制御装置
In 1961 Plessey merged with the British Ericsson Telephone company and Automatic Telephone and Electric (AT&amp;E) of Liverpool, to become Britain's largest manufacturer of telecommunications equipment, including the majority of the country's crossbar switches. Alongside the Telecommunications Division, three other businesses were set up: Plessey Avionics and Communications, Plessey Radar and Plessey Marine. In 1970, the Command and Control unit was set up at Christchurch, Dorset, which became the centre of the Plessey Defence Systems business. In 1979, a major subsidiary was set up, Plessey Electronic Systems Ltd, which incorporated the three businesses and by 1986 achieved sales of over £500 million and employed 15,000.