1.
Telephone
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A telephone, or phone, is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be heard directly. In 1876, Scottish emigrant Alexander Graham Bell was the first to be granted a United States patent for a device that produced clearly intelligible replication of the human voice and this instrument was further developed by many others. The telephone was the first device in history that people to talk directly with each other across large distances. Telephones rapidly became indispensable to businesses, government, and households, the essential elements of a telephone are a microphone to speak into and an earphone which reproduces the voice in a distant location. Until approximately the 1970s most telephones used a dial, which was superseded by the modern DTMF push-button dial. The receiver and transmitter are usually built into a handset which is held up to the ear, the dial may be located either on the handset, or on a base unit to which the handset is connected. The transmitter converts the sound waves to electrical signals which are sent through the network to the receiving phone. The receiving telephone converts the signals into audible sound in the receiver, telephones permit duplex communication, meaning they allow the people on both ends to talk simultaneously. The first telephones were connected to each other from one customers office or residence to another customers location. Being impractical beyond just a few customers, these systems were replaced by manually operated centrally located switchboards. For greater mobility, various systems were developed for transmission between mobile stations on ships and automobiles in the middle 20th century. Hand-held mobile phone]s was introduced for personal service starting in 1973, by the late 1970s several mobile telephone networks operated around the world. In 1983, the Advanced Mobile Phone System was launched, offering a standardized technology providing portability for users far beyond the residence or office. These analog cellular system evolved into digital networks with better security, greater capacity, better regional coverage, the public switched telephone network, with its hierarchical system of many switching centers, interconnects telephones around the world for communication with each other. With the standardized international numbering system, E.164, each line has an identifying telephone number. Although originally designed for voice communications, convergence has enabled most modern cell phones to have many additional capabilities. Since 1999, the trend for mobile phones is smartphones that integrate all mobile communication, a traditional landline telephone system, also known as plain old telephone service, commonly carries both control and audio signals on the same twisted pair of insulated wires, the telephone line. The control and signaling equipment consists of three components, the ringer, the hookswitch, and a dial, the ringer, or beeper, light or other device, alerts the user to incoming calls
2.
Switchboard operator
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Each pair of plugs was part of a cord circuit with a switch associated that let the operator participate in the call. Each jack had a light above it that lit when the receiver was lifted. Lines from the office were usually arranged along the bottom row. Switchboard operators are required to have very strong communication skills. Before the advent of automatic exchanges, an operators assistance was required for anything other than calling telephones across a party line. Callers spoke to an operator at a Central Office who then connected a cord to the circuit in order to complete the call. Being in complete control of the call, the operator was in a position to listen to private conversations, automatic, or Dial systems were developed in the 1920s to reduce labor costs as usage increased, and to ensure privacy to the customer. As phone systems became more sophisticated, less direct intervention by the operator was necessary to complete calls. As well as the people that were employed by the networks, operators were required at private branch exchanges to answer incoming telephone calls. Today, most large organizations have direct-dial extensions, smaller workplaces may have an automated system which allows callers to enter the extension of the called party, or a receptionist who answers calls and performs operator duties. Operators employed in healthcare settings have other duties, such as entry, greeting patients and visitors, taking messages, triaging. Experienced, well trained operators generally command a higher salary, in January 1878 George Willard Croy became the worlds first telephone operator when he started working for the Boston Telephone Dispatch company. Emma was hired by Alexander Graham Bell, and reportedly, could remember every number in the directory of the New England Telephone Company. Emma Nutt became the first female telephone operator on 1 September 1878 when she started working for the Boston Telephone Dispatch company, more women began to replace men within this sector of the workforce for several reasons. The companies observed that women were generally more courteous to callers, however, a contributing factor to women entering this workforce was because womens labour was cheap in comparison to mens. Specifically, women were paid from one half to one quarter of a mans salary, attendant console Operator assistance Private branch exchange Telephone operator Telephone switchboard Media related to Telephone operators at Wikimedia Commons
3.
