138-582: COMSAT ( Communications Satellite Corporation ) is a global telecommunications company based in the United States . By 2007, it had branches in Brazil , Argentina , Colombia , Mexico , Peru , Venezuela and several other countries in the Americas . Although it operated many kinds of data communication technologies, it is best known for its satellite communication services . COMSAT Corporation
276-412: 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
414-411: 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
552-571: A Tuath . The North Sea has provided waterway access for commerce and conquest. Many areas have access to the North Sea because of its long coastline and the European rivers that empty it. There is little documentary evidence concerning the North Sea before the Roman conquest of Britain in 43 CE, however, archaeological evidence reveals the diffusion of cultures and technologies from across or along
690-411: 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
828-438: 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
966-738: A challenge to their dominance of the North Sea until the 20th century. Tensions in the North Sea were again heightened in 1904 by the Dogger Bank incident . During the Russo-Japanese War , several ships of the Russian Baltic Fleet, which was on its way to the Far East, mistook British fishing boats for Japanese ships and fired on them, and then upon each other, near the Dogger Bank, nearly causing Britain to enter
1104-441: 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
1242-495: 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
1380-406: 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
1518-450: 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
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#17327909522411656-838: 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
1794-437: 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
1932-567: A provider of network services to the South American corporate market) from Lockheed Martin Corporation in the 2nd quarter of 2002. On 11 May 2004, Lockheed Martin announced that Intelsat, Ltd. would acquire Lockheed Martin's COMSAT General business for US$ 90 million. At that time, COMSAT General provided satellite-centric telecommunications services and equipment, concentrating on international fixed and mobile satellite systems. In
2070-491: 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
2208-523: A rich source of energy resources, including wind and wave power . The North Sea has featured prominently in geopolitical and military affairs, particularly in Northern Europe , from the Middle Ages to the modern era. It was also important globally through the power northern Europeans projected worldwide during much of the Middle Ages and into the modern era. The North Sea was the centre of
2346-415: 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
2484-442: A single medium to transmit several concurrent communication sessions . Several methods of long-distance communication before 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
2622-611: A six-person founding board of directors appointed by President John F. Kennedy , including: Phil Graham who served as Chairman (until his resignation in January 1963); Leo D. Welch, Joseph V. Charyk , David M. Kennedy , George Killion , Leonard H. Marks , and Bruce Sundlun . In August 1964, COMSAT helped create the International Telecommunications Satellite Consortium ( Intelsat ), an international satellite organization with
2760-411: 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
2898-717: A vast merchant marine, a large fishing fleet, powerful navy, and sophisticated financial markets made the Dutch the ascendant power in the North Sea, to be challenged by an ambitious England. This rivalry led to the first three Anglo-Dutch Wars between 1652 and 1673, which ended with Dutch victories. After the Glorious Revolution in 1688, the Dutch prince William ascended to the English throne. With unified leadership, commercial, military, and political power began to shift from Amsterdam to London. The British did not face
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#17327909522413036-412: 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
3174-536: A volume of 54,000 cubic kilometres (13,000 cu mi). Around the edges of the North Sea are sizeable islands and archipelagos , including Shetland , Orkney , and the Frisian Islands . The North Sea receives freshwater from a number of European continental watersheds, as well as the British Isles . A large part of the European drainage basin empties into the North Sea, including water from
3312-565: Is 17 °C (63 °F) in the summer and 6 °C (43 °F) in the winter. The average temperatures have been trending higher since 1988, which has been attributed to climate change . Air temperatures in January range on average between 0 and 4 °C (32 and 39 °F) and in July between 13 and 18 °C (55 and 64 °F). The winter months see frequent gales and storms. The salinity averages between 34 and 35 grams per litre (129 and 132 g/US gal) of water. The salinity has
