Plugboard

British codebreakers succeeded in breaking these machines, which lacked a plugboard.sfn Enigma were also used by diplomatic services.

Current flowed from the battery (1) through a depressed bi-directional keyboard switch (2) to the plugboard (3).

Current flowed from the keyboard through the plugboard, and proceeded to the entry-rotor or Eintrittswalze.

During the Spanish Civil War the Italian Navy used the K model of the commercial Enigma without a plugboard; this was solved by Knox in 1937.

During World War II, codebooks were only used each day to set up the rotors, their ring settings and the plugboard.

For a message to be correctly encrypted and decrypted, both sender and receiver had to configure their Enigma in the same way; rotor selection and order, starting position and plugboard connections must be identical.

Keys were easily changed by changing the rotor disks and the plugboard wires.

The addition of a control panel (plugboard) to his 1906 Type I Tabulator allowed it to do different jobs without having to be physically rebuilt.

The Japanese are said to have obtained an Enigma machine in 1937, although it is debated whether they were given it by the Germans or bought a commercial version which apart from the plugboard and internal wirings, was the German Heer/Luftwaffe machine.

The plugboard contributed more cryptographic strength than an extra rotor.

Uhr The Enigma Uhr attachment In 1944, the Luftwaffe introduced a plugboard switch, called the Uhr (clock), a small box containing a switch with 40 positions.