A cross-section of a submarine communications cable. 1. Polyethylene. 2. "Mylar" tape. 3. Stranded steel wires. 4. Aluminum water barrier. 5. Polycarbonate. 6. Copper or aluminum tube. 7. Petroleum jelly. 8. Optical fibers.

Submarine cables are laid using special cable layer ships, such as the modern René Descartes, operated by France Télécom Marine.

A submarine communications cable is a cable laid beneath the sea to carry telecommunications between countries. Cross section may refer to the following In geometry, Cross section is the intersection of a 3-dimensional body with a plane. ... Image File history File linksMetadata Download high-resolution version (2560x1920, 778 KB) France Telecom Marine, cable-laying ship René Descartes, at sunset in the harbor of La Seyne sur Mer (near Toulon, France) Copyright © 2006 David Monniaux File links The following pages on the English Wikipedia link to this file... Image File history File linksMetadata Download high-resolution version (2560x1920, 778 KB) France Telecom Marine, cable-laying ship René Descartes, at sunset in the harbor of La Seyne sur Mer (near Toulon, France) Copyright © 2006 David Monniaux File links The following pages on the English Wikipedia link to this file... A cable layer is a deep-sea vessel designed and used to lay underwater cables for telecommunications, electricity, and such. ... Descartes redirects here. ... France Télécom (Euronext: FTE, NYSE: FTE) (often spelled France Telecom, without the accents, in non-French text) is the main telecommunication company in France. ... Telecommunication involves the transmission of signals over a distance for the purpose of communication. ...

The first submarine communications cables carried telegraphy traffic. Subsequent generations of cables carried first telephony traffic, then data communications traffic. All modern cables use fibre optic technology to carry digital payloads, which are then used to carry telephone traffic as well as Internet and private data traffic. They are typically 69 mm in diameter and weigh around 10 kg per meter, although thinner and lighter cables are used for deep water sections.^[1] Telegraph and Telegram redirect here. ... For other uses, see Telephone (disambiguation). ... A computer network is a system for communication among two or more computers. ... Fiber Optic strands An optical fiber in American English or fibre in British English is a transparent thin fiber for transmitting light. ...

As of 2003, submarine cables link all the world's continents except Antarctica. Animated, colour-coded map showing the various continents. ...

History

Trials

After William Cooke and Charles Wheatstone had introduced their working telegraph in 1839, the idea of a submarine line across the Atlantic Ocean began to be thought of as a possible triumph of the future. Samuel Morse proclaimed his faith in it as early as the year 1840, and in 1842 he submerged a wire, insulated with tarred hemp and India rubber,^[2][3] in the water of New York harbour, and telegraphed through it. The following autumn Wheatstone performed a similar experiment in Swansea bay. A good insulator to cover the wire and prevent the electric current from leaking into the water was necessary for the success of a long submarine line. India rubber had been tried by Moritz von Jacobi, the Prussian electrician, as far back as the early 1800s. Wikipedia does not yet have an article with this exact name. ... Charles Wheatstone Sir Charles Wheatstone (February 6, 1802 - October 19, 1875) was the British inventor of many innovations including the English concertina the Stereoscope an early form of microphone the Playfair cipher (named for Lord Playfair, the person who publicized it) He was a major figure in the development of... Telegraph and Telegram redirect here. ... Portrait of Samuel F. B. Morse by Mathew Brady, between 1855 and 1865 Samuel Finley Breese Morse (April 27, 1791 – April 2, 1872) was an American inventor, and painter of portraits and historic scenes; he is most famous for inventing the electric telegraph and Morse code. ... U.S. Marihuana production permit. ... Rubber is an elastic hydrocarbon polymer which occurs as a milky emulsion (known as latex) in the sap of a number of plants but can also be produced synthetically. ... This article is about the state. ... For other places with the same name, see Swansea (disambiguation). ... This article or section is in need of attention from an expert on the subject. ... Moritz Hermann von Jacobi Moritz Hermann (Boris Semyonovich) von Jacobi (Russian: ) (September 21, 1801 – March 10, 1874) was a Prussian engineer and physicist born in Potsdam. ... For other uses, see Prussia (disambiguation). ... TVA electricians, Tennessee, 1942. ...