3450-466: Is Nancy Laurie's sister. Liberty retained only a 6.5% stake of the sports franchises. As part of the deal, Kroenke placed the teams into a trust that would ensure the teams will stay in Denver until at least 2025. After the deal, Kroenke organized his sports assets under Kroenke Sports Enterprises . Telecommunications Telecommunication , often used in its plural form or abbreviated as telecom ,
3588-466: Is a series of asymmetrical trenches between 20 and 30 kilometres (12 and 19 mi) long, one and two kilometres (0.6 and 1.2 mi) wide and up to 230 metres (750 ft) deep. Other areas which are less deep are Cleaver Bank , Fisher Bank and Noordhinder Bank . The International Hydrographic Organization defines the limits of the North Sea as follows: On the Southwest. A line joining
3726-581: 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
3864-526: Is also home to marine mammals. Common seals , grey seals , and harbour porpoises can be found along the coasts, at marine installations, and on islands. The very northern North Sea islands such as the Shetland Islands are occasionally home to a larger variety of pinnipeds including bearded , harp , hooded and ringed seals , and even walrus . North Sea cetaceans include various porpoise , dolphin and whale species. Plant species in
4002-780: Is bounded by the Orkney Islands and east coast of Great Britain to the west and the northern and central European mainland to the east and south, including Norway , Denmark , Germany , the Netherlands , Belgium , and France . In the southwest, beyond the Straits of Dover , the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via
4140-671: 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
4278-451: 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
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4416-434: 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
4554-794: 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
4692-481: 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
4830-699: Is recorded to have killed more than 100,000 people. In 1362, the Second Marcellus Flood , also known as the Grote Manndrenke , hit the entire southern coast of the North Sea. Chronicles of the time again record more than 100,000 deaths, large parts of the coast were lost permanently to the sea, including the now legendary lost city of Rungholt . In the 20th century, the North Sea flood of 1953 flooded several nations' coasts and cost more than 2,000 lives. 315 citizens of Hamburg died in
4968-609: 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
5106-448: 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
5244-536: Is the Norwegian trench , which extends parallel to the Norwegian shoreline from Oslo to an area north of Bergen . It is between 20 and 30 kilometres (12 and 19 mi) wide and has a maximum depth of 725 metres (2,379 ft). The Dogger Bank , a vast moraine , or accumulation of unconsolidated glacial debris, rises to a mere 15 to 30 m (50 to 100 ft) below the surface. This feature has produced
5382-449: 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
5520-569: 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 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
5658-538: The Atlantic Ocean through the English Channel in the south and the Norwegian Sea in the north. It is more than 970 kilometres (600 mi) long and 580 kilometres (360 mi) wide, covering 570,000 square kilometres (220,000 sq mi). It hosts key north European shipping lanes and is a major fishery . The coast is a popular destination for recreation and tourism in bordering countries, and
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5796-518: The Baltic Sea . The largest and most important rivers flowing into the North Sea are the Elbe and the Rhine – Meuse . Around 185 million people live in the catchment area of the rivers discharging into the North Sea encompassing some highly industrialized areas. For the most part, the sea lies on the European continental shelf with a mean depth of 90 metres (300 ft). The only exception
5934-525: The Battle of Heligoland Bight , the Battle of the Dogger Bank , and the Battle of Jutland . World War I also brought the first extensive use of submarine warfare , and a number of submarine actions occurred in the North Sea. The Second World War also saw action in the North Sea, though it was restricted more to aircraft reconnaissance and action by fighter/bomber aircraft, submarines and smaller vessels such as minesweepers and torpedo boats . After