India
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India, officially the Republic of India, is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and it is bounded by the Indian Ocean on the south, the Arabian Sea on the southwest, and the Bay of Bengal on the southeast. It shares land borders with Pakistan to the west, China, Nepal, and Bhutan to the northeast, in the Indian Ocean, India is in the vicinity of Sri Lanka and the Maldives. Indias Andaman and Nicobar Islands share a border with Thailand. The Indian subcontinent was home to the urban Indus Valley Civilisation of the 3rd millennium BCE, in the following millennium, the oldest scriptures associated with Hinduism began to be composed. Social stratification, based on caste, emerged in the first millennium BCE, early political consolidations took place under the Maurya and Gupta empires, the later peninsular Middle Kingdoms influenced cultures as far as southeast Asia. In the medieval era, Judaism, Zoroastrianism, Christianity, and Islam arrived, much of the north fell to the Delhi sultanate, the south was united under the Vijayanagara Empire. The economy expanded in the 17th century in the Mughal empire, in the mid-18th century, the subcontinent came under British East India Company rule, and in the mid-19th under British crown rule. A nationalist movement emerged in the late 19th century, which later, under Mahatma Gandhi, was noted for nonviolent resistance, in 2015, the Indian economy was the worlds seventh largest by nominal GDP and third largest by purchasing power parity. Following market-based economic reforms in 1991, India became one of the major economies and is considered a newly industrialised country. However, it continues to face the challenges of poverty, corruption, malnutrition, a nuclear weapons state and regional power, it has the third largest standing army in the world and ranks sixth in military expenditure among nations. India is a constitutional republic governed under a parliamentary system. It is a pluralistic, multilingual and multi-ethnic society and is home to a diversity of wildlife in a variety of protected habitats. The name India is derived from Indus, which originates from the Old Persian word Hindu, the latter term stems from the Sanskrit word Sindhu, which was the historical local appellation for the Indus River. The ancient Greeks referred to the Indians as Indoi, which translates as The people of the Indus, the geographical term Bharat, which is recognised by the Constitution of India as an official name for the country, is used by many Indian languages in its variations. Scholars believe it to be named after the Vedic tribe of Bharatas in the second millennium B. C. E and it is also traditionally associated with the rule of the legendary emperor Bharata. Gaṇarājya is the Sanskrit/Hindi term for republic dating back to the ancient times, hindustan is a Persian name for India dating back to the 3rd century B. C. E. It was introduced into India by the Mughals and widely used since then and its meaning varied, referring to a region that encompassed northern India and Pakistan or India in its entirety
4.
Elizabeth II
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Elizabeth II has been Queen of the United Kingdom, Canada, Australia, and New Zealand since 6 February 1952. Elizabeth was born in London as the eldest child of the Duke and Duchess of York, later King George VI and Queen Elizabeth and her father acceded to the throne on the abdication of his brother Edward VIII in 1936, from which time she was the heir presumptive. She began to undertake duties during the Second World War. Elizabeths many historic visits and meetings include a visit to the Republic of Ireland. She has seen major changes, such as devolution in the United Kingdom, Canadian patriation. She has reigned through various wars and conflicts involving many of her realms and she is the worlds oldest reigning monarch as well as Britains longest-lived. In October 2016, she became the longest currently reigning monarch, in 2017 she became the first British monarch to commemorate a Sapphire Jubilee. Elizabeth has occasionally faced republican sentiments and press criticism of the family, however, support for the monarchy remains high. Elizabeth was born at 02,40 on 21 April 1926, during the reign of her paternal grandfather and her father, Prince Albert, Duke of York, was the second son of the King. Her mother, Elizabeth, Duchess of York, was the youngest daughter of Scottish aristocrat Claude Bowes-Lyon, 14th Earl of Strathmore and she was delivered by Caesarean section at her maternal grandfathers London house,17 Bruton Street, Mayfair. Elizabeths only sibling, Princess Margaret, was born in 1930, the two princesses were educated at home under the supervision of their mother and their governess, Marion Crawford, who was casually known as Crawfie. Lessons concentrated on history, language, literature and music, Crawford published a biography of Elizabeth and Margarets childhood years entitled The Little Princesses in 1950, much to the dismay of the royal family. The book describes Elizabeths love of horses and dogs, her orderliness, others echoed such observations, Winston Churchill described Elizabeth when she was two as a character. She has an air of authority and reflectiveness astonishing in an infant and her cousin Margaret Rhodes described her as a jolly little girl, but fundamentally sensible and well-behaved. During her grandfathers reign, Elizabeth was third in the line of succession to the throne, behind her uncle Edward, Prince of Wales, and her father, the Duke of York. Although her birth generated public interest, she was not expected to become queen, many people believed that he would marry and have children of his own. When her grandfather died in 1936 and her uncle succeeded as Edward VIII, she became second-in-line to the throne, later that year, Edward abdicated, after his proposed marriage to divorced socialite Wallis Simpson provoked a constitutional crisis. Consequently, Elizabeths father became king, and she became heir presumptive, if her parents had had a later son, she would have lost her position as first-in-line, as her brother would have been heir apparent and above her in the line of succession
5.
