are combinations of phase-shift keying and amplitude-shift keying which
4522-794: Is converted from electricity to sound. Telecommunication systems are occasionally "duplex" (two-way systems) with a single box of electronics working as both the transmitter and a receiver, or a transceiver (e.g., a mobile phone ). The transmission electronics and the receiver electronics within a transceiver are quite independent of one another. This can be explained by the fact that radio transmitters contain power amplifiers that operate with electrical powers measured in watts or kilowatts, but radio receivers deal with radio powers measured in microwatts or nanowatts . Hence, transceivers have to be carefully designed and built to isolate their high-power circuitry and their low-power circuitry from each other to avoid interference. Telecommunication over fixed lines
4641-481: Is degraded by undesirable noise . Commonly, the noise in a communication system can be expressed as adding or subtracting from the desirable signal via a random process . This form of noise is called additive noise , with the understanding that the noise can be negative or positive at different instances. Unless the additive noise disturbance exceeds a certain threshold, the information contained in digital signals will remain intact. Their resistance to noise represents
4760-609: Is self-evident in the case of online retailer Amazon.com but, according to academic Edward Lenert, even the conventional retailer Walmart has benefited from better telecommunication infrastructure compared to its competitors. In cities throughout the world, home owners use their telephones to order and arrange a variety of home services ranging from pizza deliveries to electricians. Even relatively poor communities have been noted to use telecommunication to their advantage. In Bangladesh 's Narsingdi District , isolated villagers use cellular phones to speak directly to wholesalers and arrange
4879-448: Is separated from its adjacent stations by 200 kHz, and the difference between 200 kHz and 180 kHz (20 kHz) is an engineering allowance for the imperfections in the communication system. In the example above, the "free space channel" has been divided into communications channels according to frequencies , and each channel is assigned a separate frequency bandwidth in which to broadcast radio waves. This system of dividing
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4998-562: Is the Nakhchivan Autonomous Republic . 51% of Azerbaijan's mobile market belongs to Azercell; while its geographical coverage constitutes 94.15% and population coverage is 98.70%. Telecommunications Telecommunication , often used in its plural form or abbreviated as telecom , is the transmission of information with an immediacy comparable to face-to-face communication. As such, slow communications technologies like postal mail and pneumatic tubes are excluded from
5117-449: Is the informational equivalent of two newspaper pages per person per day in 1986, and six entire newspapers per person per day by 2007. Given this growth, telecommunications play an increasingly important role in the world economy and the global telecommunications industry was about a $ 4.7 trillion sector in 2012. The service revenue of the global telecommunications industry was estimated to be $ 1.5 trillion in 2010, corresponding to 2.4% of
5236-756: The Nipkow disk by Paul Nipkow and thus became known as the mechanical television . It formed the basis of experimental broadcasts done by the British Broadcasting Corporation beginning on 30 September 1929. However, for most of the 20th century, televisions depended on the cathode ray tube invented by Karl Ferdinand Braun . The first version of such a television to show promise was produced by Philo Farnsworth and demonstrated to his family on 7 September 1927. After World War II, interrupted experiments resumed and television became an important home entertainment broadcast medium. The type of device known as
5355-440: The spark gap transmitter for radio or mechanical computers for computing, it was the invention of the thermionic vacuum tube that made these technologies widespread and practical, leading to the creation of electronics . In the 1940s, the invention of semiconductor devices made it possible to produce solid-state devices, which are smaller, cheaper, and more efficient, reliable, and durable than thermionic tubes. Starting in
5474-671: The 1932 Plenipotentiary Telegraph Conference and the International Radiotelegraph Conference in Madrid, the two organizations merged to form the International Telecommunication Union (ITU). They defined telecommunication as "any telegraphic or telephonic communication of signs, signals, writing, facsimiles and sounds of any kind, by wire, wireless or other systems or processes of electric signaling or visual signaling (semaphores)." The definition