6072-662: The Colorado Avalanche . The Nuggets' purchase was one of professional sports' first attempts to introduce African-Americans into ownership groups (it included Peter Bynoe , a Chicago lawyer, and business partner Bertram Lee , who held a combined 37.5% interest). COMSAT bought out its other shareholders in 1992. After buying the Avalanche, COMSAT organized its Denver sports franchises under a separate subsidiary, Ascent Entertainment Group Inc. , which went public in 1995, with COMSAT retaining an 80% controlling interest and
6210-528: The English Channel was triggered by the earthquake, which in turn caused a tsunami. The tsunami triggered by the 1755 Lisbon earthquake reached Holland, although the waves had lost their destructive power. The largest earthquake ever recorded in the United Kingdom was the 1931 Dogger Bank earthquake , which measured 6.1 on the Richter magnitude scale and caused a small tsunami that flooded parts of
6348-517: The Last Glacial Maximum when the sea began to flood the European continental shelf. In 2006 a bone fragment was found while drilling for oil in the North Sea. Analysis indicated that it was a Plateosaurus from 199 to 216 million years ago. This was the deepest dinosaur fossil ever found and the first find for Norway. Copepods and other zooplankton are plentiful in the North Sea. These tiny organisms are crucial elements of
6486-965: The Latin names Mare Germanicum and Oceanus Germanicus , and these persisted in use until the First World War. Other common names in use for long periods were the Latin terms Mare Frisicum , as well as the English equivalent, "Frisian Sea". The modern names of the sea in the other local languages are: Danish : Vesterhavet , lit. 'West Sea' [ˈvestɐˌhɛˀvð̩] or Nordsøen [ˈnoɐ̯ˌsøˀn̩] , Dutch : Noordzee , Dutch Low Saxon : Noordzee , French : Mer du Nord , West Frisian : Noardsee , German : Nordsee , Low German : Noordsee , North Frisian : Weestsiie , lit. 'West Sea', Swedish : Nordsjön , Bokmål : Nordsjøen [ˈnûːrˌʂøːn] , Nynorsk : Nordsjøen , Scots : North Sea and Scottish Gaelic : An Cuan
6624-773: 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
6762-472: The North Sea flood of 1962 . Though rare, the North Sea has been the site of a number of historically documented tsunamis . The Storegga Slides were a series of underwater landslides, in which a piece of the Norwegian continental shelf slid into the Norwegian Sea. The immense landslips occurred between 8150 BCE and 6000 BCE, and caused a tsunami up to 20 metres (66 ft) high that swept through
6900-1016: The Phare de Walde (Walde Lighthouse, in France, 50°59'37"N, 1°54'53"E) and Leathercoat Point (England, 51°10'01.4"N 1°24'07.8"). northeast of Dover. On the Northwest. From Dunnet Head (58°40'20"N, 3°22'30"W) in Scotland to Tor Ness (58°47'N) in the Island of Hoy , thence through this island to the Kame of Hoy (58°55'N) on to Breck Ness on Mainland (58°58'N) through this island to Costa Head (3°14'W) and Inga Ness (59'17'N) in Westray through Westray, to Bow Head, across to Mull Head (North point of Papa Westray ) and on to Seal Skerry (North point of North Ronaldsay ) and thence to Horse Island (South point of
7038-826: The Shetland Islands). On the North. From the North point (Fethaland Point) of the Mainland of the Shetland Islands, across to Graveland Ness (60°39'N) in the Island of Yell , through Yell to Gloup Ness (1°04'W) and across to Spoo Ness (60°45'N) in Unst island, through Unst to Herma Ness (60°51'N), on to the SW point of the Rumblings and to Muckle Flugga ( 60°51′N 0°53′W / 60.850°N 0.883°W / 60.850; -0.883 ) all these being included in
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#17327909522417176-608: The Skagerrak and Kattegat , narrow straits that separate Denmark from Norway and Sweden respectively. In the north it is bordered by the Shetland Islands , and connects with the Norwegian Sea , which is a marginal sea in the Arctic Ocean . The North Sea is more than 970 kilometres (600 mi) long and 580 kilometres (360 mi) wide, with an area of 750,000 square kilometres (290,000 sq mi) and
7314-755: The United States Navy and other maritime customers, and Comstar, a domestic satellite system. To separate these activities from its Intelsat business as required by the Federal Communications Commission, a subsidiary company named Comsat General was formed. In 1982, the Marisat satellites, along with three Marisat Earth stations (two in the US — Southbury , Connecticut , and Santa Paula , California — and one in Japan ) formed
7452-627: The Vikings' rise . The Hanseatic League , the Dutch Republic , and the British each sought to gain command of the North Sea and access to the world's markets and resources. As Germany's only outlet to the ocean, the North Sea was strategically important through both world wars. The coast has diverse geology and geography. In the north, deep fjords and sheer cliffs mark much of its Norwegian and Scottish coastlines respectively, whereas in