Republic of Ireland
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Ireland, also known as the Republic of Ireland, is a sovereign state in north-western Europe occupying about five-sixths of the island of Ireland. The capital and largest city is Dublin, which is located on the part of the island. The state shares its land border with Northern Ireland, a part of the United Kingdom. It is otherwise surrounded by the Atlantic Ocean, with the Celtic Sea to the south, Saint Georges Channel to the south-east, and it is a unitary, parliamentary republic. The head of government is the Taoiseach, who is elected by the Dáil and appointed by the President, the state was created as the Irish Free State in 1922 as a result of the Anglo-Irish Treaty. It was officially declared a republic in 1949, following the Republic of Ireland Act 1948, Ireland became a member of the United Nations in December 1955. It joined the European Economic Community, the predecessor of the European Union, after joining the EEC, Ireland enacted a series of liberal economic policies that resulted in rapid economic growth. The country achieved considerable prosperity between the years of 1995 and 2007, which known as the Celtic Tiger period. This was halted by a financial crisis that began in 2008. However, as the Irish economy was the fastest growing in the EU in 2015, Ireland is again quickly ascending league tables comparing wealth and prosperity internationally. For example, in 2015, Ireland was ranked as the joint sixth most developed country in the world by the United Nations Human Development Index and it also performs well in several national performance metrics, including freedom of the press, economic freedom and civil liberties. Ireland is a member of the European Union and is a member of the Council of Europe. The 1922 state, comprising 26 of the 32 counties of Ireland, was styled, the Constitution of Ireland, adopted in 1937, provides that the name of the State is Éire, or, in the English language, Ireland. Section 2 of the Republic of Ireland Act 1948 states, It is hereby declared that the description of the State shall be the Republic of Ireland. The 1948 Act does not name the state as Republic of Ireland, because to have done so would have put it in conflict with the Constitution. The government of the United Kingdom used the name Eire, and, from 1949, Republic of Ireland, for the state, as well as Ireland, Éire or the Republic of Ireland, the state is also referred to as the Republic, Southern Ireland or the South. In an Irish republican context it is referred to as the Free State or the 26 Counties. From the Act of Union on 1 January 1801, until 6 December 1922, during the Great Famine, from 1845 to 1849, the islands population of over 8 million fell by 30%
6.