5593-492: The 1970s. In the 1960s, Paul Baran and, independently, Donald Davies started to investigate packet switching , a technology that sends a message in portions to its destination asynchronously without passing it through a centralized mainframe . A four-node network emerged on 5 December 1969, constituting the beginnings of the ARPANET , which by 1981 had grown to 213 nodes . ARPANET eventually merged with other networks to form
5712-923: The 1st Baron Kelvin). In August 1876 at a meeting of the British Association for the Advancement of Science , Thomson revealed the telephone to the European public. In describing his visit to the Philadelphia Exhibition, Thomson said, "I heard [through the telephone] passages taken at random from the New York newspapers: 'S.S. Cox Has Arrived' (I failed to make out the S.S. Cox); 'The City of New York', 'Senator Morton', 'The Senate Has Resolved To Print A Thousand Extra Copies', 'The Americans In London Have Resolved To Celebrate The Coming Fourth Of July!' All this my own ears heard spoken to me with unmistakable distinctness by
5831-443: The A. Wallis Ellis store in the neighboring community of Mount Pleasant , received and may possibly have transferred his uncle's voice onto a phonautogram , a drawing made on a pen-like recording device that could produce the shapes of sound waves as waveforms onto smoked glass or other media by tracing their vibrations. The next day on August 4 another call was made between Brantford's telegraph office and Melville House, where
5950-461: The ITU was able to compile an index that measures the overall ability of citizens to access and use information and communication technologies. Using this measure, Sweden, Denmark and Iceland received the highest ranking while the African countries Niger , Burkina Faso and Mali received the lowest. Telecommunication has played a significant role in social relationships. Nevertheless, devices like
6069-726: The Internet. While Internet development was a focus of the Internet Engineering Task Force (IETF) who published a series of Request for Comments documents, other networking advancements occurred in industrial laboratories , such as the local area network (LAN) developments of Ethernet (1983), Token Ring (1984) and Star network topology. The effective capacity to exchange information worldwide through two-way telecommunication networks grew from 281 petabytes (PB) of optimally compressed information in 1986 to 471 PB in 1993 to 2.2 exabytes (EB) in 2000 to 65 EB in 2007. This
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#17328762468616188-560: The National Anthem, and "Hail Columbia", while the audience at Salem joined in the chorus. On January 14, 1878, at Osborne House , on the Isle of Wight , Bell demonstrated the device to Queen Victoria , placing calls to Cowes, Southampton and London. These were the first publicly witnessed long-distance telephone calls in the UK . The queen considered the process to be "quite extraordinary" although
6307-463: The Reis equipment and found that "single words, uttered as in reading, speaking and the like, were perceptible indistinctly, notwithstanding here also the inflections of the voice, the modulations of interrogation, wonder, command, etc., attained distinct expression." He used Reis's work for the successful development of the carbon microphone . Edison acknowledged his debt to Reis thus: The first inventor of
6426-733: The US Patent Office, Gray's lawyer filed a patent caveat for a telephone on the very same day that Bell's lawyer filed Bell's patent application for a telephone. The water transmitter described in Gray's caveat was strikingly similar to the experimental telephone transmitter tested by Bell on March 10, 1876, a fact which raised questions about whether Bell (who knew of Gray) was inspired by Gray's design or vice versa. Although Bell did not use Gray's water transmitter in later telephones, evidence suggests that Bell's lawyers may have obtained an unfair advantage over Gray. Alexander Graham Bell had pioneered
6545-499: The United Kingdom had used the service to coordinate social arrangements and 42% to flirt. In cultural terms, telecommunication has increased the public's ability to access music and film. With television, people can watch films they have not seen before in their own home without having to travel to the video store or cinema. With radio and the Internet, people can listen to music they have not heard before without having to travel to
6664-748: The United States was spent on media that depend upon telecommunication. Many countries have enacted legislation which conforms to the International Telecommunication Regulations established by the International Telecommunication Union (ITU), which is the "leading UN agency for information and communication technology issues". In 1947, at the Atlantic City Conference, the ITU decided to "afford international protection to all frequencies registered in
