TAT-12/13

TAT-12/13 is a ring cable system consisting of the 12th and 13th consortia transatlantic telephone cables, in operation from 1996, initially carrying 2 × 5 Gbit/s.
This was the first TAT cable to use a ring structure, involving two stretches of cable across the ocean floor, which explains why two numbers were used. All later cables also use a ring structure, but only use one number. The cable connected between Long Island, USA; Green Hill, Rhode Island, USA; Porthcurno, UK; Bude, UK; and Penmarch, France.
The cable was constructed for US$740 million and was supplied jointly by AT&T Submarine Systems, Inc, STC Submarine Systems and Alcatel Submarcom. Ring switching equipment was provided by the Toshiba Corporation in each of the four cable stations.
The cables in this system were the first on the trans-Atlantic route to make use of erbium-doped fiber amplifiers.
The TAT-12/13 consortia removed the cable from normal commercial service on 31 December 2008.