Signals from Telecom Tower. Computer artwork of Telecom Tower in London, showing microwave signals radiating from its top aerial. Towers like this form the links in modern telecommunications networks relaying telephone, telex and data communications. The rounded microwave aerials seen, point towards other towers which may be many kilometres away. At the time of completion in 1966, Telecom Tower (formerly known as the Post Office Tower) was Britain's tallest building at 189 metres high. It can process 150,000 simultaneous telephone conversations and over 40 television channels.