6783-489: The affirmative, and soon was heard a voice singing "America". [...] Going to another instrument, connected by wire with Providence, forty-three miles distant, Mr. Bell listened a moment, and said, "Signor Brignolli, who is assisting at a concert in Providence Music Hall, will now sing for us." In a moment the cadence of the tenor's voice rose and fell, the sound being faint, sometimes lost, and then again audible. Later,
6902-667: The approximations obtained promise a favorable result". An early communicating device was invented around 1854 by Antonio Meucci , who called it a telettrofono ( lit. "electrophone") . In 1871 Meucci filed a patent caveat at the US Patent Office. His caveat describes his invention, but does not mention a diaphragm, electromagnet, conversion of sound into electrical waves, conversion of electrical waves into sound, or other essential features of an electromagnetic telephone. The first American demonstration of Meucci's invention took place in Staten Island , New York in 1854. In 1861,
7021-572: The caller's handset . This electrical signal is then sent through the network to the user at the other end where it is transformed back into sound by a small speaker in that person's handset. Invention of the telephone The invention of the telephone was the culmination of work done by more than one individual, and led to an array of lawsuits relating to the patent claims of several individuals and numerous companies. Notable people included in this were Antonio Meucci , Philipp Reis , Elisha Gray and Alexander Graham Bell . The concept of
7140-471: The complex timbre, amplitude, and frequencies of speech at a distance. After Bell and Watson discovered on June 2, 1875, that movements of the reed alone in a magnetic field could reproduce the frequencies and timbre of spoken sound waves, Bell reasoned by analogy with the mechanical phonautograph that a skin diaphragm would reproduce sounds like the human ear when connected to a steel or iron reed or hinged armature. On July 1, 1875, he instructed Watson to build
7259-437: The correct destination terminal receiver. Communications can be encoded as analogue or digital signals , which may in turn be carried by analogue or digital communication systems. Analogue signals vary continuously with respect to the information, while digital signals encode information as a set of discrete values (e.g., a set of ones and zeroes). During propagation and reception, information contained in analogue signals
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#17328762468617378-506: The current, which at the other end of the line passed through electromagnets and vibrated matching tuned steel reeds near the electromagnet poles. Gray's "harmonic telegraph", with vibrating reeds, was used by the Western Union Telegraph Company. Since more than one set of vibration frequencies – that is to say, more than one musical tone – can be sent over the same wire simultaneously, the harmonic telegraph can be utilized as
7497-574: The deaf how to speak and experimented with the Leon Scott phonautograph in recording the vibrations of speech. This apparatus consists essentially of a thin membrane vibrated by the voice and carrying a light-weight stylus, which traces an undulatory line on a plate of smoked glass . The line is a graphic representation of the vibrations of the membrane and the waves of sound in the air. This background prepared Bell for work with spoken sound waves and electricity. He began his experiments in 1873–1874 with
7616-500: The definition. Many transmission media have been used for telecommunications throughout history, from smoke signals , beacons , semaphore telegraphs , signal flags , and optical heliographs to wires and empty space made to carry electromagnetic signals. These paths of transmission may be divided into communication channels for multiplexing , allowing for a single medium to transmit several concurrent communication sessions . Several methods of long-distance communication before
7735-511: The development of optical fibre. The Internet , a technology independent of any given medium, has provided global access to services for individual users and further reduced location and time limitations on communications. Telecommunication is a compound noun of the Greek prefix tele- (τῆλε), meaning distant , far off , or afar , and the Latin verb communicare , meaning to share . Its modern use
7854-537: The device—from the cathode to the anode. Adding one or more control grids within the tube enables the current between the cathode and anode to be controlled by the voltage on the grid or grids. These devices became a key component of electronic circuits for the first half of the 20th century and were crucial to the development of radio, television, radar, sound recording and reproduction , long-distance telephone networks, and analogue and early digital computers . While some applications had used earlier technologies such as
