A new design was begun between 1941 and 1943 by Captain Arthur Alder, a professor of mathematics at the University of Bern.
The team which designed the machine also included Professors Hugo Hadwiger and Heinrich Emil Weber.
After some modifications, the design was accepted in March 1945, and production of 640 machines began the following month by Zellweger AG.
NEMA was declassified on 9 July 1992, and machines were offered for sale to the public on 4 May 1994.
NEMA uses 10 wheels, of which four are normal electrical rotors with 26 contacts at each end that are scramble wired in a way unique to each rotor type; one is an electrical reflector (like the Enigma's Umkehrwalze) with one set of 26 pairwise cross connected contacts; and the remaining five are "drive wheels", with mechanical cams that control the stepping of the rotors and the reflector.