Transmission of precoded numerical message with the R-354 radio set. The message is stored on a film strip (35mm photographic film) with punched holes. The message is transmitted in morse code at a speed of 250 groups per minute (= 1250 characters per minute).
The sound comes from a shortwave receiver which was tuned on the transmitting frequency.
Detaljerad info: www.cryptomuseum.com/spy/r354/index.htm