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Transatlantic telephone cable

A transatlantic telephone cable is a submarine communications cable that carries telephone traffic under the Atlantic Ocean.

While the first transatlantic telegraph cable had been laid in 1858 (Cyrus Field), it had only operated for a month. Attempts in 1865 and 1866 were more successful but although a telephone cable was discussed from the 1920s it needed a number of technological advances that did not arrive until the 1940s to be practical. Until TAT-1 the transatlantic telephone service was radio-based, started in 1927 it cost £9 for three minutes and took 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 of the recent systems have used fiber optic transmission, and a self-healing ring[?] topology.

Cable Name	Date(s)	Initial No. of channels	Final No. of channels	One End	Other End
TAT-1	1956-1978	36	48	Scotland	Newfoundland
TAT-2	1959-1982	48	72	France	Newfoundland
TAT-3	1963-1986	138	276	England	New Jersey
TAT-4	1965-1987	138	345	France	New Jersey
TAT-5	1970-1993	845	2112	Rhode Island	Spain
TAT-6	1976-1994	4,000	10,000	Rhode Island	France
TAT-7	1978-1994	4,000	10,500	New Jersey	England
TAT-8*	1988	40,000	-	USA	France
TAT-9	1992	80,000	-	USA	Spain
TAT-10	1992	2 x 565Mb/s	-	USA	Germany
TAT-11	1993	2 x 565Mb/s	-	USA	France
TAT-12/13	1996	2 x 5Gb/s	-
TAT-14	2000	16 x 10Gb/s	-	USA	England
CANTAT-1	1961-1986	80	-	Newfoundland	Scotland
CANTAT-2	1974-1992	1,840	-	Nova Scotia	England
CANTAT-3	1994	2 x 2.5Gb/s		Canada	Europe
PTAT-1	1990	3 x 140Mb/s?		US-Bermuda	Ireland-UK

* first fibre optic cable.

TAT are almost all north Atlantic cables, there are a number of non-TAT cables further south - SAT-2[?], ATLANTIS-2[?], COLUMBUS III[?] etc.

All TAT cables are joint ventures between AT&T and some European telco, e.g. British Telecom. CANTAT are Canadian Transatlantic Telephone cables. A private competitor during the 1990s was Global Crossing.

External links

Submarine Cables of the World: Atlantic Region (http://www.iscpc.org/cabledb/atlan_page.htm)
Aronsson's Telecom History Timeline (http://aronsson.se/hist)

All Wikipedia text is available under the terms of the GNU Free Documentation License

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