Improvements in and relating to phonographs and like apparatus
DE336577C
Device for automatic switching on and off of a circuit when the occurrence and cessation of speech currents or other electrical vibrations, especially e for parlographs, dictaphones, telephones and the like. like
DE368676C
Method for acoustic or electrical reproduction of phonographically recorded signals, characters or the like.
DE336116C
Locking device for phonographs and similar devices to prevent the cylinder from being pushed on or taken off in the working positions of the sound boxes