7973-422: The electrical telegraph, the last commercial line was abandoned in 1880. On July 25, 1837, the first commercial electrical telegraph was demonstrated by English inventor Sir William Fothergill Cooke and English scientist Sir Charles Wheatstone . Both inventors viewed their device as "an improvement to the [existing] electromagnetic telegraph" and not as a new device. Samuel Morse independently developed
8092-403: The expense of increasing the channel bandwidth requirement. The term "channel" has two different meanings. In one meaning, a channel is the physical medium that carries a signal between the transmitter and the receiver. Examples of this include the atmosphere for sound communications, glass optical fibres for some kinds of optical communications , coaxial cables for communications by way of
8211-492: The field of aviation. Bell himself claimed that the telephone was invented in Canada but made in the United States. The first successful bi-directional transmission of clear speech by Bell and Watson was made on March 10, 1876, when Bell spoke into the device, "Mr. Watson, come here, I want to see you." and Watson complied with the request. Bell tested Gray's liquid transmitter design in this experiment, but only after Bell's patent
8330-453: The first decade of the 20th century, a revolution in wireless communication began with breakthroughs including those made in radio communications by Guglielmo Marconi , who won the 1909 Nobel Prize in Physics . Other early pioneers in electrical and electronic telecommunications include co-inventors of the telegraph Charles Wheatstone and Samuel Morse , numerous inventors and developers of
8449-652: The future impact of these communication firsts". A later telephone design was publicly exhibited on May 4, 1877, at a lecture given by Professor Bell in the Boston Music Hall . According to a report quoted by John Munro in Heroes of the Telegraph : Going to the small telephone box with its slender wire attachments, Mr. Bell coolly asked, as though addressing someone in an adjoining room, "Mr. Watson, are you ready!" Mr. Watson, five miles away in Somerville, promptly answered in
8568-503: The handset. Duquet obtained a patent on 1 Feb. 1878 for a number of modifications "giving more facility for the transmission of sound and adding to its acoustic properties," and in particular for the design of a new apparatus combining the speaker and receiver in a single unit. Elisha Gray , of Highland Park, Illinois , also devised a tone telegraph of this kind about the same time as La Cour. In Gray's tone telegraph, several vibrating steel reeds tuned to different frequencies interrupted
8687-473: The idea of a telephone as early as 1844, and may have made one in 1864, as an enhancement to an automaton built by him in 1849. Charles Bourseul was a French telegraph engineer who proposed (but did not build) the first design of a "make-and-break" telephone in 1854. That is about the same time that Meucci later claimed to have created his first attempt at the telephone in Italy. Bourseul explained: "Suppose that
8806-431: The importance of social conversations and staying connected to family and friends. Since then the role that telecommunications has played in social relations has become increasingly important. In recent years, the popularity of social networking sites has increased dramatically. These sites allow users to communicate with each other as well as post photographs, events and profiles for others to see. The profiles can list
8925-500: The intermittent current supplied by an electric battery. Bell told Watson, who was at the other end of the line, to pluck the reed, thinking it had stuck to the pole of the magnet. Watson complied, and to his astonishment Bell heard a reed at his end of the line vibrate and emit the same timbre of a plucked reed, although there were no interrupted on-off-on-off currents from a transmitter to make it vibrate. A few more experiments soon showed that his receiver reed had been set in vibration by
9044-598: The inventor of the telephone. Others in Canada disagreed with the Congressional resolution, some of whom provided criticisms of both its accuracy and intent. A retired director general of the Telecom Italia central telecommunications research institute ( CSELT ), Basilio Catania, and the Italian Society of Electrotechnics, " Federazione Italiana di Elettrotecnica ", have devoted a Museum to Antonio Meucci, constructing
9163-505: The magneto-electric currents induced in the line by the motion of the distant receiver reed in the neighborhood of its magnet. The battery current was not causing the vibration but was needed only to supply the magnetic field in which the reeds vibrated. Moreover, when Bell heard the rich overtones of the plucked reed, it occurred to him that since the circuit was never broken, all the complex vibrations of speech might be converted into undulating (modulated) currents, which in turn would reproduce