Another insulating gum which could be melted by heat and readily applied to wire made its appearance in 1842. Gutta-percha, the adhesive juice of the Palaquium gutta tree, was introduced to Europe by William Montgomerie, a Scottish surgeon in the service of the British East India Company. Twenty years earlier he had seen whips made of it in Singapore, and he believed that it would be useful in the fabrication of surgical apparatus. Michael Faraday and Wheatstone soon discovered the merits of gutta-percha as an insulator, and in 1845 the latter suggested that it should be employed to cover the wire which was proposed to be laid from Dover to Calais. It was tried on a wire laid across the Rhine between Deutz and Cologne. In 1849 C.V. Walker, electrician to the South Eastern Railway, submerged a wire coated with it, or, as it is technically called, a gutta-percha core, along the coast off Dover. Species About 100-120 species, including: Palaquium amboinense Palaquium barnesii Palaquium bataanense Palaquium beccarianum Palaquium borneense Palaquium burckii Palaquium clarkeanum Palaquium cochleariifolium Palaquium dasyphyllum Palaquium ellipticum Palaquium formosanum Palaquium galactoxylum Palaquium gutta Palaquium herveyi Palaquium hexandrum Palaquium hispidum Palaquium hornei Palaquium impressinervium Palaquium kinabaluense Palaquium lanceolatum Palaquium leiocarpum Palaquium lobbianum... This article is about the country. ... “Surgeon” redirects here. ... The British East India Company, sometimes referred to as John Company, was the first joint-stock company (the Dutch East India Company was the first to issue public stock). ... Michael Faraday, FRS (September 22, 1791 – August 25, 1867) was an English chemist and physicist (or natural philosopher, in the terminology of that time) who contributed to the fields of electromagnetism and electrochemistry. ... , Dover is a major channel port in the English county of Kent. ... Calais (Kales in Dutch) is a town in northern France, located at 50°57N 1°52E. It is in the département of Pas-de-Calais, of which it is a sous-préfecture. ... For other uses, see Rhine (disambiguation). ... There are multiple topics for Deutz Deutz, Germany: the town in North Rhine-Westphalia, Germany Deutz AG: a diesel-engine manufacturer in Germany. ... For other uses, see Cologne (disambiguation). ... The London and Greenwich Railway (LGR) and the Canterbury and Whitstable Railway (CWR) in East Kent were the earliest railways to serve the then county of Kent: eventually both became parts of the South Eastern Railway (SER). ...

The first commercial cables

In August 1850, John Watkins Brett's Anglo-French Telegraph Company laid the first line across the English Channel. It was simply a copper wire coated with gutta-percha, without any other protection. The experiment served to keep alive the concession, and the next year, on November 13, 1851, a protected core, or true cable, was laid from a government hulk, the Blazer, which was towed across the Channel. The next year, Great Britain and Ireland were linked together. In 1852, a cable laid by the Submarine Telegraph Company linked London to Paris for the first time. In May, 1853, England was joined to the Netherlands by a cable across the North Sea, from Orford Ness to The Hague. It was laid by the Monarch, a paddle steamer which had been fitted for the work. For the Thoroughbred racehorse of the same name, see English Channel (horse). ... For other uses, see Copper (disambiguation). ... Species About 100-120 species, including: Palaquium amboinense Palaquium barnesii Palaquium bataanense Palaquium beccarianum Palaquium borneense Palaquium burckii Palaquium clarkeanum Palaquium cochleariifolium Palaquium dasyphyllum Palaquium ellipticum Palaquium formosanum Palaquium galactoxylum Palaquium gutta Palaquium herveyi Palaquium hexandrum Palaquium hispidum Palaquium hornei Palaquium impressinervium Palaquium kinabaluense Palaquium lanceolatum Palaquium leiocarpum Palaquium lobbianum... A concession is a facility operated under a contract or license. ... is the 317th day of the year (318th in leap years) in the Gregorian calendar. ... 1851 (MDCCCLI) was a common year starting on Wednesday (see link for calendar) of the Gregorian calendar (or a common year starting on Friday of the 12-day-slower Julian calendar). ... A hulk is a ship that is afloat, but incapable of going to sea. ... This article is about the capital of England and the United Kingdom. ... This article is about the capital of France. ... The North Sea is a sea of the Atlantic Ocean, located between the coasts of Norway and Denmark in the east, the coast of the British Isles in the west, and the German, Dutch, Belgian and French coasts in the south. ... Orford Ness, described by a BBC documentary as half wilderness, half military junkyard, is a peninsula on the Suffolk coast in Great Britain, linked to the mainland at Aldeburgh and stretching along the coast to Orford. ... Hague redirects here. ... A paddle steamer, paddleboat, or paddlewheeler is a ship or boat propelled by one or more paddle wheels driven by a steam engine. ...