Telecommunication
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Telecommunication is the transmission of signs, signals, messages, writings, images and sounds or intelligence of any nature by wire, radio, optical or other electromagnetic systems. Telecommunication occurs when the exchange of information between communication participants includes the use of technology and it is transmitted either electrically over physical media, such as cables, or via electromagnetic radiation. Such transmission paths are divided into communication channels which afford the advantages of multiplexing. The term is used in its plural form, telecommunications. Early means of communicating over a distance included visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, other examples of pre-modern long-distance communication included audio messages such as coded drumbeats, lung-blown horns, and loud whistles. Zworykin, John Logie Baird and Philo Farnsworth, the word telecommunication is a compound of the Greek prefix tele, meaning distant, far off, or afar, and the Latin communicare, meaning to share. Its modern use is adapted from the French, because its use was recorded in 1904 by the French engineer. Communication was first used as an English word in the late 14th century, 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 pass a single bit of information. One notable instance of their use was during the Spanish Armada, in 1792, Claude Chappe, a French engineer, built the first fixed visual telegraphy system between Lille and Paris. However semaphore suffered from the need for skilled operators and expensive towers at intervals of ten to thirty kilometres, as a result of competition from the electrical telegraph, the last commercial line was abandoned in 1880. Homing pigeons have occasionally used throughout history by different cultures. Pigeon post is thought to have Persians roots and was used by the Romans to aid their military, frontinus said that 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 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. Sir Charles Wheatstone and Sir William Fothergill Cooke invented the telegraph in 1837. Also, the first commercial electrical telegraph is purported to have constructed by Wheatstone and Cooke. Both inventors viewed their device as an improvement to the electromagnetic telegraph not as a new device, samuel Morse independently developed a version of the electrical telegraph that he unsuccessfully demonstrated on 2 September 1837
7.
History of broadcasting
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The first broadcasting of a radio transmission consisted of Morse code was made from a temporary station set up by Guglielmo Marconi in 1895. This followed on from pioneering work in the field by Alessandro Volta, André-Marie Ampère, Georg Ohm, James Clerk Maxwell, the broadcasting of music and talk via radio started experimentally around 1905-1906, and commercially around 1920 to 1923. VHF stations started 30 to 35 years later, when people started broadcasting television the first movie that was shown was Batman curse of the green pearl it was 10 minutes long. In Britain this system was known as Electrophone, and was available as early as 1895 or 1899, in Hungary, it was called Telefon Hírmondó, and in France, Théâtrophone ). The Wikipedia Telefon Hírmondó page includes a 1907 program guide which looks similar to the types of schedules used by many broadcasting stations some 20 or 30 years later. By the 1950s, virtually every country had a broadcasting system, today, most countries have evolved into a dual system, including the UK. By 1955, practically every family in North America and Western Europe, a dramatic change came in the 1960s with the introduction of small inexpensive portable transistor radio, the greatly expanded ownership and usage. Access became practically universal across the world, Australia developed its own system, through its own engineers, manufacturers, retailers, newspapers, entertainment services, and news agencies. The government set up the first radio system, and business interests marginalized the hobbyists, the Labor Party was especially interested in radio because it allowed them to bypass the newspapers, which were mostly controlled by the opposition. Both parties agreed on the need for a system, and in 1932 set up the Australian Broadcasting Commission. The first commercial broadcasters, originally known as B class stations, were on the air as early as 1925, the number of stations remained relatively dormant throughout World War II and in the post-war era. The broadcasting system was deregulated in 1992, except that there were limits on foreign ownership. By 2000,99 percent of Australians owned at least one television set, Australian radio hams can be traced to the early 1900s. The 1905 Wireless Telegraphy Act whilst acknowledging the existence of wireless telgraphy, in 1906, the first official Morse code transmission in Australia was by the Marconi Company between Queenscliff, Victoria and Devonport, Tasmania. The first broadcast of music was made during a demonstration on 13 August 1919 by Ernest Fisk of AWA – Amalgamated Wireless, a number of amateurs commenced broadcasting music in 1920 and 1921. 2CM was run by Charles MacLuran who started the station in 1921 with regular Sunday evening broadcasts from the Wentworth Hotel, 2CM is often regarded as Australias first, regular, non-official station. It was not until November 1923 when the government finally gave its approval for a number of officially recognised medium wave stations, all stations operated under a unique Sealed Set system under which each set was sealed to the frequency of one station. Part of the price of the set went to the government via the Postmaster-Generals Department, apart from extremely limited advertising, this was the broadcasters only source of income
8.
