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A transatlantic telecommunications cable is a
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 tel ...
connecting one side of the
Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
to the other. In the 19th and early 20th centuries, each cable was a single wire. After mid-century,
coaxial cable Coaxial cable, or coax (pronounced ) is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric ( insulating material); many coaxial cables also have a p ...
came into use, with amplifiers. Late in the 20th century, all cables installed used
optical fiber 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 Hair is a protein filament that grows ...
as well as
optical amplifier An optical amplifier is a device that amplifies an optical signal directly, without the need to first convert it to an electrical signal. An optical amplifier may be thought of as a laser without an optical cavity, or one in which feedback fr ...
s, because distances range thousands of kilometers.


History

When the first
transatlantic telegraph cable Transatlantic telegraph cables were undersea cables running under the Atlantic Ocean for telegraph communications. Telegraphy is now an obsolete form of communication, and the cables have long since been decommissioned, but telephone and data a ...
was laid in 1858 by
Cyrus West Field Cyrus West Field (November 30, 1819July 12, 1892) was an American businessman and financier who, along with other entrepreneurs, created the Atlantic Telegraph Company and laid the first telegraph cable across the Atlantic Ocean in 1858. Early ...
, 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 Valentia Island () is one of Ireland's most westerly points. It lies off the Iveragh Peninsula in the southwest of County Kerry. It is linked to the mainland by the Maurice O'Neill Memorial Bridge at Portmagee. A car ferry also departs from ...
,
Ireland Ireland ( ; ga, Éire ; Ulster-Scots: ) is an island in the North Atlantic Ocean, in north-western Europe. It is separated from Great Britain to its east by the North Channel, the Irish Sea, and St George's Channel. Ireland is the s ...
and on July 26th landed at Hearts Content in
Newfoundland Newfoundland and Labrador (; french: Terre-Neuve-et-Labrador; frequently abbreviated as NL) is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region ...
. 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 (Transatlantic No. 1) was the first transatlantic telephone cable system. It was laid between Gallanach Bay, near
Oban Oban ( ; ' in Scottish Gaelic meaning ''The Little Bay'') is a resort town within the Argyll and Bute council area of Scotland. Despite its small size, it is the largest town between Helensburgh and Fort William. During the tourist season, ...
, and
Clarenville Clarenville is a town on the east coast of Newfoundland in the province of Newfoundland and Labrador, Canada. Clarenville was incorporated in 1951. It is located in the Shoal Harbour valley, fronting an arm of the Atlantic Ocean called Random S ...
,
Newfoundland Newfoundland and Labrador (; french: Terre-Neuve-et-Labrador; frequently abbreviated as NL) is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region ...
between 1955 and 1956 by the cable ship ''
Monarch A monarch is a head of stateWebster's II New College DictionarMonarch Houghton Mifflin. Boston. 2001. p. 707. Life tenure, for life or until abdication, and therefore the head of state of a monarchy. A monarch may exercise the highest authority ...
''. It was inaugurated on September 25, 1956, initially carrying 36 telephone channels. In the first 24 hours of public service, there were 588 London–U.S. calls and 119 from London to Canada. The capacity of the cable was soon increased to 48 channels. Later, an additional three channels were added by use of C Carrier equipment.
Time-assignment speech interpolation In telecommunication, a time-assignment speech interpolation (TASI) was an analog technique used on certain long transmission links to increase voice-transmission capacity. TASI was invented by Bell Labs in the early 1960s to increase the capacity ...
(TASI) was implemented on the TAT-1 cable in June 1960 and effectively increased the cable's capacity from 37 (out of 51 available channels) to 72 speech circuits. TAT-1 was finally retired in 1978. Later coaxial cables, installed through the 1970s, used
transistor upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch ...
s and had higher bandwidth. The
Moscow–Washington hotline The Moscow–Washington hotline (formally known in the United States as the Washington–Moscow Direct Communications Link; rus, Горячая линия Вашингтон — Москва, r=Goryachaya liniya Vashington–Moskva) is a system t ...
was initially connected through this system.


Current technology

All cables presently in service use
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 t ...
technology. Many cables terminate in Newfoundland and Ireland, which lie on the
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 ro ...
from
London London is the capital and List of urban areas in the United Kingdom, 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 dow ...
, UK to
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 L ...
, US. There has been a succession of newer transatlantic cable systems. All recent systems have used
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 t ...
transmission, and a
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 redundanc ...
topology. Late in the 20th century,
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 ...
s lost most of their North Atlantic telephone traffic to these low-cost, high-capacity, low- latency cables. This advantage only increases over time, as tighter cables provide higher bandwidth – the 2012 generation of cables drop the transatlantic latency to under 60 milliseconds, according to
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 commu ...
, deploying such a cable that year. Some new cables are being announced on the South Atlantic: SACS (South Atlantic Cable System) and SAex (South Atlantic Express).


TAT cable routes

The TAT series of cables constitute a large percentage of all North Atlantic cables. All TAT cables are joint ventures between a number of
telecommunications Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that ...
companies, e.g.
British Telecom BT Group plc (trading as BT and formerly British Telecom) is a British multinational telecommunications holding company headquartered in London, England. It has operations in around 180 countries and is the largest provider of fixed-line, b ...
. CANTAT cables terminate in Canada rather than in the US.


Private cable routes

There are a number of private non-TAT cables.


South Atlantic cable routes


See also

*
Cable layer A cable layer or cable ship is a deep-sea vessel designed and used to lay underwater cables for telecommunications, electric power transmission, military, or other purposes. Cable ships are distinguished by large cable sheaves for guiding c ...
* List of international submarine communications cables


References


External links

*
Aronsson's Telecom History TimelineSubmarine Cable Landings Worldwide
{{DEFAULTSORT:Transatlantic Telephone Cable History of the telephone History of telecommunications in the United States History of telecommunications in the United Kingdom