Transatlantic telegraph cable

Main article: Transatlantic telegraph cable

The first attempt at laying a transatlantic telegraph cable was promoted by Cyrus West Field, who persuaded British industrialists to fund and lay one in 1858. However, the technology of the day was not capable of supporting the project, it was plagued with problems from the outset, and was in operation for only a month. Subsequent attempts in 1865 and 1866 with the world's largest steamship, the SS Great Eastern, used a more advanced technology and produced the first successful transatlantic cable. The Great Eastern later went on to lay the first cable to India in 1870. The first transatlantic telegraph cable crossed the Atlantic Ocean from Foilhommerum, Valentia Island, in western Ireland to Hearts Content, in eastern Newfoundland. ... The first transatlantic telegraph cable crossed the Atlantic Ocean from Foilhommerum, Valentia Island, in western Ireland to Hearts Content, in eastern Newfoundland. ... Cyrus West Field Cyrus West Field c. ... The SS Great Eastern was an iron sailing steam ship designed by Isambard Kingdom Brunel. ...

Submarine cable to India, Singapore, the Far East and Australasia

An 1863 cable to Mumbai provided a crucial link to Saudi Arabia.^[4] In 1870 Bombay was linked to London via submarine cable in a combined operation by four cable companies, at the behest of the British Government. In 1872 these four companies were combined to form the mammoth globespanning Eastern Telegraph Company, owned by John Pender. A spin-off from Eastern Telegraph Company was a second sister company, the Eastern Extension, China and Australasia Telegraph Company, commonly known simply as "the Extension". , Bombay redirects here. ...

Submarine cable across the Pacific

This was completed in 1902–03, linking the US mainland to Hawaii in 1902 and Guam to the Philippines in 1903.^[5] Canada, Australia, New Zealand and Fiji were also linked in 1902.^[6]

The North Pacific Cable system was the first laser regenerative (repeatered) system to completely cross the Pacific from the US mainland to Japan. The US portion of NPC was manufactured in Portland Oregon in 1990 at STC Submarine Systems, and later Alcatel Submarine Networks (the plant was shutdown in 2001). The system was layed by Cable & Wireless Marine on the CS Cable Venture in 1991.

Construction

Transatlantic cables of the 19th century consisted of an outer layer of iron and later steel wire, wrapping India rubber, wrapping gutta-percha, which surrounded a multi-stranded copper wire at the core. The portions closest to each shore landing had additional protective armor wires. Gutta-percha, a natural polymer similar to rubber, had nearly ideal properties for insulating submarine cables, with the exception of a rather high dielectric constant which made cable capacitance high. Gutta-percha was not replaced as a cable insulation until polyethylene was introduced in the 1930s. Gutta-percha was so critical to communications that in the 1920s the American military experimented with rubber-insulated cables, since American interests controlled significant supplies of rubber but no gutta-percha manufacturers. General Name, symbol, number iron, Fe, 26 Chemical series transition metals Group, period, block 8, 4, d Appearance lustrous metallic with a grayish tinge Standard atomic weight 55. ... For other uses, see Steel (disambiguation). ... Species About 100-120 species, including: Palaquium amboinense Palaquium barnesii Palaquium bataanense Palaquium beccarianum Palaquium borneense Palaquium burckii Palaquium clarkeanum Palaquium cochleariifolium Palaquium dasyphyllum Palaquium ellipticum Palaquium formosanum Palaquium galactoxylum Palaquium gutta Palaquium herveyi Palaquium hexandrum Palaquium hispidum Palaquium hornei Palaquium impressinervium Palaquium kinabaluense Palaquium lanceolatum Palaquium leiocarpum Palaquium lobbianum... A polymer (from Greek: πολυ, polu, many; and μέρος, meros, part) is a substance composed of molecules with large molecular mass composed of repeating structural units, or monomers, connected by covalent chemical bonds. ... This does not cite any references or sources. ... A dielectric is a nonconducting substance, i. ... Capacitance is a measure of the amount of electric charge stored (or separated) for a given electric potential. ... This article does not cite any references or sources. ...

