R E FarrThe author joined the Post Office Engineering Department as an apprentice at Ashford, Kent, in 1943. After transferring to the London headquarters of the Department in 1949, he was involved with various aspects of the development of the UK telecommuncations network for some 30 years. During this period he acquired a wide knowledge of the economic principles of switching centre, network and strategic planning. He subsequently took charge of the Performance Evaluation Section of what is now the Performance Engineering Division of British Telecom Research Laboratories, at Martlesham Heath, in Suffolk. In this post, from which he retired in 1986, he was responsible for a wide range of projects, from coordinating the evaluation of the System X public-network switching system to the evaluation of private networks and PBXs. Read More Read Less