first trans-Atlantic telephone cable

TAT-1 (Transatlantic No. 1) was the first submarine transatlantic telephone cable system. It was laid between Oban, Scotland and Clarenville, Newfoundland.[1] Two cables were laid between 1955 and 1956. One cable for each direction.[1] It was inaugurated on September 25, 1956.[2] The cable was able to carry 35 simultaneous telephone calls.[3] A 36th channel was used to carry up to 22 telegraph lines.[3]


The first transatlantic telegraph cable had been laid in 1858 (see Cyrus West Field).[4] It only operated for a month, but was replaced with a successful connection in 1866.[4] A radio-based transatlantic telephone service was started in 1927. It charged £9 for three minutes.[5] A telephone cable was discussed at that time. But it was not practical until a number of technological advances arrived in the 1940s.

The developments that made TAT-1 possible were coaxial cable, polyethylene insulation, very reliable vacuum tubes for the submerged repeaters and an improvement in carrier equipment. Transistors were not used, being a recent invention of unknown longevity.


  1. 1.0 1.1 "Specimen of the first transatlantic telephone cable, 1956". The Science Museum. Retrieved 4 June 2015.
  2. Bill Burns. "History of the Atlantic Cable & Undersea Communications". Atlantic-Cable.com. Retrieved 4 June 2015.
  3. 3.0 3.1 Bill Ray (14 October 2013). "TAT-1: Call the cable guy, all I see is a beautiful beach". The Register. Retrieved 4 June 2015.
  4. 4.0 4.1 "First transatlantic telegraph cable completed". HIstory.com. A&E Television Networks, LLC. Retrieved 4 June 2015.
  5. "Inside the Science Museum". Sciencemuseum.org. Retrieved 4 June 2015.