There is a total of thirty six 52 way and eighteen 104 way cableforms connecting together the Letchworth Enigmas. This does not include various other control and signal cableforms. Nor does it include the wiring behind each Letchworth Enigma. In all around twelve miles of wire was used. Because of the considerable amount of work involved the manufacture of these cableforms started midway through the year 2000. They were completed towards the end of 2003.

Above:- Samples of early new cableforms

There are 54 cableforms used to connect the 36 Letchworth Enigmas to the rest of the machine. They are made up of 

  • 18 Enigma pairs to 4 Jacks on the rear of the machine. Each is a 104 way cable terminating with an input and output Jack for each of 2 Enigmas

  • 36 Enigma to Plugboard (Umkehrwalze) on the left end of the machine. Each is a 52 way cable, 26 ‘go’ and 26 ‘return’.

A significant number of these cableforms, less terminations, were test fitted to the machine to ensure that lengths and routes were correct.

It is just possible to see one of each type of cable in the image above. They relate to a pair of Enigmas in the middle of the top bank. Just one 52 way cable can be seen leaving the top of an Enigma position where it travels down the frame upright nearest to us and then around in a loop where it will plug into the rear of a plugboard which is at this stage yet to be fitted. A 104 way cable can be seen at the bottom of the Enigmas. This travels along the horizontal bar, around the Jack Frame hinge and across the Jack frame where the 4 Jacks are fitted. All 54 Letchworth Enigma cableforms with their terminations fitted were later fitted to the machine.

Below are the large number of cableforms laced and ready for the termination phase. This work was carried out at Harlow by Chris Carter, Chris Tarry and Ken Darton with help from others from time to time. This work has taken place, typically taking three days per week, over a three year period. The magnitude of the effort involved can now be appreciated.

Menu Cables and Cross And Connect Units

Cableforms Installed

Cable Terminations

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