The computers that won the war: Bletchley Park's codebreaking equipment is rebuilt


Tunny in Action - 1

Source:  Robert Dowell, TNMOC

Tunny in Action - 1

During the war, the Tunny operator would use the information provided by the codebreakers to set the machine in exactly the same way as the German operator had done when the message was transmitted. This would be different for every message. The settings of the Lorenz machine were entered by inserting white pegs into the respective jack fields located in the centre of the rack.


The Tunny Gallery, opened at The National Museum of Computing at Bletchley Park on 26 May 2011, tells the incredible story of the interception and decryption of German High Command radio teleprinter messages during World War Two. The gallery shows the entire wartime code-breaking process from intercept to decrypt and recognises the remarkable achievements of the men and women who contributed to the process in the 1940s. The centrepiece of the gallery is a fully functioning rebuild of a Tunny machine that produced the final decrypts of enciphered communications of the German High Command. The original Tunny, a British re-engineering of the then-unseen German Lorenz S42 cipher machine, was completed in 1942.

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