7590-463: The food chain supporting many species of fish. Over 230 species of fish live in the North Sea. Cod , haddock , whiting , saithe , plaice , sole , mackerel , herring , pouting , sprat , and sandeel are all very common and are fished commercially. Due to the various depths of the North Sea trenches and differences in salinity, temperature, and water movement, some fish such as blue-mouth redfish and rabbitfish reside only in small areas of
7728-535: The littoral is low and marshy. The east coast and south-east of the North Sea ( Wadden Sea ) have coastlines that are mainly sandy and straight owing to longshore drift , particularly along Belgium and Denmark. The southern coastal areas were originally flood plains and swampy land. In areas especially vulnerable to storm surges, people settled behind elevated levees and on natural areas of high ground such as spits and geestland . As early as 500 BC, people were constructing artificial dwelling hills higher than
7866-440: 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
8004-741: The 13th century the Hanseatic League , though centred on the Baltic Sea , started to control most of the trade through important members and outposts on the North Sea. The League lost its dominance in the 16th century, as neighbouring states took control of former Hanseatic cities and outposts. Their internal conflict prevented effective cooperation and defence. As the League lost control of its maritime cities, new trade routes emerged that provided Europe with Asian, American, and African goods. The 17th century Dutch Golden Age saw Dutch maritime power at its zenith. Important overseas colonies,
8142-705: 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
8280-497: 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
8418-778: The 2nd quarter of 2007, BT Group of the United Kingdom announced the acquisition of COMSAT International from CIH, and Lockheed Martin announced the sale of its remaining 20% interest in COMSAT International. COMSAT operated the Denver Nuggets of the National Basketball Association from 1989 to 2000 [1] , and added to its sports portfolio by purchasing the Quebec Nordiques in 1995 and moving them to Denver as
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#17327909522418556-411: The Avalanche and Nuggets. After almost two years, Ascent sold the Avalanche and Nuggets to Walmart heirs Bill and Nancy Laurie for US$ 400 million. However, a group of Ascent shareholders sued, claiming that the sale price was several million dollars too low. Ascent then agreed to sell the Avalanche and Nuggets to Denver banking tycoon Donald Sturm for US$ 461 million. However, the deal unraveled when
8694-583: The British coast. Shallow epicontinental seas like the current North Sea have since long existed on the European continental shelf . The rifting that formed the northern part of the Atlantic Ocean during the Jurassic and Cretaceous periods, from about 150 million years ago , caused tectonic uplift in the British Isles. Since then, a shallow sea has almost continuously existed between
8832-466: 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
8970-744: 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
9108-508: The Middle Ages through the 15th century, the northern European coastal ports exported domestic goods, dyes, linen, salt, metal goods and wine. The Scandinavian and Baltic areas shipped grain, fish, naval necessities, and timber. In turn, the North Sea countries imported high-grade cloths, spices, and fruits from the Mediterranean region. Commerce during this era was mainly conducted by maritime trade due to underdeveloped roadways. In
9246-426: The Netherlands. The North Sea Floods of 1953 and 1962 were the impetus for further raising of the dikes as well as the shortening of the coast line so as to present as little surface area as possible to the punishment of the sea and the storms. Currently, 27% of the Netherlands is below sea level protected by dikes, dunes, and beach flats. Coastal management today consists of several levels. The dike slope reduces
9384-683: The North Sea are home to nature reserves including the Ythan Estuary , Fowlsheugh Nature Preserve, and Farne Islands in the UK and the Wadden Sea National Parks in Denmark, Germany and the Netherlands. These locations provide breeding habitat for dozens of bird species. Tens of millions of birds make use of the North Sea for breeding, feeding, or migratory stopovers every year. Populations of black-legged kittiwakes , Atlantic puffins , northern gannets , northern fulmars , and species of petrels , seaducks , loons (divers), cormorants , gulls , auks , and terns , and many other seabirds make these coasts popular for birdwatching . The North Sea
9522-516: The North Sea area; thence up the meridian of 0°53' West to the parallel of 61°00' North and eastward along this parallel to the coast of Norway, the whole of Viking Bank is thus included in the North Sea. On the East. The Western limit of the Skagerrak [A line joining Hanstholm ( 57°07′N 8°36′E / 57.117°N 8.600°E / 57.117; 8.600 ) and the Naze ( Lindesnes , 58°N 7°E / 58°N 7°E / 58; 7 )]. The average temperature
