Transatlantic communications cable

A transatlantic telecommunications cable is a submarine communications cable running under the Atlantic Ocean. All modern cables use fibre optic technology.

Most such cables follow the great circle route from London to New York City because of the high-speed requirements of international financial transactions. Financial trading firms spend billions of dollars annually to get an edge on trading [1].

This route provides convenient well-supported landings near Halifax (or Moncton), St. John's, Iceland (or Belfast) and Dublin. Many cables are monitored and controlled from such central locations rather than from the endpoints, for quicker response to problems, and because it's cheaper to hire qualified people in these less expensive locations. Iceland, furthermore, has great advantages [2] for communications companies as they are effectively immune from defamation lawsuits for disseminating any adverse information about public events or companies or figures, which is a key driver of day trading and arbitrage activity. Such intermediary points on the great circle route are expected to play an increasingly prominent role in these activities, if only because trading signals originating there reach both London and New York faster than any signal originating in one centre trying to reach the other.

When the first transatlantic telegraph cable was laid in 1858 by businessman Cyrus West Field, it operated for only a month; subsequent attempts in 1865 and 1866 were more successful. 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, Scotland and Clarenville, Newfoundland between 1955 and 1956 by the cable ship Monarch. 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. TAT-1 was finally retired in 1978.

There have been a succession of newer transatlantic cable systems. All recent systems have used fiber optic transmission, and a self-healing ring topology. Late in the 20th century, communications satellites 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 speed - the 2012 generation of cables drop the transatlantic latency to under 60 milliseconds, according to Hibernia Atlantic [3], deploying such a cable that year. [4] [5]

Cable Name	Date(s) in service	Type	Initial No. of channels	Final No. of channels	Western end	Eastern end
TAT-1	1956–1978	Galvanic	36	48	Newfoundland	United Kingdom
TAT-2	1959–1982	Galvanic	48	72	Newfoundland	France
TAT-3	1963–1986	Galvanic	138	276	New Jersey	United Kingdom
TAT-4	1965–1987	Galvanic	138	345	New Jersey	France
TAT-5	1970–1993	Galvanic	845	2112	Rhode Island	Spain
TAT-6	1976–1994	Galvanic	4,000	10,000	Rhode Island	France
TAT-7	1978–1994	Galvanic	4,000	10,500	New Jersey	United Kingdom
TAT-8*	1988–2002	Fiber-optic	40,000	-	USA	United Kingdom, France
TAT-9	1992–2004	Fiber-optic	80,000	-	USA, Nova Scotia	Spain, France, United Kingdom
TAT-10	1992–2003	Fiber-optic	2 × 565 Mbit/s	-	USA	Germany
TAT-11	1993–2003	Fiber-optic	2 × 565 Mbit/s	-	USA	France
TAT-12/13	1996–2008	Fiber-optic	12 × 2.5 Gbit/s	-	USA × 2	United Kingdom, France
TAT-14	2000–	Fiber-optic	3.2 Tbit/s	-	USA × 2	United Kingdom, France, Netherlands, Germany, Denmark
CANTAT-1	1961–1986	Galvanic	80	-	Newfoundland	United Kingdom
CANTAT-2	1974–1992	Galvanic	1,840	-	Nova Scotia	United Kingdom
CANTAT-3	1994–	Fiber-optic	2 × 2.5 Gbit/s		Nova Scotia	Iceland, Faroe Islands, United Kingdom, Denmark, Germany
PTAT-1	1989–2004	Fiber-optic	3 × 140 Mbit/s?		New Jersey & Bermuda	Ireland & United Kingdom

* first fiber optic cable.

The TAT series of cables constitute a large percentage of all North Atlantic cables. All TAT cables are consortia joint ventures between a number of telecommunications companies, e.g. British Telecom. CANTAT are transatlantic telephone cables terminating in Canada rather than the USA. There are a number of private non-TAT cables.

Cable name	Date(s)	Nominal Capacity	Latency (ms)	Landings	Owner
Gemini (decommissioned)	1998		under 100ms		Cable & Wireless
Apollo	2002	3.2 Tbit/s	under 100ms		Cable & Wireless
AC-1	1998	120 Gbit/s	65ms [6]		Global Crossing
Yellow/AC-2	2000	640 Gbit/s	under 100ms		Level 3 Communications
FLAG Atlantic	2000		under 100ms		Reliance Communications
VSNL Transatlantic	2001	5.1 Tbit/s	under 100ms		sold by Tyco to VSNL in 2005
Hibernia Atlantic	2001	320 Gbit/s	under 70ms		CVC Acquisition Company
Emerald Express	2012 (scheduled)	6 × 10 Tbit/s (six pairs 100x100 Gbit/s)	under 70ms	Moncton, St. John's, Iceland, Belfast, Dublin	Emerald Atlantis
Hibernia Atlantic	2012 (scheduled)	unknown (four strand)	59ms [7]	Herring Cove (near Halifax)	CVC Acquisition Company

See also

• Cable layer

External links

• Hayes, Jeremiah (September 2008). "A history of transatlantic cables". IEEE Communications 46 (9): 42–48. doi:10.1109/MCOM.2008.4623705. 
• Aronsson's Telecom History Timeline
• Timeline of Submarine Communications Cables, 1850–2008
• Submarine Cable Landings Worldwide