Hagelin M-209

The M-209 enciphered US Army traffic from 1942: six pinwheels of 26 to 17 letters, a drum of 27 bars with two lugs each. The pins that act stand 15 to 10 letters past the windows; the bars they kick set how far a reversed alphabet slides. Key lists gave pins, lugs and a 26-letter check, reproduced here for both manuals and a 1943 division’s list.

• War Department, TM 11-380, Converter M-209 (27 April 1942)
• War Department, TM 11-380 (17 March 1944), par. 15b(3); NSA Doc Ref ID A67854
• Signal Operation Instructions, 84th Infantry Division, July 1943