Electrical telegraph
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An electrical telegraph is a telegraph that uses electrical signals, usually conveyed via dedicated telecommunication lines or radio. From early studies of electricity, electrical phenomena were known to travel with great speed, in 1753 an anonymous writer in the Scots Magazine suggested an electrostatic telegraph. In 1774 Georges-Louis Le Sage realised an early electric telegraph, the telegraph had a separate wire for each of the 26 letters of the alphabet and its range was only between two rooms of his home. In 1800 Alessandro Volta invented the voltaic pile, allowing for a current of electricity for experimentation. Both their designs employed multiple wires to represent almost all Latin letters, thus, messages could be conveyed electrically up to a few kilometers, with each of the telegraph receivers wires immersed in a separate glass tube of acid. The telegraph receivers operator would watch the bubbles and could record the transmitted message. This is in contrast to later telegraphs that used a single wire, hans Christian Ørsted discovered in 1820 that an electric current produces a magnetic field which will deflect a compass needle. In the same year Johann Schweigger invented the galvanometer, with a coil of wire around a compass, in 1824, Peter Barlow said that such a system only worked to a distance of about 200 feet, and so was impractical. In 1825 William Sturgeon invented the electromagnet, with a winding of uninsulated wire on a piece of varnished iron. During his tenure at The Albany Academy from 1826 to 1832, in 1835 Joseph Henry and Edward Davy invented the critical electrical relay. Davys relay used a needle which dipped into a mercury contact when an electric current passed through the surrounding coil. This allowed a weak current to switch a larger current to operate a powerful local electromagnet over very long distances, Davy demonstrated his telegraph system in Regents Park in 1837 and was granted a patent on 4 July 1838. He also developed an electric relay, the first working telegraph was built by the English inventor Francis Ronalds in 1816 and used static electricity. At the family home on Hammersmith Mall, he set up a subterranean system in a 175 yard long trench as well as an eight mile long overhead telegraph. The lines were connected at both ends to revolving dials marked with the letters of the alphabet and electrical impulses sent along the wire were used to transmit messages, offering his invention to the Admiralty in July 1816, it was rejected as “wholly unnecessary”. Elements of Ronalds’ design were utilised in the subsequent commercialisation of the telegraph over 20 years later, the telegraph invented by Baron Schilling von Canstatt in 1832 had a transmitting device which consisted of a keyboard with 16 black-and-white keys. These served for switching the electric current, the receiving instrument consisted of six galvanometers with magnetic needles, suspended from silk threads. Both stations of Shillings telegraph were connected by eight wires, six were connected with the galvanometers, one served for the return current, when at the starting station the operator pressed a key, the corresponding pointer was deflected at the receiving station
9.
Fax
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Fax, sometimes called telecopying or telefax, is the telephonic transmission of scanned printed material, normally to a telephone number connected to a printer or other output device. The receiving fax machine interprets the tones and reconstructs the image, early systems used direct conversions of image darkness to audio tone in a continuous or analog manner. Since the 1980s, most machines modulate the audio frequencies using a digital representation of the page which is compressed to quickly transmit areas which are all-white or all-black. Scottish inventor Alexander Bain worked on chemical mechanical fax type devices and he received British patent 9745 on May 27,1843 for his Electric Printing Telegraph. Frederick Bakewell made several improvements on Bains design and demonstrated a telefax machine, the Pantelegraph was invented by the Italian physicist Giovanni Caselli. He introduced the first commercial service between Paris and Lyon in 1865, some 11 years before the invention of the telephone. In 1880, English inventor Shelford Bidwell constructed the scanning phototelegraph that was the first telefax machine to scan any two-dimensional original, previously, photographs had been sent over the radio using this process. The Western Union Deskfax fax machine, announced in 1948, was a machine that fit comfortably on a desktop. As a designer for the Radio Corporation of America, in 1924, Richard H. Ranger invented the wireless photoradiogram, or transoceanic radio facsimile, the forerunner of today’s fax machines. A photograph of President Calvin Coolidge sent from New York to London on November 29,1924 became the first photo picture reproduced by transoceanic radio facsimile, commercial use of Ranger’s product began two years later. Also in 1924, Herbert E. Ives of AT&T Corporation transmitted and reconstructed the first color facsimile, around 1952 or so, Finch Facsimile, a highly developed machine, was described in detail in a book, it was never manufactured in quantity. By the late 1940s, radiofax receivers were sufficiently miniaturized to be fitted beneath the dashboard of Western Unions Telecar telegram delivery vehicles, in the 1960s, the United States Army transmitted the first photograph via satellite facsimile to Puerto Rico from the Deal Test Site using the Courier satellite. Radio fax is still in limited use today for transmitting weather charts, in 1964, Xerox Corporation introduced what many consider to be the first commercialized version of the modern fax machine, under the name or Long Distance Xerography. This model was superseded two years later with a unit that would set the standard for fax machines for years to come. Up until this point facsimile machines were expensive and hard to operate. In 1966, Xerox released the Magnafax Telecopiers, a smaller and this unit was far easier to operate and could be connected to any standard telephone line. This machine was capable of transmitting a letter-sized document in about six minutes, the first sub-minute, digital fax machine was developed by Dacom, which built on digital data compression technology originally developed at Lockheed for satellite communication. By the late 1970s, many companies around the world, entered the fax market, very shortly after a new wave of more compact, faster and efficient fax machines would hit the market
10.
