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.
* 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.
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
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