Cypher Machines Typex Mk III cypher machine for field use, late 1930s

Cypher Machines Typex Mk III cypher machine for field use, late 1930s. The British Typex cypher machine was based on the German Enigma machine. In 1928 the British government bought two commercial Enigmas and commissioned Creed & Company to manufacture an Enigma-type machine. By 1936, they had produced an electro-mechanical cypher machine of their own which became known as Ôthe RAF Enigma with Type X attachmentsÕ, and subsequently 'Typex'. Impulses are transmitted through 5 drums or wheels, arranged in a pre-determined order. A message is typed with the left hand whilst turning the handle with the right, achieving 20 words a minute. Cypher, or plain text, is printed onto paper tape, to be transcribed into a communication system. It is thought that the Germans were unable to read messages encyphered by Typex. ©SSPL/Science Museum