Bandwidth problems

Early long-distance submarine telegraph cables exhibited formidable electrical problems. Unlike modern cables, the technology of the 19th century did not allow for in-line repeater amplifiers in the cable. Large voltages were used to attempt to overcome the electrical resistance of their tremendous length but the cables' distributed capacitance and inductive reactance combined to attenuate the telegraph pulses in the line, severely limiting the data rate for telegraph operation. Thus, the cables had very limited bandwidth. For other uses, see Repeater (disambiguation). ... For the British rock band of the same name, see Amplifier (band). ... International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ... Electrical resistance is a measure of the degree to which an electrical component opposes the passage of current. ... Capacitance is a measure of the amount of electric charge stored (or separated) for a given electric potential. ... For magnetic induction, see Magnetic field. ... It has been suggested that Electric reactance be merged into this article or section. ... This article is about Physics. ... In telecommunication, data signaling rate (DSR) is the aggregate rate at which data pass a point in the transmission path of a data transmission system. ... Bandwidth is the difference between the upper and lower cutoff frequencies of, for example, a filter, a communication channel, or a signal spectrum, and is typically measured in hertz. ...

As early as 1823, Francis Ronalds had observed that electric signals were retarded in passing through an insulated wire or core laid underground, and the same effect was noticeable on cores immersed in water, and particularly on the lengthy cable between England and The Hague. Michael Faraday showed that the effect was caused by capacitance between the wire and the earth (or water) surrounding it. Faraday had noted that when a wire is charged from a battery (for example when pressing a telegraph key), the electric charge in the wire induces an opposite charge in the water as it travels along. As the two charges attract each other, the exciting charge is retarded. The core acts as a capacitor distributed along the length of the cable which, coupled with the resistance and inductance of the cable limits the speed at which a signal travels through the conductor of the cable. Sir Francis Ronalds (1788-1873) was a meteorologist, an inventor and a pioneer of the electric telegraph. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... Michael Faraday, FRS (September 22, 1791 – August 25, 1867) was an English chemist and physicist (or natural philosopher, in the terminology of that time) who contributed to the fields of electromagnetism and electrochemistry. ... It has been suggested that Ground conductor be merged into this article or section. ... For other uses, see Battery. ... This box:      Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ... See Capacitor (component) for a discussion of specific types. ... An electric current i flowing around a circuit produces a magnetic field and hence a magnetic flux Φ through the circuit. ... This article does not cite any references or sources. ... In telecommunication, signalling (or signaling) has the following meanings: The use of signals for controlling communications. ... Conduction is the movement of electrically charged particles through a transmission medium (electrical conductor). ... A submarine communications cable is a cable laid beneath the sea to carry telecommunications between countries. ...

Early cable designs failed to analyze these effects correctly. Famously, E.O.W. Whitehouse had dismissed the problems and insisted that a transatlantic cable was feasible. When he subsequently became electrician of the Atlantic Telegraph Company he became involved in a public dispute with William Thomson. Whitehouse believed that, with enough voltage, any cable could be driven. Because of the excessive voltages recommended by Whitehouse, Cyrus West Field's first transatlantic cable never worked reliably, and eventually short circuited to the ocean when Whitehouse increased the voltage beyond the cable design limit. Edward Orange Wildman Whitehouse (1816 - January 26, 1890) was an English surgeon, better-known for his utlimately unsuccessful endeavours at electrical engineering on the transatlantic telegraph cable. ... The Atlantic Telegraph Company was a company formed in 1856 to undertake and exploit a commercial telegraph cable across the Atlantic ocean, the first such telecommunications link. ... There have been a number of people named William Thomson: William Thomson, 1st Baron Kelvin, usually known as Lord Kelvin, was a 19th century British physicist. ... For alternate meanings see Short circuit (disambiguation) A short circuit (sometimes known as simply a short) is a fault whereby electricity moves through a circuit in an unintended path, usually due to a connection forming where none was expected. ...