9282-552: The management of telecommunication and broadcasting. The history of broadcasting discusses some debates in relation to balancing conventional communication such as printing and telecommunication such as radio broadcasting. The onset of World War II brought on the first explosion of international broadcasting propaganda. Countries, their governments, insurgents, terrorists, and militiamen have all used telecommunication and broadcasting techniques to promote propaganda. Patriotic propaganda for political movements and colonization started
9401-567: The medium into channels according to frequency is called " frequency-division multiplexing ". Another term for the same concept is " wavelength-division multiplexing ", which is more commonly used in optical communications when multiple transmitters share the same physical medium. Another way of dividing a communications medium into channels is to allocate each sender a recurring segment of time (a "time slot", for example, 20 milliseconds out of each second), and to allow each sender to send messages only within its own time slot. This method of dividing
9520-414: The medium into communication channels is called " time-division multiplexing " ( TDM ), and is used in optical fibre communication. Some radio communication systems use TDM within an allocated FDM channel. Hence, these systems use a hybrid of TDM and FDM. 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
9639-602: The membrane. On 10 March 1876, in a test, between two rooms in a single building, above Palace Theatre , at 109 Court Street , not far from Scollay Square in Boston showed that the telephone worked, but so far, only at a short range. In 1876, Bell became the first to obtain a patent for an "apparatus for transmitting vocal or other sounds telegraphically", after experimenting with many primitive sound transmitters and receivers. Because of illness and other commitments, Bell made little or no telephone improvements or experiments for eight months until after his U.S. patent 174,465
9758-727: The mid-1930s. In 1936, the BBC broadcast propaganda to the Arab World to partly counter similar broadcasts from Italy, which also had colonial interests in North Africa. Modern political debates in telecommunication include the reclassification of broadband Internet service as a telecommunications service (also called net neutrality ), regulation of phone spam , and expanding affordable broadband access. According to data collected by Gartner and Ars Technica sales of main consumer's telecommunication equipment worldwide in millions of units was: In
9877-533: The mid-1960s, thermionic tubes were replaced with the transistor . Thermionic tubes still have some applications for certain high-frequency amplifiers. On 11 September 1940, George Stibitz transmitted problems for his Complex Number Calculator in New York using a teletype and received the computed results back at Dartmouth College in New Hampshire . This configuration of a centralized computer ( mainframe ) with remote dumb terminals remained popular well into
9996-429: The modern era used sounds like coded drumbeats , the blowing of horns , and whistles . Long-distance technologies invented during the 20th and 21st centuries generally use electric power, and include the telegraph , telephone , television , and radio . Early telecommunication networks used metal wires as the medium for transmitting signals. These networks were used for telegraphy and telephony for many decades. In
10115-452: The music store. Telecommunication has also transformed the way people receive their news. A 2006 survey (right table) of slightly more than 3,000 Americans by the non-profit Pew Internet and American Life Project in the United States the majority specified television or radio over newspapers. Telecommunication has had an equally significant impact on advertising. TNS Media Intelligence reported that in 2007, 58% of advertising expenditure in
10234-400: The neighbourhood of 94.5 MHz (megahertz) while another radio station can simultaneously broadcast radio waves at frequencies in the neighbourhood of 96.1 MHz. Each radio station would transmit radio waves over a frequency bandwidth of about 180 kHz (kilohertz), centred at frequencies such as the above, which are called the "carrier frequencies" . Each station in this example
10353-515: The presence or absence of an atmosphere between the two. Radio waves travel through a perfect vacuum just as easily as they travel through air, fog, clouds, or any other kind of gas. The other meaning of the term "channel" in telecommunications is seen in the phrase communications channel , which is a subdivision of a transmission medium so that it can be used to send multiple streams of information simultaneously. For example, one radio station can broadcast radio waves into free space at frequencies in