Heliograph
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A heliograph is a wireless solar telegraph that signals by flashes of sunlight reflected by a mirror. The flashes are produced by momentarily pivoting the mirror, or by interrupting the beam with a shutter, the heliograph was a simple but effective instrument for instantaneous optical communication over long distances during the late 19th and early 20th century. Its main uses were military, survey and forest protection work, heliographs were standard issue in the British and Australian armies until the 1960s, and were used by the Pakistani army as late as 1975. Most heliographs were variants of the British Army Mance Mark V version and it used a mirror with a small unsilvered spot in the centre. The sender aligned the heliograph to the target by looking at the target in the mirror. Keeping his head still, he adjusted the aiming rod so its cross wires bisected the target. This indicated that the sunbeam was pointing at the target, the flashes were produced by a keying mechanism that tilted the mirror up a few degrees at the push of a lever at the back of the instrument. If the sun was in front of the sender, its rays were reflected directly from this mirror to the receiving station. If the sun was behind the sender, the rod was replaced by a second mirror, to capture the sunlight from the main mirror. The U. S. Signal Corps heliograph mirror did not tilt and this type produced flashes by a shutter mounted on a second tripod. The heliograph had some great advantages, however, anyone in the beam with the correct knowledge could intercept signals without being detected. In the Boer War, where both sides used heliographs, tubes were used to decrease the dispersion of the beam.5 degrees to 15 degrees. The distance that signals could be seen depended on the clarity of the sky. A clear line of sight was required, and since the Earths surface is curved, under ordinary conditions, a flash could be seen 30 miles with the naked eye, and much farther with a telescope. The maximum range was considered to be 10 miles for each inch of mirror diameter, mirrors ranged from 1.5 inches to 12 inches or more. The record distance was established by a detachment of U. S, the German professor Carl Friedrich Gauss of the University of Göttingen developed and used a predecessor of the heliograph in 1821. His device directed a beam of sunlight to a distant station to be used as a marker for geodetic survey work. Similarly, the story that a shield was used as a heliograph at the Battle of Marathon is a modern myth, what Herodotus did write was that someone was accused of having arranged to hold up a shield as a signal
11.
