|
Transatlantic Telecommunications Cable
A transatlantic telecommunications cable is a submarine communications cable connecting one side of the Atlantic Ocean to the other. In the 19th and early 20th centuries, each cable was a single wire. After mid-century, coaxial cable came into use, with amplifiers. Late in the 20th century, all cables installed used optical fiber as well as optical amplifiers, because distances range thousands of kilometers. History When the first transatlantic telegraph cable was laid in 1858 by Cyrus West Field, it operated for only three weeks; subsequent attempts in 1865 and 1866 were more successful. In July 1866 '' Great Eastern'' sailed out of Valentia Island, Ireland and on July 26th landed at Hearts Content in Newfoundland. It was active until 1965. Although a telephone cable was discussed starting in the 1920s, to be practical it needed a number of technological advances which did not arrive until the 1940s. Starting in 1927, transatlantic telephone service was radio-based. TAT-1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submarine Communications Cable
A submarine communications cable is a cable laid on the sea bed between land-based stations to carry telecommunication signals across stretches of ocean and sea. The first submarine communications cables laid beginning in the 1850s carried telegraphy traffic, establishing the first instant telecommunications links between continents, such as the first transatlantic telegraph cable which became operational on 16 August 1858. Subsequent generations of cables carried telephone traffic, then data communications traffic. Modern cables use optical fibre technology to carry digital data, which includes telephone, Internet and private data traffic. Modern cables are typically about in diameter and weigh around for the deep-sea sections which comprise the majority of the run, although larger and heavier cables are used for shallow-water sections near shore. Submarine cables first connected all the world's continents (except Antarctica) when Java was connected to Darwin, Northern Terr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CS Monarch (1945)
HMTS ''Monarch'', launched on 8 August 1945 and completed during February 1946, was the fourth cable ship with that name. The ship was built for the General Post Office (GPO) for the laying and repair of submarine communications cable and was the largest cable ship in the world when completed and the first cable ship to have all electric cable machinery. The ship was first engaged in repair and update of existing cables which had been neglected during the war. ''Monarch'' laid the first transatlantic telephone cable TAT-1. In 1969 When the GPO became a public corporation, the Post Office, the designation "Her Majesty's Telegraph Ship" (H.M.T.S.) became the more conventional, commercial designation "Cable Ship" (CS). In 1970 the ship was sold to Cable & Wireless and renamed ''Sentinel''.A fifth, smaller, ''Monarch'' for the Post Office was launched in 1975. Background The war loss of left Britain without a large cable ship. The government decided the national need for such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SACS (cable System)
The South Atlantic Cable System or SACS ( pt, link=no, Sistema de Cabo do Atlântico Sul), is a submarine communications cable in the South Atlantic Ocean linking Luanda, Angola with Fortaleza, Brazil with a leg connecting the Brazilian archipelago of Fernando de Noronha as well. It is the first low latency routing between Africa and South America. The undersea cable measures 6,165 km in length and has been designed with 100Gbps coherent WDM technology - with 4 fiber pairs and offers a total capacity of 40 Tbit/s between Brazil and Angola. In September 2018 Angola Cables announced that the SACS cable was on-line and ready to begin commercial operation. It was also reported at this point that it was NEC who was supplying the technology for the cable. With SACS cable now in operation, data traffic between Angola and Brazil will no longer have to pass through Europe and the US, as was the case previously. The South Atlantic Cable System is owned and operated by Angola Cable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hibernia Atlantic
Hibernia Networks, alternately known as Hibernia Atlantic, was a privately held, US-owned provider of telecommunication services. It operated global network routes on self-healing rings in North America, Europe and Asia including submarine communications cable systems in the North Atlantic Ocean which connected Canada, the United States, the Republic of Ireland, the United Kingdom and mainland Europe. Hibernia managed cable landing stations in Dublin, Republic of Ireland; Coleraine, Northern Ireland; Southport, England; Halifax, Canada; Lynn, Massachusetts, United States. Hibernia's network provided service, from 2.5 Gbit/s to 100 Gbit/s wavelengths and Ethernet from 10 Mbit/s to 100 Gbit/s. It also provided traditional SONET/SDH services. In January 2017, the company was acquired and absorbed into GTT Communications, Inc. It was previously a subsidiary of Columbia Ventures Corporation (CVC) and was owned by both CVC and Constellation Ventures Partners. Hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latency (audio)
Latency refers to a short period of delay (usually measured in milliseconds) between when an audio signal enters a system and when it emerges. Potential contributors to latency in an audio system include analog-to-digital conversion, buffering, digital signal processing, transmission time, digital-to-analog conversion and the speed of sound in the transmission medium. Latency can be a critical performance metric in professional audio including sound reinforcement systems, foldback systems (especially those using in-ear monitors) live radio and television. Excessive audio latency has the potential to degrade call quality in telecommunications applications. Low latency audio in computers is important for interactivity. Telephone calls In all systems, latency can be said to consist of three elements: codec delay, playout delay and network delay. Latency in telephone calls is sometimes referred to as delay; the telecommunications industry also uses the term ''quality of experie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Satellite