10472-709: The relationship as causal. Because of the economic benefits of good telecommunication infrastructure, there is increasing worry about the inequitable access to telecommunication services amongst various countries of the world—this is known as the digital divide . A 2003 survey by the International Telecommunication Union (ITU) revealed that roughly a third of countries have fewer than one mobile subscription for every 20 people and one-third of countries have fewer than one land-line telephone subscription for every 20 people. In terms of Internet access, roughly half of all countries have fewer than one out of 20 people with Internet access. From this information, as well as educational data,
10591-714: The sound was "quite faint". She later asked to buy the equipment that was used, but Bell offered to make a model specifically for her. Bell did for the telephone what Henry Ford did for the automobile. Although not the first to experiment with telephonic devices, Bell and the companies founded in his name were the first to develop commercially practical telephones around which a successful business could be built and grow. Bell adopted carbon transmitters similar to Edison's transmitters and adapted telephone exchanges and switching plug boards developed for telegraphy. Watson and other Bell engineers invented numerous other improvements to telephony. Bell succeeded where others failed to assemble
10710-464: The state-owned company on its own. The government instructed TeliaSonera that Cenay Insaat (a Turkish company known for collaborating with the Aliyev regime) and an unknown "local partner" had to undertake the privatization. Shares of the company were transferred to the local partner, which investigative reporting revealed was registered to offshore companies owned by the family of Azerbaijan ruler Ilham Aliyev. In 2018, Fintur Holdings, in which Telia had
10829-511: The telephone including Antonio Meucci , Philipp Reis , Elisha Gray and Alexander Graham Bell , inventors of radio Edwin Armstrong and Lee de Forest , as well as inventors of television like Vladimir K. Zworykin , John Logie Baird and Philo Farnsworth . Since the 1960s, the proliferation of digital technologies has meant that voice communications have gradually been supplemented by data. The physical limitations of metallic media prompted
10948-478: The telephone dates back to the string telephone or lover's telephone that has been known for centuries, comprising two diaphragms connected by a taut string or wire. Sound waves are carried as mechanical vibrations along the string or wire from one diaphragm to the other. The classic example is the tin can telephone , a children's toy made by connecting the two ends of a string to the bottoms of two metal cans, paper cups or similar items. The essential idea of this toy
11067-412: The telephone system were originally advertised with an emphasis on the practical dimensions of the device (such as the ability to conduct business or order home services) as opposed to the social dimensions. It was not until the late 1920s and 1930s that the social dimensions of the device became a prominent theme in telephone advertisements. New promotions started appealing to consumers' emotions, stressing
11186-568: The then circular disc armature of just such another little electro-magnet as this I hold in my hand." Only a few months after receiving U.S. Patent No. 174465 at the beginning of March 1876, Bell conducted three important tests of his new invention and the telephone technology after returning to his parents' home at Melville House (now the Bell Homestead National Historic Site ) for the summer. On March 10, 1876, Bell had used "the instrument" in Boston to call Thomas Watson who
11305-609: The then-newly discovered phenomenon of radio waves , demonstrating, by 1901, that they could be transmitted across the Atlantic Ocean. This was the start of wireless telegraphy by radio. On 17 December 1902, a transmission from the Marconi station in Glace Bay, Nova Scotia, Canada , became the world's first radio message to cross the Atlantic from North America. In 1904, a commercial service
11424-610: The transmitter was difficult to operate, since the relative position of the needle and the contact were critical to the device's operation. Thus, it can be called a "telephone", since it did transmit voice sounds electrically over distance, but was hardly a commercially practical telephone in the modern sense. In 1874, the Reis device was tested by the British company Standard Telephones and Cables (STC). The results also confirmed it could transmit and receive speech with good quality (fidelity), but relatively low intensity. Reis' new invention