History of the Internet
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The history of the Internet begins with the development of electronic computers in the 1950s. Initial concepts of packet networking originated in several science laboratories in the United States, United Kingdom. The US Department of Defense awarded contracts as early as the 1960s for packet network systems, including the development of the ARPANET. Packet switching networks such as ARPANET, NPL network, CYCLADES, Merit Network, Tymnet, Donald Davies first designed a packet-switched network at the National Physics Laboratory in the UK, which became a testbed for UK research for almost two decades. The ARPANET project led to the development of protocols for internetworking, Access to the ARPANET was expanded in 1981 when the National Science Foundation funded the Computer Science Network. In 1982, the Internet protocol suite was introduced as the networking protocol on the ARPANET. Commercial Internet service providers began to emerge in the very late 1980s, the ARPANET was decommissioned in 1990. The research and education community continues to develop and use advanced networks such as NSFs very high speed Backbone Network Service, Internet2, increasing amounts of data are transmitted at higher and higher speeds over fiber optic networks operating at 1-Gbit/s, 10-Gbit/s, or more. Today the Internet continues to grow, driven by ever greater amounts of information, commerce, entertainment. Such communication systems were limited to point to point communication between two end devices. Telegraph systems and telex machines can be considered precursors of this kind of communication. The Telegraph in the late 19th century was the first fully digital communication system, fundamental theoretical work in data transmission and information theory was developed by Claude Shannon, Harry Nyquist, and Ralph Hartley in the early 20th century. Early computers had a processing unit and remote terminals. As the technology evolved, new systems were devised to allow communication over longer distances or with higher speed that were necessary for the computer model. These technologies made it possible to exchange data between remote computers, however, the point-to-point communication model was limited, as it did not allow for direct communication between any two arbitrary systems, a physical link was necessary. The technology was considered unsafe for strategic and military use because there were no alternative paths for the communication in case of an enemy attack. With limited exceptions, the earliest computers were connected directly to terminals used by individual users, such networks became known as local-area networks. Networking beyond this scope, known as wide-area networks, emerged during the 1950s, J. C. R. Licklider, Vice President at Bolt Beranek and Newman, Inc
12.
History of mobile phones
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The history of mobile phones, covers mobile communication devices which connect wirelessly to the public switched telephone network. While the transmission of speech by radio has a history, the first models that were wireless, mobile. The first such devices were barely portable compared to todays compact hand-held devices, before the devices that are now referred as mobile phones existed, there were some precursors. In 1908 a Professor Albert Jahnke and the Oakland Transcontinental Aerial Telephone and they were accused of fraud and the charge was then dropped, but they do not seem to have proceeded with production. Beginning in 1918 the German railroad system tested wireless telephony on military trains between Berlin and Zossen, in 1924, public trials started with telephone connection on trains between Berlin and Hamburg. In 1925, the company Zugtelephonie A. G, the portrayal of a Utopia of mobile phone in literature dates back to the year 1931. It is found in Erich Kästners childrens book The 35th of May, or Conrads Ride to the South Seas, hand-held radio transceivers have been available since the 1940s. Mobile telephones for automobiles became available from some companies in the 1940s. Early devices were bulky, consumed high power, and the network supported only a few simultaneous conversations, modern cellular networks allow automatic and pervasive use of mobile phones for voice and data communications. Shortly after, AT&T offered Mobile Telephone Service, a wide range of mostly incompatible mobile telephone services offered limited coverage area and only a few available channels in urban areas. One of the earliest fictional descriptions of a phone was the 1948 science fiction novel Space Cadet by Robert Heinlein. The protagonist, who has just traveled to Colorado from his home in Des Moines, receives a call from his father on a pocket telephone. Before going to space he decides to ship the telephone home since it was limited by its range to the neighborhood of an earth-side relay office. Ten years later, an essay by Arthur C. Clarke envisioned a personal transceiver, so small and he wrote, the time will come when we will be able to call a person anywhere on Earth merely by dialing a number. Such a device would also, in Clarkes vision, include means for global positioning so that no one need ever again be lost, later, in Profiles of the Future, he predicted the advent of such a device taking place in the mid-1980s. U. S. TV series Get Smart depicted spy gadgets with mobile telephones concealed in random objects, in the USSR, Leonid Kupriyanovich, an engineer from Moscow, in 1957-1961 developed and presented a number of experimental models of handheld mobile phones. The weight of one model, presented in 1961, was only 70 g, however, in the USSR the decision at first to develop the system of the automobile Altai phone was made. In 1965, Bulgarian company Radioelektronika presented on the Inforga-65 international exhibition in Moscow the mobile automatic phone combined with a base station, solutions of this phone were based on a system developed by Leonid Kupriyanovich