Thomson designed a complex electric-field generator that minimized current by resonating the cable, and a sensitive light-beam mirror galvanometer for detecting the faint telegraph signals. Thomson became wealthy on the royalties of these, and several related inventions. Thomson was elevated to Lord Kelvin for his contributions in this area, chiefly an accurate mathematical model of the cable, which permitted design of the equipment for accurate telegraphy. The effects of atmospheric electricity and the geomagnetic field on submarine cables also motivated many of the early polar expeditions. This article is about resonance in physics. ... A mirror galvanometer A mirror galvanometer is a mechanical meter that senses electric current, except that instead of moving a needle, it moves a mirror. ... William Thomson, Archbishop of York, has the same name as this man. ... A mathematical model is an abstract model that uses mathematical language to describe the behaviour of a system. ... Cloud to ground Lightning in the global atmospheric electrical circuit. ... The cause of Earths magnetic field (the surface magnetic field) is not known for certain, but is possibly explained by dynamo theory. ... The International Geophysical Year or IGY was an international scientific effort that lasted from July 1, 1957, to December 31, 1958. ...

Thomson had produced a mathematical analysis of propagation of electrical signals into telegraph cables based on their capacitance and resistance, but since long submarine cables operated at slow rates, he did not include the effects of inductance. By the 1890s, Oliver Heaviside had produced the modern general form of the telegrapher's equations which included the effects of inductance and which were essential to extending the theory of transmission lines to higher frequencies required for high-speed data and voice. Oliver Heaviside (May 18, 1850 – February 3, 1925) was a self-taught English electrical engineer, mathematician, and physicist who adapted complex numbers to the study of electrical circuits, developed techniques for applying Laplace transforms to the solution of differential equations, reformulated Maxwells field equations in terms of electric and... Oliver Heaviside developed the transmission line theory known as the telegraphers equations. ... A transmission line is the material medium or structure that forms all or part of a path from one place to another for directing the transmission of energy, such as electromagnetic waves or acoustic waves, as well as electric power transmission. ... Sine waves of various frequencies; the lower waves have higher frequencies than those above. ...

Transatlantic telephony

Five submarine communication cables crossing the Scottish shore at Scad Head on Hoy, Orkney.

While laying a transatlantic telephone cable was seriously considered from the 1920s, a number of technological advances were required for cost-efficient telecommunications that did not arrive until the 1940s. A first attempt to lay a pupinized telephone cable failed in the early 1930s due to the Great Depression. Image File history File links Download high-resolution version (1958x1468, 1506 KB) These are five submarine telephone/telegraph cables coming ashore at Scad Head on the Isle of Hoy, Orkney. ... Image File history File links Download high-resolution version (1958x1468, 1506 KB) These are five submarine telephone/telegraph cables coming ashore at Scad Head on the Isle of Hoy, Orkney. ... Hoy shown within Orkney Islands Hoy (from Old Norse há-øy meaning high island) is one of the Orkney Islands. ... Location Geography Area Ranked 16th  - Total 990 km²  - % Water  ? Admin HQ Kirkwall ISO 3166-2 GB-ORK ONS code 00RA Demographics Population Ranked 32nd  - Total (2006) 19,800  - Density 20 / km² Scottish Gaelic  - Total () {{{Scottish council Gaelic Speakers}}} Politics Orkney Islands Council http://www. ... For other uses, see Telephone (disambiguation). ... For other uses, see The Great Depression (disambiguation). ...

In 1942, Siemens Brothers of Charlton, London in conjunction with the United Kingdom National Physical Laboratory, adapted submarine communications cable technology to create the world's first submarine oil pipeline in Operation Pluto during World War II. Wilhelm Siemens Carl Wilhelm Siemens (en: Charles William Siemens) (April 4, 1823 – November 19, 1883) was a German engineer. ... Charlton is an area in south-east London, in the London Borough of Greenwich, located between Greenwich and Woolwich. ... The National Physical Laboratory (NPL) is the national measurement standards laboratory for the United Kingdom, based at Bushy Park in Teddington in the London Borough of Richmond upon Thames. ... Operation Pluto (Pipe-Lines Under The Ocean) was a World War II operation by British scientists, oil companies and armed forces to construct undersea oil pipelines under the English Channel between England and France. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000...