11543-490: The voltages and electric currents in them, and free space for communications using visible light , infrared waves, ultraviolet light , and radio waves . Coaxial cable types are classified by RG type or "radio guide", terminology derived from World War II. The various RG designations are used to classify the specific signal transmission applications. This last channel is called the "free space channel". The sending of radio waves from one place to another has nothing to do with
11662-488: The wartime purposes of aircraft and land communication, radio navigation, and radar. Development of stereo FM broadcasting of radio began in the 1930s in the United States and the 1940s in the United Kingdom, displacing AM as the dominant commercial standard in the 1970s. On March 25, 1925, John Logie Baird demonstrated the transmission of moving pictures at the London department store Selfridges . Baird's device relied upon
11781-418: The world's gross domestic product (GDP). Modern telecommunication is founded on a series of key concepts that experienced progressive development and refinement in a period of well over a century: Telecommunication technologies may primarily be divided into wired and wireless methods. Overall, a basic telecommunication system consists of three main parts that are always present in some form or another: In
11900-519: Was articulated in a lecture before the Physical Society of Frankfurt on 26 October 1861, and a description, written by himself for Jahresbericht a month or two later. It created a good deal of scientific excitement in Germany; models of it were sent abroad, to London, Dublin, Tiflis, and other places. It became a subject for popular lectures, and an article for scientific cabinets. Thomas Edison tested
12019-477: Was at the offices of the Walworth Manufacturing Company. Scientific American described the three test calls in their September 9, 1876, article, "The Human Voice Transmitted by Telegraph". Historian Thomas Costain referred to the calls as "the three great tests of the telephone". One Bell Homestead reviewer wrote of them, "No one involved in these early calls could possibly have understood
12138-631: Was awarded the French Volta Prize for his invention and with the money, founded the Volta Laboratory in Washington, where he continued experiments in communication, in medical research, and in techniques for teaching speech to the deaf, working with Helen Keller among others. In 1885 he acquired land in Nova Scotia and established a summer home there where he continued experiments, particularly in
12257-570: Was claimed by many sources as the world's first long-distance call. The final test certainly proved that the telephone could work over long distances. Bell exhibited a working telephone at the Centennial Exhibition in Philadelphia in June 1876, where it attracted the attention of Brazilian emperor Pedro II plus the physicist and engineer Sir William Thomson (who would later be ennobled as
12376-483: Was during the Spanish Armada , when a beacon chain relayed a signal from Plymouth to London . In 1792, Claude Chappe , a French engineer, built the first fixed visual telegraphy system (or semaphore line ) between Lille and Paris. 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
12495-407: Was established to transmit nightly news summaries to subscribing ships, which incorporated them into their onboard newspapers. World War I accelerated the development of radio for military communications . After the war, commercial radio AM broadcasting began in the 1920s and became an important mass medium for entertainment and news. World War II again accelerated the development of radio for
12614-477: Was granted and only as a proof of concept scientific experiment to prove to his own satisfaction that intelligible "articulate speech" (Bell's words) could be electrically transmitted. Because a liquid transmitter was not practical for commercial products, Bell focused on improving the electromagnetic telephone after March 1876 and never used Gray's liquid transmitter in public demonstrations or commercial use. Bell's telephone transmitter (microphone) consisted of
12733-729: Was ill at the time. Some of Meucci's notes purportedly written in 1857 describe the basic principle of electromagnetic voice transmission — or in other words, the telephone. In the 1880s Meucci was credited with the early invention of inductive loading of telephone wires to increase long-distance signals. Serious burns from an accident, a lack of English, and poor business abilities resulted in Meucci's failing to develop his inventions commercially in America. Meucci demonstrated some sort of instrument in 1849 in Havana, Cuba , however, this may have been
