Audio playback unit

Claim 1

AUDIO PLAYBACK EQUIPMENT COMPRISING: A FILM CYLINDER HAVING FIXED AROUND ITS PERIPHERY A PLURALITY OF SOUND TRACKS CONTAINING OPTICAL SIGNALS REPRESENTING AUDIO MESSAGES CAPABLE OF BEING TRANSDUCED INTO AUDIBLE FORM, EACH OF SAID OPTICAL SIGNAL MESSAGES ENDING AT A PREDETERMINED POINT ON ITS ASSOCIATED TRACK, MEANS FOR DEVELOPING AN ELECTRICAL REFERENCE SIGNAL INDICATING THE END OF SAID SOUND TRACKS, MEANS FOR ROTATING SAID CYLINDER AND THEREBY ROTATING ALL SAID TRACKS SIMULTANEOUSLY, MEANS INCLUDING A PLURALITY OF STATIONARY OPTICAL TRANSDUCERS RESPECTIVELY DISPOSED ADJACENT SAID TRACKS, FOR PROVIDING, DURING ROTATION OF SAID CYLINDER IN THE SAME DIRECTION, SIMULTANEOUSLY OCCURRING, RESPECTIVE OUTPUTS REPRESENTING A CONVERSION OF SAID OPTICAL SIGNALS INTO ELECTRICAL SOUND SIGNALS, MEANS FOR AMPLIFYING SAID ELECTRICAL SOUND SIGNALS, MEANS FOR TRANSDUCING SAID AMPLIFIED ELECTRICAL SOUND SIGNALS INTO AUDIBLE MESSAGES, AND AUTOMATIC MEANS USING SAID ELECTRICAL REFERENCE SIGNAL AND INCLUDING A SWITCHING CIRCUIT FOR SELECTING ANY DESIRED ONE OF SAID SIMULTANEOUSLY OCCURRING OPTICAL TRANSDUCER OUTPUTS WHILE SAID CYLINDER IS ROTATING IN SAID SAME DIRECTION AND WHEN SAID SWITCHING CIRCUIT OPERATIVELY ASSOCIATED WITH ONE END OF SAID MESSAGE ENDING POINTS AND TACITLY SWITCHING THE CORRESPONDING ELECTRICAL SOUND SIGNALS TO SAID AMPLIFYING MEANS FOR PLAYBACK IN AUDIO FORM BY SAID TRANSDUCING MEANS.