TAT-1 (Transatlantic No. 1) was the first transatlantic telephone cable system. Between 1955 and 1956, cable was laid between Gallanach Bay, near Oban, Scotland and Clarenville, Newfoundland and Labrador. It was inaugurated on September 25, 1956, initially carrying 36 telephone channels. TAT-1 (Transatlantic No. ... A transatlantic telephone cable is a submarine communications cable that carries telephone traffic under the Atlantic Ocean. ... For other uses, see Oban (disambiguation). ... Clarenville (2006 pop. ... is the 268th day of the year (269th in leap years) in the Gregorian calendar. ... A car from 1956 Year 1956 (MCMLVI) was a leap year starting on Sunday (link will display full calendar) of the Gregorian calendar. ...

Technological developments

In the 1960s, transoceanic cables were waveguides that transmitted frequency-multiplexed radio signals. A high voltage direct current wire powered the repeaters. These repeaters are among the most reliable vacuum tube amplifiers ever designed.^[7] Many of these cables are still usable, but abandoned because their capacity is too small to be commercially viable. Some have been used as scientific instruments to measure earthquake waves and other geomagnetic events.^[8] Frequency-division multiplexing (FDM) is a form of signal multiplexing where multiple baseband signals are modulated on different frequency carrier waves and added together to create a composite signal. ... Structure of a vacuum tube diode Structure of a vacuum tube triode In electronics, a vacuum tube, electron tube, or (outside North America) thermionic valve or just valve, is a device used to amplify, switch or modify a signal by controlling the movement of electrons in an evacuated space. ...

Diagram of an optical submarine cable repeater.

In the 1980s, fibre optic cables were developed. The first transatlantic telephone cable to use optical fibre was TAT-8, which went into operation in 1988. Image File history File links Submarine_cable_repeater. ... Image File history File links Submarine_cable_repeater. ... Optical fibers An optical fiber (or fibre) is a glass or plastic fiber designed to guide light along its length. ... TAT-8 was AT&Ts 8th transatlantic telephone cable, in operation from 1988, initially carrying 40,000 telephone circuits (simultaneous calls) between USA and France. ...

Modern optical fiber repeaters use a solid-state optical amplifier, usually an Erbium-doped fiber amplifier. Each repeater contains separate equipment for each fibre. These comprise signal reforming, error measurement and controls. A solid-state laser dispatches the signal into the next length of fiber. The solid-state laser excites a short length of doped fiber that itself acts as a laser amplifier. As the light passes through the fibre, it is amplified. This system also permits wavelength-division multiplexing, which dramatically increases the capacity of the fiber. An optical amplifier is a device that amplifies an optical signal directly, without the need to first convert it to an electrical signal. ... In telecommunication, an optical amplifier is a device that amplifies an optical signal directly, without the need to convert it to an electrical signal, or amplify it electrically, and reconvert it to an optical signal. ... In fiber-optic communications, wavelength-division multiplexing (WDM) is a technology which multiplexes multiple optical carrier signals on a single optical fiber by using different wavelengths (colours) of laser light to carry different signals. ...

Repeaters are powered by a constant direct current passed down the conductor near the centre of the cable, so all repeaters in a cable are in series. Power feed equipment is installed at the terminal stations. Typically both ends share the current generation with one end providing a positive voltage and the other a negative voltage. A virtual earth point exists roughly half way along the cable under normal operation. The amplifiers or repeaters derive their power from the potential difference drop across them.

The optic fiber used in undersea cables is chosen for its exceptional clarity, permitting runs of more than 100 kilometers between repeaters to minimize the number of amplifiers and the distortion they cause.

Originally, submarine cables were simple point-to-point connections. With the development of submarine branching units (SBUs), more than one destination could be served by a single cable system. Modern cable systems now usually have their fibres arranged in a self-healing ring to increase their redundancy, with the submarine sections following different paths on the ocean floor. One driver for this development was that the capacity of cable systems had become so large that it was not possible to completely back-up a cable system with satellite capacity, so it became necessary to provide sufficient terrestrial back-up capability. Not all telecommunications organizations wish to take advantage of this capability, so modern cable systems may have dual landing points in some countries (where back-up capability is required) and only single landing points in other countries where back-up capability is either not required, the capacity to the country is small enough to be backed up by other means, or having back-up is regarded as too expensive. A Submarine Branching Unit is a piece of equipment used in submarine telecommunications cable systems to allow the cable to split to serve more than one destination. ... A self-healing ring is a common configuration in telecommunications transmission systems. ... A Cable landing point is the location where a submarine or other underwater cable makes landfall. ...

