Some three months later, in September 1940, they returned to work covertly in unoccupied southern, Vichy France. Rejewski's cover was as "Pierre Ranaud", a "lycée" professor from Nantes. A radio-intelligence station was set up at the Château des Fouzes, code-named "Cadix", near Uzès. "Cadix" began operations on 1 October. Rejewski and his colleagues solved German telegraph ciphers, and also the Swiss version of the Enigma machine (which had no plugboard). Rejewski may have had little or no involvement in working on German Enigma at "Cadix".