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Alec Harley Reeves Reeves, Alec Harley (1902-1971)

Alec Reeves devised Pulse-Code Modulation, the first digital coding system, which liberated bandwidth.

Reeves, a natural tinkerer, grew up in the Home Counties. He glided through his electrical engineering degree to take a job developing long-wave transatlantic radio communications in the 1920s. He also helped develop short-wave and microwave radio systems.

Reeves became acutely aware of the shortcomings of analogue communication and this led him to develop Pulse-Code Modulation in 1937. It was a long time before the work was fully appreciated, but in 1969 he received the CBE - and a postal stamp commemorating PCM was issued.

Reeves was peace-loving and reluctant to work on offensive weapons, so during the Second World War he developed pinpoint bombing aids, which helped reduce civilian casualties, for which he received an OBE.

He became head of research on electronic switching systems at Standard Telecommunication Laboratories until he retired. Reeves dedicated his private life to helping others, particularly in youth and community projects and rehabilitating prisoners.

fun and games

Can you beat our games? Explode equipment to see what's inside, hear the changing sounds of telecommunications, see how telecommunications designs have changed over time or send an e-postacard.

what's on

The UK's first permanent gallery dedicated to the history of information and communication technologies opens in the new Information Age gallery at London’s Science Museum.

audio history

Take a trip down memory lane with extracts of the interviews which have been recorded as part of the Connected Earth oral history programme.

featured story

100 years of automatic switching!
In 1912 the GPO installed Britain's first automatic telephone exchange in Epsom.

Discover the early days of the telephone...