This cable from Sesimbra, Portugal to Goonhilly, England, was manufactured by Standard Telephones & Cables Ltd. and was owned and operated by the British GPO and the Portuguese CPRM (Companhia Portuguesa Rádio Marconi).
The main cable was laid by CS Monarch (4) and the shore ends by CS Alert (4). This cable was a UK link to SAT-1, the South Africa - Portugal cable, which was laid in 1968 and opened on 18 February 1969. The route of SAT-1 was Melkbosstrand, South Africa - Georgetown, Ascension - Baia da Mordeira, Cape Verde Islands - Santa Cruz, Tenerife - Sesimbra, Portugal.
System length of the Portugal - UK section was 951 nm; it was withdrawn from service in 1992.
The Portuguese medal shown below commemorates the 1969 inauguration of the Sesimbra cable station. In 1973 a radio link connected Sesimbra to the TAT-5 cable station at Conil, Spain.
The obverse shows Zeus and Poseidon. The wording around the edge of the reverse translates as: "From the whole world to the whole world via Portugal," and the centre wording as: "Submarine cable station Sesimbra inaugurated by his excellency the President of the Republic Americo Thomaz 11-8-1969".