9660-402: The North Sea during the Migration Period . They made successive invasions of the island from what is now the Netherlands, Denmark, and Germany. The Viking Age began in 793 with the attack on Lindisfarne ; for the next quarter-millennium, the Vikings ruled the North Sea. In their superior longships , they raided, traded, and established colonies and outposts along the coasts of the sea. From
9798-554: The North Sea include species of wrack , among them bladder wrack , knotted wrack , and serrated wrack. Algae , macroalgal, and kelp , such as oarweed and laminaria hyperboria, and species of maerl are found as well. Eelgrass , formerly common in the entirety of the Wadden Sea, was nearly wiped out in the 20th century by a disease. Similarly, sea grass used to coat huge tracts of ocean floor, but have been damaged by trawling and dredging have diminished its habitat and prevented its return. Invasive Japanese seaweed has spread along
9936-500: The North Sea to Great Britain and Scandinavia and reliance by some prehistoric cultures on fishing, whaling, and seaborne trade on the North Sea. The Romans established organised ports in Britain, which increased shipping and began sustained trade the diffusion of cultures and technologies from across or along the North Sea to Great Britain and Scandinavia and reliance by some prehistoric cultures on fishing, whaling, and seaborne trade on
10074-416: The North Sea until the 20th century, when numbers declined due to overfishing . Other factors like the introduction of non-indigenous species , industrial and agricultural pollution , trawling and dredging , human-induced eutrophication , construction on coastal breeding and feeding grounds, sand and gravel extraction, offshore construction , and heavy shipping traffic have also contributed to
10212-590: The North Sea, having the greatest effect on Scotland and the Faeroe Islands . The Dover Straits earthquake of 1580 is among the first recorded earthquakes in the North Sea measuring between 5.6 and 5.9 on the Richter scale. This event caused extensive damage in Calais both through its tremors and possibly triggered a tsunami , though this has never been confirmed. The theory is a vast underwater landslide in
10350-453: The North Sea. Crustaceans are also commonly found throughout the sea. Norway lobster , deep-water prawns , and brown shrimp are all commercially fished, but other species of lobster , shrimp , oyster , mussels and clams all live in the North Sea. Recently non-indigenous species have become established including the Pacific oyster and Atlantic jackknife clam . The coasts of
10488-517: The North Sea. The Romans established organised ports in Britain, which increased shipping and began sustained trade and many Scandinavian tribes participated in raids and wars against the Romans and Roman coinage and manufacturing were important trade goods. When the Romans abandoned Britain in 410, the Germanic Angles , Frisians , Saxons , and Jutes began the next great migration across
10626-500: The North Sea. The wave continues to travel northward in the Atlantic Ocean, and once past the northern tip of Great Britain, the Kelvin wave turns east and south and once again enters the North Sea. The eastern and western coasts of the North Sea are jagged, formed by glaciers during the ice ages . The coastlines along the southernmost part are covered with the remains of deposited glacial sediment. The Norwegian mountains plunge into
10764-558: The Orkney Islands through the mid-16th century, as both Sable Island and Orkney Islands lay within their normal range. Grey whales also resided in the North Sea but were driven to extinction in the Atlantic in the 17th century Other species have dramatically declined in population, though they are still found. North Atlantic right whales , sturgeon , shad , rays , skates , salmon , and other species were common in
10902-533: The U.S. owner, and the largest shareholder, in both the INTELSAT and INMARSAT systems. INMARSAT was fully privatized on April 15, 1999. Comsat serves as the U.S. Signatory to INTELSAT, and will continue in that role until INTELSAT's expected privatization in 2001 at which point it will become a shareholder. On 27 March 2001, LMGT announced the sale of the COMSAT mobile communications unit, which had been aligned with
11040-442: 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
11178-797: 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
11316-495: 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. North Sea Download coordinates as: The North Sea lies between Great Britain , Denmark , Norway , Germany , the Netherlands , Belgium and France . An epeiric sea on the European continental shelf , it connects to
11454-459: The city of Denver insisted that Sturm promise to keep the Nuggets and Avalanche in Denver for at least 25 years before it transferred the parcel of land on which Pepsi Center stood. Sturm had bought the teams in his own name, and city officials wanted to protect taxpayers in case Sturm either died or sold the teams before the 25 years ran out. While Sturm was willing to make a long-term commitment to