A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. Communications satellites are used for television, telephone, radio, internet, and military applications. Many communications satellites are in geostationary orbit above the equator, so that the satellite appears stationary at the same point in the sky; therefore the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track the satellite. Others form satellite constellations in low Earth orbit, where antennas on the ground have to follow the position of the satellites and switch between satellites frequently. The high frequency radio waves used for telecommunications links travel by line of sight and so are obstructed by the curve of the Earth. The purpose of communications sate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Self-healing Ring
A self-healing ring, or SHR, is a telecommunications term for loop network topology, a common configuration in telecommunications transmission systems. Like roadway and water distribution systems, a loop or ring is used to provide redundancy. SDH, SONET and WDM systems are often configured in self-healing rings. Description The system consists of a ring of bidirectional links between a set of stations, typically using optical fiber communications. In normal use, traffic is dispatched in the direction of the shortest path towards its destination. In the event of the loss of a link, or of an entire station, the two nearest surviving stations "loop back" their ends of the ring. In this way, traffic can still travel to all surviving parts of the ring, even if it has to travel "the long way round". A second break in the ring may divide it into two sub-rings, but in such a case each sub-ring will remain functional. Advantages Self-healing rings offer high levels of resilien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New York City
New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the List of United States cities by population density, most densely populated major city in the United States, and is more than twice as populous as second-place Los Angeles. New York City lies at the southern tip of New York (state), New York State, and constitutes the geographical and demographic center of both the Northeast megalopolis and the New York metropolitan area, the largest metropolitan area in the world by urban area, urban landmass. With over 20.1 million people in its metropolitan statistical area and 23.5 million in its combined statistical area as of 2020, New York is one of the world's most populous Megacity, megacities, and over 58 million people live within of the city. New York City is a global city, global Culture of New ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
London
London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a major settlement for two millennia. The City of London, its ancient core and financial centre, was founded by the Romans as '' Londinium'' and retains its medieval boundaries.See also: Independent city § National capitals The City of Westminster, to the west of the City of London, has for centuries hosted the national government and parliament. Since the 19th century, the name "London" has also referred to the metropolis around this core, historically split between the counties of Middlesex, Essex, Surrey, Kent, and Hertfordshire, which largely comprises Greater London, governed by the Greater London Authority.The Greater London Authority consists of the Mayor of London and the London Assembly. The London Mayor is distinguished fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Circle Route
Great-circle navigation or orthodromic navigation (related to orthodromic course; from the Greek ''ορθóς'', right angle, and ''δρóμος'', path) is the practice of navigating a vessel (a ship or aircraft) along a great circle. Such routes yield the shortest distance between two points on the globe. Course The great circle path may be found using spherical trigonometry; this is the spherical version of the '' inverse geodetic problem''. If a navigator begins at ''P''1 = (φ1,λ1) and plans to travel the great circle to a point at point ''P''2 = (φ2,λ2) (see Fig. 1, φ is the latitude, positive northward, and λ is the longitude, positive eastward), the initial and final courses α1 and α2 are given by formulas for solving a spherical triangle :\begin \tan\alpha_1&=\frac,\\ \tan\alpha_2&=\frac,\\ \end where λ12 = λ2 − λ1In the article on great-circle distances, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fiber Optic
An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to transmit light between the two ends of the fiber and find wide usage in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths (data transfer rates) than electrical cables. Fibers are used instead of metal wires because signals travel along them with less loss; in addition, fibers are immune to electromagnetic interference, a problem from which metal wires suffer. Fibers are also used for illumination and imaging, and are often wrapped in bundles so they may be used to carry light into, or images out of confined spaces, as in the case of a fiberscope. Specially designed fibers are also used for a variety of other applications, some of them being fiber optic sensors and fiber lasers. Op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
