6 of 6Image
The wiring at the back of the Tunny machine
The back of the Tunny machine took two people 18 months' solid work to rewire.
"That was an absolute bastard of a job," said Whetter. "It was a labour of love."
Each of the uniselectors had 25 outputs, while each switch had over 120 connectors.
Further details on how to visit the Tunny Gallery can be found at the National Museum of Computing's website.
Photo credit: Bletchley Park
Get the latest technology news and analysis, blogs and reviews delivered directly to your inbox with ZDNet UK's newsletters.