11592-462: The city, he wasn't willing to be held responsible if he died or sold the teams. After negotiations fell apart, Liberty bought all Ascent, but kept the Nuggets and Avalanche on the market. Finally, in July 2000, the Avalanche, Nuggets and Pepsi Center were bought by real estate entrepreneur Stan Kroenke in a US$ 450 million deal. Kroenke is the brother-in-law of the Lauries; his wife Ann Walton Kroenke
11730-611: The coasts of the Netherlands, Belgium, Germany, and Denmark and low-lying areas of eastern England particularly around The Wash and Fens . Storm surges are caused by changes in barometric pressure combined with strong wind created wave action . The first recorded storm tide flood was the Julianenflut , on 17 February 1164. In its wake, the Jadebusen , (a bay on the coast of Germany), began to form. A storm tide in 1228
11868-465: The construction of the Pepsi Center (which opened in 1999) where the two franchises play today, and costs began to put a drain on business. In 1997, COMSAT agreed in principle to sell Ascent to Liberty Media . However, Liberty was not interested in sports ownership at the time (though it has since bought Major League Baseball 's Atlanta Braves ), and made the deal contingent upon Ascent selling
12006-437: 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
12144-586: The decline. For example, a resident orca pod was lost in the 1960s, presumably due to the peak in PCB pollution in this time period. The OSPAR commission manages the OSPAR convention to counteract the harmful effects of human activity on wildlife in the North Sea, preserve endangered species , and provide environmental protection. All North Sea border states are signatories of the MARPOL 73/78 Accords, which preserve
12282-519: 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
12420-537: 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
12558-422: 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
12696-555: The energy of the incoming sea, so that the dike itself does not receive the full impact. Dikes that lie directly on the sea are especially reinforced. The dikes have, over the years, been repeatedly raised, sometimes up to 9 metres (30 ft) and have been made flatter to better reduce wave erosion. Where the dunes are sufficient to protect the land behind them from the sea, these dunes are planted with beach grass ( Ammophila arenaria ) to protect them from erosion by wind, water, and foot traffic. Storm surges threaten, in particular,
12834-403: 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
12972-572: The finest fishing location of the North Sea. The Long Forties and the Broad Fourteens are large areas with roughly uniform depth in fathoms (forty fathoms and fourteen fathoms or 73 and 26 m or 240 and 85 ft deep, respectively). These great banks and others make the North Sea particularly hazardous to navigate, which has been alleviated by the implementation of satellite navigation systems . The Devil's Hole lies 320 kilometres (200 mi) east of Dundee , Scotland. The feature
13110-596: The goal of global satellite coverage that today has 143 member countries and signatories. COMSAT was responsible for the launching of the Early Bird communications satellite , on 6 April 1965. To further satellite technology, in September 1969, COMSAT opened COMSAT Laboratories, a research, and development arm, in Clarksburg, Maryland . The founding director of COMSAT Labs was Bill Pritchard from 1969 to 1973. He
13248-531: The highest variability where there is fresh water inflow, such as at the Rhine and Elbe estuaries, the Baltic Sea exit and along the coast of Norway. The main pattern to the flow of water in the North Sea is an anti-clockwise rotation along the edges. The North Sea is an arm of the Atlantic Ocean receiving the majority of ocean current from the northwest opening, and a lesser portion of warm current from
13386-431: 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
13524-568: The initial operating system for the International Maritime Satellite Organization ( INMARSAT ). COMSAT provided 2-way communication via geostationary satellite for a number of cruise ships in Caribbean and other offshore applications. The ship on-board system included an antenna stabilized with 3-axis gimbals, beacon signal receiver and an active control system to search and lock the antenna on
13662-552: 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
13800-489: The marine environment by preventing pollution from ships. Germany, Denmark, and the Netherlands also have a trilateral agreement for the protection of the Wadden Sea , or mudflats , which run along the coasts of the three countries on the southern edge of the North Sea. The North Sea has had various names throughout history. One of the earliest recorded names was Septentrionalis Oceanus , or "Northern Ocean", which