A further redundant-path development over and above the self-healing rings approach is the "Mesh Network" whereby fast switching equipment is used to transfer services between network paths with little to no effect on higher-level protocols if a path becomes inoperable. As more paths become available to use between two points, the less likely it is that one or two simultaneous failures will prevent end-to-end service.

Cable repair

Cables can be broken by fishing trawlers, anchoring, undersea avalanches and even shark bites. Breaks were common in the early cable laying era due to the use of simple materials and the laying of cables directly on the ocean floor rather than burying the cables in trenches in vulnerable areas. Cables were also sometimes cut by enemy forces in wartime. Cable breaks are by no means a thing of the past, with more than 50 repairs a year in the Atlantic alone,^[9] and significant breaks in 2006 and 2008. For fishing by dragging a baited line after a boat, see troll (angling). ... The 2006 Hengchun earthquake occurred on December 26, 2006 at 12:25 UTC (20:25 local time), with an epicenter off the southwest coast of Taiwan, approximately 22. ...

To effect repairs on deep cables, the damaged portion is brought to the surface using a grapple. Deep cables must be cut at the seabed and each end separately brought to the surface, whereupon a new section is spliced in. The repaired cable is longer than the original, so the excess is deliberately laid in a 'U' shape on the sea-bed. A submersible can be used to repair cables that are near the surface. A grapple is a hook or claw used to catch or hold something. ... This article needs additional references or sources for verification. ...

A number of ports near important cable routes became homes to specialised cable repair ships. Halifax, Nova Scotia was home to a half dozen such vessels for most of the 20th century including long-lived vessels such as the CS Cyrus West Field, CS Minia and CS Mackay-Bennett. The latter two were contracted to recover victims from the sinking of the RMS Titanic. The crews of these vessels developed many new techniques to repair and improve cable laying, such as the "plough", a device to bury cables. Motto: E Mari Merces(Latin) From the Sea, Wealth Coordinates: , Country Province Established April 1, 1996 Government  - Type Regional Municipality  - Mayor Peter Kelly  - Governing body Halifax Regional Council  - MPs List of MPs Alexa McDonough Geoff Regan Michael Savage Peter Stoffer (Bill Casey) (Gerald Keddy) (Peter MacKay)  - MLAs List of MLAs... Motto: Munit Haec et Altera Vincit (Latin: One defends and the other conquers) Capital Halifax Largest city Halifax Regional Municipality Official languages English (de facto) Government Lieutenant-Governor Mayann E. Francis Premier Rodney MacDonald (PC) Federal representation in Canadian Parliament House seats 11 Senate seats 10 Confederation July 1, 1867... The CS Mackay-Bennett was a cable-laying ship based in Halifax, Nova Scotia. ... The Titanics sinking as depicted by artist Willy Stöwer. ...

Intelligence Gathering

Underwater cables, which cannot be kept under constant surveillance, have tempted intelligence-gathering organizations. During the Cold War the US Navy and NSA succeeded in placing wire taps on Soviet underwater communication lines in Operation Ivy Bells. For other uses, see Cold War (disambiguation). ... The United States Navy (USN) is the branch of the United States armed forces responsible for naval operations. ... NSA can stand for: National Security Agency of the USA The British Librarys National Sound Archive This page concerning a three-letter acronym or abbreviation is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Operation Ivy Bells, was a US Navy and NSA mission whose objective was to place wire taps on Soviet underwater communication lines during the Cold War. ...

Notable events

The Newfoundland earthquake of 1929 broke a series of trans-Atlantic cables by triggering a massive undersea avalanche. The sequence of breaks helped scientists chart the progress of the avalanche. The 1929 Grand Banks earthquake occured on November 18 of that year. ...

In July 2005, a portion of the SEA-ME-WE 3 submarine cable located 35 kilometers (21 miles) south of Karachi that provided Pakistan's major outer communications became defective, disrupting almost all of Pakistan's communications with the rest of the world, and affecting approximately 10 million Internet users.^[10][11][12] Ongoing events • 2005 Atlantic and Pacific hurricanes • 2005 Maharashtra floods • 2005 Gujarat Flood • Expo 2005 in Aichi, Japan • Fuel prices • Gomery Comm. ... SEA-ME-WE 3 or South-East Asia - Middle East - Western Europe 3 is a submarine telecommunications cable linking those regions. ...   (Sindhi: , Urdu: ) is the largest city in Pakistan and is the provincial capital of Sindh province. ...

