Alec Reeves was born on 10 March 1902 in Redhill, Surrey. His father was a surveyor to the Royal Geographical Society and had met Livingstone, Stanley and Gordon of Khartoum. After graduating in engineering from Imperial College, London, Alec joined International Western Electric, a radio equipment manufacturer which was later taken over by International Telephone and Telegraph (ITT).
In 1925 Reeves went to the ITT laboratories in Paris, where he helped build the first cross-channel radio-telephone links. He also patented his Pulse Code Modulation system, which dealt with the problem of interference by turning analogue signals, such as sound, into digital signals in the form of on-off pulses.
On the outbreak of war, Reeves managed to escape from France on a coal boat. Although a pacifist, he believed that Hitler needed to be defeated and joined the Telecommunications Research Establishment (TRE) at Malvern for war work. It was here that he developed the Oboe Navigation System which was to have such an impact on the outcome of the war.
Reeves returned to ITT after the war, pioneering the use of semiconductors. He was also one of the first people to look at the use of light for communications, inspiring the development of the first practical optical fibre system. He has been described as 'the father of the information age'.