Cipher machine

Cipher machine, 'Enigma', wood / metal / Bakelite, Chiffreurmachine Company, Berlin, Germany, 1940. Wehrmacht (German army) type in a dark beige painted metal casing. The top consists of three 1 - 26 numbered rotors, a Bakelite switch with two options, and a keyboard of letters in the configurations: QWERTZUIO, ASDFGHJK, PYXCVBNML the keys are made of metal and black Bakelite with white letters. The display or lamp board above shows same letters, this can be lifted by unscrewing two round nuts located on the sides of the display board to reveal three rows of lamps which light up the letters, three numbered wheels and switching gear. On the front face of the housing is a plug board with connector holes for each letter and ten connector cables which are plugged into various letters. Depressing the key for a given letter causes a signal for that letter to pass through the three rotors and the plug board. This operation causes a cascade of substitutions for the original letter. In this manner a message can be coded that can only be retrieved by being played back through the same sequence of substitutions.