13938-479: The medium for transmitting signals. These networks were used for telegraphy and telephony for many decades. In 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
14076-567: 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
14214-414: 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
14352-742: 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
14490-596: 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
14628-452: 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
14766-400: 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
14904-537: The other 20% available on NASDAQ . The franchises took convincingly different directions in terms of on-court/ice production: the Nuggets were perennially among the worst teams in the NBA (bottoming out with an 11–71 record in 1997–98 ), while the Avalanche won a Stanley Cup in their first season in Colorado ( 1996 ) and five consecutive division trophies under Ascent's watch. In addition, COMSAT/Ascent were responsible for
15042-515: 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
15180-500: The prevailing flood levels. It was only around the beginning of the High Middle Ages , in 1200 AD, that inhabitants began to connect single ring dikes into a dike line along the entire coast, thereby turning amphibious regions between the land and the sea into permanent solid ground. The modern form of the dikes supplemented by overflow and lateral diversion channels, began to appear in the 17th and 18th centuries, built in
15318-709: 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,
15456-624: The satellite during the ship maneuvers and severe waves. The system called Startrack was developed by the Canadian company Techwest Data Systems. In 1995, the system was acquired by the UK Marine Data Systems for their floating rigs operations in the North Sea and in 1996 manufacturing moved to Aberdeen , Scotland . Between 1998 and 2000, COMSAT merged with Lockheed Martin Corp . In a US$ 2.7 billion merger, to become an element of
15594-564: The satellite services business, to Telenor of Norway for US$ 116.5 million. This sale was completed on 11 January 2002, and included COMSAT mobile's two Earth station facilities, one in Southbury, Connecticut, and one in Santa Paula, California. Viasat, Inc. acquired COMSAT Laboratories from Lockheed Martin in 2001. On 7 December 2001, Lockheed Martin announced plans to exit its Global Telecommunications services business, disbanding
15732-469: The sea creating deep fjords and archipelagos . South of Stavanger, the coast softens, the islands become fewer. The eastern Scottish coast is similar, though less severe than Norway. From north east of England , the cliffs become lower and are composed of less resistant moraine , which erodes more easily, so that the coasts have more rounded contours. In the Netherlands, Belgium and in East Anglia
15870-413: The shores of the sea clogging harbours and inlets and has become a nuisance. Due to the heavy human populations and high level of industrialization along its shores, the wildlife of the North Sea has suffered from pollution, overhunting, and overfishing. Flamingos and pelicans were once found along the southern shores of the North Sea, but became extinct over the second millennium. Walruses frequented
16008-471: The smaller opening at the English Channel. These tidal currents leave along the Norwegian coast. Surface and deep water currents may move in different directions. Low salinity surface coastal waters move offshore, and deeper, denser high salinity waters move inshore. The North Sea located on the continental shelf has different waves from those in deep ocean water. The wave speeds are diminished and
16146-557: The south, the coast consists mainly of sandy beaches, estuaries of long rivers and wide mudflats . Due to the dense population, heavy industrialisation , and intense use of the sea and the area surrounding it, various environmental issues affect the sea's ecosystems. Adverse environmental issues – commonly including overfishing , industrial and agricultural runoff , dredging , and dumping, among others – have led to several efforts to prevent degradation and to safeguard long-term economic benefits. The North Sea
16284-651: The subsidiary Lockeed Martin Global Telecommunications (LMGT). COMSAT's ticker symbol CQ was removed from the New York Stock Exchange on 2 August 2000. During the two-year approval process, Comsat shareholders lost about US$ 300 million in purchase value because of a drop in Lockheed Martin stock as the two companies struggled through complex congressional and regulatory hurdles. With the integration of COMSAT, LMGT became
16422-609: The telegraph Charles Wheatstone and Samuel Morse , numerous inventors and developers of 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
16560-412: 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
