Abstract :
The first public manual exchange was brought into service at Coleman Street, London, in 1879 by the Telephone Company Ltd. The UK´s first public service automatic telephone exchange, a Strowger system exchange manufactured by the Automatic Telephone Manufacturing Company of Liverpool, was opened at Epsom, Surrey, in 1912. This foreshadowed the conversion of the UK telephone network to automatic working and thus was a significant milestone. The basic Strowger system was not suitable for multi-exchange area application and an alternative approach was required. This was referred to as `The Big City Problem´. The solution required translation of the exchange code digits to give routing flexibility over the local network. This gave rise to the register-translator concept; the beginning of the common control switching technique
