Tefag radio headphones

The Tefag radio headphones were produced in the 1920s and 1930s by the German Telephon-Fabrik Berliner AG (of which Tefag is an acronym). The company ran manufacturing operations between 1923-1944, mostly manufacturing cables, telephones, and telecommunications equipment. The enterprise also manufactured loudspeakers and other amplification equipment used in radio broadcasting. In their operating principle, radio headphones are essentially a telephone receiver and are used for the reception of sound by individuals. They were used in the first radio devices (usually in crystal detectors). They work by converting electrical energy into acoustic energy, i.e., audible sonic waves. Early models of such headphones, produced in the inter-war period, are rigid Bakelite cups connected with a wire headband. Manufacturer: Tefag Radio Vertriebs GmbH, 1920s Inv. No.: MIM 392/V-93 Model prepared on the basis of photogrammetric measurements Licence: CC BY-NC-SA (CC Attribution-NonCommercial-ShareAlike)