16698-511: 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
16836-825: The uplands of the Fennoscandian Shield and the British Isles. This precursor of the current North Sea has grown and shrunk with the rise and fall of the eustatic sea level during geologic time. Sometimes it was connected with other shallow seas, such as the sea above the Paris Basin to the south-west, the Paratethys Sea to the south-east, or the Tethys Ocean to the south. During the Late Cretaceous, about 85 million years ago , all of modern mainland Europe except for Scandinavia
16974-490: 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
17112-568: The war on the side of Japan. During the First World War , Great Britain's Grand Fleet and Germany's Kaiserliche Marine faced each other in the North Sea, which became the main theatre of the war for surface action. Britain's larger fleet and North Sea Mine Barrage were able to establish an effective blockade for most of the war, which restricted the Central Powers ' access to many crucial resources. Major battles included
17250-492: 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
17388-406: The wave amplitudes are increased. In the North Sea there are two amphidromic systems and a third incomplete amphidromic system. In the North Sea the average tide difference in wave amplitude is between zero and eight metres (26 ft). The Kelvin tide of the Atlantic Ocean is a semidiurnal wave that travels northward. Some of the energy from this wave travels through the English Channel into
17526-668: The wholly owned LMGT subsidiary and immediately implementing actions to reassign certain of LMGT's businesses and investments to other operating segments of Lockheed Martin, sell the remaining operations, position investments for monetization, and eliminate the LMGT administrative structure. The COMSAT General telecommunications unit was realigned with the Space Systems business area. COMSAT International Holdings (CIH), formerly known as World Data Consortium, acquired an 81% of COMSAT International (formerly Enterprise Solutions-International,
17664-418: 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
17802-532: Was a scattering of islands. By the Early Oligocene , 34 to 28 million years ago , the emergence of Western and Central Europe had almost completely separated the North Sea from the Tethys Ocean, which gradually shrank to become the Mediterranean as Southern Europe and South West Asia became dry land. The North Sea was cut off from the English Channel by a narrow land bridge until that
17940-566: Was breached by at least two catastrophic floods between 450,000 and 180,000 years ago. Since the start of the Quaternary period about 2.6 million years ago , the eustatic sea level has fallen during each glacial period and then risen again. Every time the ice sheet reached its greatest extent, the North Sea became almost completely dry, the dry landmass being known as Doggerland , whose northern regions were themselves known to have been glaciated. The present-day coastline formed after
18078-632: Was cited by Pliny . He also noted that the Cimbri called it Morimarusa – "Dead Sea". The name "North Sea" probably came into English, however, via the Dutch Noordzee , who named it thus either in contrast with the Zuiderzee ("South Sea"), located south of Frisia , or because the sea is generally to the north of the Netherlands. Before the adoption of "North Sea", the names used in English were "German Sea" or "German Ocean", referred to as
18216-653: Was created by the Communications Satellite Act of 1962 and incorporated as a publicly traded company on February 1, 1963. The primary goal of COMSAT was to serve as a public, federally funded corporation intended to develop a commercial and international satellite communication system. Although the corporation was government regulated, it was equally owned by some major communications corporations and independent investors. COMSAT began operations with its headquarters in Washington, D.C. , in 1962, with
18354-490: 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
18492-407: 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
18630-715: Was followed by Burton Edelson , director from 1973 to 1982. Director from 1982 to 1995 Dr. John V. Evans, Dr. Ramesh K. Gupta, director from 1995 to 2000. Following many open inquiries into ongoing disagreements with major broadcasting companies and COMSAT, the FCC created the Open Skies Policy in June 1972. This policy authorized the use of satellites for domestic broadcast use and encouraged competition between different systems. In 1976, COMSAT deployed Marisat , three geosynchronous satellite systems providing mobile services to
18768-471: 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
18906-571: 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 ,
19044-486: 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
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