12852-495: Was in another room but out of earshot. He said, "Mr. Watson, come here – I want to see you" and Watson soon appeared at his side. In the first test call at a longer distance in Southern Ontario, on August 3, 1876, Alexander Graham's uncle, Professor David Charles Bell, spoke to him from the Brantford telegraph office, reciting lines from Shakespeare 's Hamlet (" To be or not to be.... "). The young inventor, positioned at
12971-462: Was later reconfirmed, according to Article 1.3 of the ITU Radio Regulations , which defined it 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". Homing pigeons have been used throughout history by different cultures. Pigeon post had Persian roots and
13090-657: Was later used by the Romans to aid their military. Frontinus claimed Julius Caesar used pigeons as messengers in his conquest of Gaul . The Greeks also conveyed the names of the victors at the Olympic Games to various cities using homing pigeons. In the early 19th century, the Dutch government used the system in Java and Sumatra . And in 1849, Paul Julius Reuter started a pigeon service to fly stock prices between Aachen and Brussels ,
13209-459: Was later used in similar telecommunication devices. Gauss's and Weber's invention is purported to be the world's first electromagnetic telegraph. In 1840, American Charles Grafton Page passed an electric current through a coil of wire placed between the poles of a horseshoe magnet. He observed that connecting and disconnecting the current caused a ringing sound in the magnet. He called this effect "galvanic music". Innocenzo Manzetti considered
13328-413: Was no contemporary pre-1875 evidence. Meucci's 1871 caveat did not mention any of the telephone features later credited to him by his lawyer, and which were published in that Scientific American Supplement, a major reason for the loss of the 'Bell v. Globe and Meucci' patent infringement court case, which was decided against Globe and Meucci. The Reis telephone was developed from 1857 onwards. Allegedly,
13447-431: Was not quite 13 km (8 miles) long, but the connection was extended a further 93 km (58 miles) to Toronto to allow the use of a battery in its telegraph office . Granted, this was a one-way long-distance call. The first two-way (reciprocal) conversation over a line occurred between Cambridge and Boston (roughly 2.5 miles) on October 9, 1876. During that conversation, Bell was on Kilby Street in Boston and Watson
13566-476: Was of little practical value because it relied on the electrophonic effect requiring users to place the receiver in their mouths to "hear". The first commercial telephone services were set up by the Bell Telephone Company in 1878 and 1879 on both sides of the Atlantic in the cities of New Haven and London. In 1894, Italian inventor Guglielmo Marconi began developing a wireless communication using
13685-570: Was passed by the United States House of Representatives in 2002 that said Meucci did pioneering work on the development of the telephone. The resolution said that "if Meucci had been able to pay the $ 10 fee to maintain the caveat after 1874, no patent could have been issued to Bell". The Meucci resolution by the US Congress was promptly followed by a Canada legislative motion by Canada's 37th Parliament , declaring Alexander Graham Bell as
13804-500: Was patented by Bell on January 30, 1877. The sounds were weak and could only be heard when the ear was close to the earphone/mouthpiece, but they were distinct. In the third of his tests in Southern Ontario, on August 10, 1876, Bell made a call via the telegraph line from the family homestead in Brantford, Ontario , to his assistant located in Paris, Ontario , some 13 kilometers away. This test
13923-458: Was published., but within a year the first telephone exchange was built in Connecticut and the Bell Telephone Company was created in 1877, with Bell the owner of a third of the shares, quickly making him a wealthy man. Organ builder Ernest Skinner reported in his autobiography that Bell offered Boston-area organ builder Hutchings a 50% interest in the company but Hutchings declined. In 1880, Bell
14042-518: Was that a diaphragm can collect voice sounds for reproduction at a distance. One precursor to the development of the electromagnetic telephone originated in 1833 when Carl Friedrich Gauss and Wilhelm Eduard Weber invented an electromagnetic device for the transmission of telegraphic signals at the University of Göttingen , in Lower Saxony, helping to create the fundamental basis for the technology that
14161-440: Was that the device described in the 1871 caveat employed only a single conduction wire, with the telephone's transmitter-receivers being insulated from a 'ground return' path. Meucci studied the principles of electromagnetic voice transmission for many years and was able to realise his dream of transmitting his voice through wires in 1856. He installed a telephone-like device within his house in order to communicate with his wife who
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