The German navy started using Enigma machines in 1926; it was called "Funkschlüssel C" ("Radio cipher C"). By 15 July 1928, the German Army ("Reichswehr") had introduced their own version of the Enigma—the "Enigma G"; a revised "Enigma I" (with plugboard) appeared in June 1930. The Enigma I used by the German military in the 1930s was a 3-rotor machine. Initially, there were only three rotors labeled "I", "II", and "III", but they could be arranged in any order when placed in the machine. Rejewski identified the rotor permutations by , , and ; the encipherment produced by the rotors altered as each character was encrypted. The rightmost permutation () changed with each character. In addition, there was a plugboard that did some additional scrambling.