Transatlantic telephone cable

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A transatlantic telephone cable is a submarine communications cable that carries telephone traffic under the Atlantic Ocean between North America and Europe.

When the first transatlantic telegraph cable was laid in 1858 by businessman Cyrus 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. During this period the transatlantic telephone service was radio-based; starting in 1927 it cost £9 (or roughly $16 USD) for three minutes and handled around 2000 calls a year.

TAT-1 (Transatlantic No. 1) was the first submarine transatlantic telephone cable system. It was laid between Gallanach Bay, near Oban, Scotland and Clarenville, Newfoundland between 1955 and 1956. It was inaugurated on September 25 1956, initially carrying 36 telephone channels.

Opened on September 25 1956, in the first 24 hours of public service there were 588 London-US 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. Communications satellites lost most of their North Atlantic telephone traffic to these low cost, high capacity cables.

Cable Name	Date(s)	Type	Initial No. of channels	Final No. of channels	Western end	Eastern end
TAT-1	1956-1978	Galvanic	36	48	Newfoundland	Scotland
TAT-2	1959-1982	Galvanic	48	72	Newfoundland	France
TAT-3	1963-1986	Galvanic	138	276	New Jersey	England
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	England
TAT-8*	1988-2002	Fiber-optic	40,000	-	USA	France
TAT-9	1992-2004	Fiber-optic	80,000	-	USA	Spain
TAT-10	1992-2003	Fiber-optic	2 x 565 Mbit/s	-	USA	Germany
TAT-11	1993-2003	Fiber-optic	2 x 565 Mbit/s	-	USA	France
TAT-12/13	1996	Fiber-optic	12 x 2.5 Gbit/s	-	USA x 2	GB, FR
TAT-14	2000	Fiber-optic	64 x 10 Gbit/s	-	USA x 2	GB, FR, NL, D, DK
CANTAT-1	1961-1986	Fiber-optic	80	-	Newfoundland	Scotland
CANTAT-2	1974-1992	Fiber-optic	1,840	-	Nova Scotia	England
CANTAT-3	1994	Fiber-optic	2 x 2.5 Gbit/s		Nova Scotia	Europe
PTAT-1	1989	Fiber-optic	3 x 140 Mbit/s?		US-Bermuda	Ireland-UK

* 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)	Owner
Gemini	1998	Cable and Wireless
Apollo	2002	Cable and Wireless
AC-1	1998	Global Crossing
Yellow	2000	Level 3
FLAG Atlantic	2000	FLAG (Fiber Optic Link around the Globe) Telecom
TGN Atlantic	2001	sold by Tyco in 2005
Hibernia Atlantic	2001	CVC Acquisition Company