In March, 2007, pirates stole an 11-kilometre section of the T-V-H submarine cable that connected Thailand, Vietnam, and Hong Kong, affecting Vietnam's Internet users with far slower speeds. The thieves attempted to sell the 100 tons of illicit cargo as scrap.^[13] March 2007 is the third month of the year. ... Pirates may refer to: A group of people committing any of these activities: Piracy at sea or on a river/lake. ... T-V-H (Thailand-Vietnam-Hong Kong) is a submarine telecommunications cable system in the South China Sea linking Thailand, Vietnam, and Hong Kong. ...

The 2006 Hengchun earthquake on December 26, 2006 rendered numerous cables near Taiwan inoperable. The 2006 Hengchun earthquake occurred on December 26, 2006 at 12:25 UTC (20:25 local time), with an epicenter off the southwest coast of Taiwan, approximately 22. ... is the 360th day of the year (361st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... The 2006 Hengchun earthquake occurred on December 26, 2006 at 12:25 UTC (20:25 local time), with an epicenter off the southwest coast of Taiwan, approximately 22. ...

The 2008 submarine cable disruption was a series of cable outages, two of the three Suez Canal cables, two disruptions in the Persian Gulf, and one in Malaysia. It caused massive communications disruptions to India and the Middle East.^[14][15] For other uses, see Suez (disambiguation). ... A map showing countries commonly considered to be part of the Middle East The Middle East is a region comprising the lands around the southern and eastern parts of the Mediterranean Sea, a territory that extends from the eastern Mediterranean Sea to the Persian Gulf. ...

Owners and operators of cable-laying ships^[16]

• ACPL
• NSW
• ASN Marine
• Elettra
• FT Marine
• Global Marine Systems Limited
• NTT World Engineering Marine Corporation (NTT-WEM)
• S. B. Submarine Systems
• YIT Primatel Ltd.
• E-MARINE
• IT International Telecom Inc.
• Subsea 7

See also

• List of international submarine communications cables
• List of domestic submarine communications cables
• Transatlantic telegraph cable
• Transatlantic telephone cable
• Optical fibre
• Cable layer (ship)

This is a list of international submarine communications cables and does not include domestic cable systems, such as those on the coastlines of China, Italy and Brazil. ... The first transatlantic telegraph cable crossed the Atlantic Ocean from Foilhommerum, Valentia Island, in western Ireland to Hearts Content, in eastern Newfoundland. ... A transatlantic telephone cable is a submarine communications cable that carries telephone traffic under the Atlantic Ocean. ... Fiber Optic strands An optical fiber in American English or fibre in British English is a transparent thin fiber for transmitting light. ... A cable layer is a deep-sea vessel designed and used to lay underwater cables for telecommunications, electricity, and such. ...

References

External links

• The International Cable Protection Committee -- includes a register of submarine cables worldwide (though not always updated as often as one might hope)
• Submarine Cable Market Overview, November, 2007 -- includes details of many major submarine cable systems
• Timeline of Submarine Communications Cables, 1850-2008
• History of the Atlantic Cable & Submarine Telegraphy - Wire Rope and the Submarine Cable Industry
• France Telecom's Fishermen's/Submarine Cable Information
• Oregon Fisherman's Cable Committee
• Website with comprehensive list of cable landing sites and suppliers globally (contains many duplicates and incomplete data)
• 1939 Article on Laying Submarine Cables
• Mother Earth Mother Board - Wired article by Neal Stephenson about submarine cables
• Nature article - Geomagnetic induction on a transatlantic communications cable
• Hunt, Bruce J. Lord Cable. Europhysics News (2004), Vol. 35 No 6.
• Animations from Alcatel showing how submarine cables are installed and repaired
• Work begins to repair severed net

Maps

• Alcatel Optical Fiber Submarine systems Map, 2007.
• Map and Satellite views of US landing sites for transatlantic cables
• Map and Satellite views of US landing sites for transpacific cables
• Kingfisher Information Service - source of free maps of cable routes in and around the UK/North Sea area