73113108
Jan 19, 1977
Dec 5, 1978
ELECTRONIC APPARATUS-NAMELY, SHUT-OFF UNITS, CLOCK/TIMERS, MULTISPEAKER/MULTI-SOURCE SELECTORS, INPUT SELECTORS, AUDIO MIXERS, SOUND-ACTIVATED CONTROLLERS, AUDIO COMPRESSORS, REMOTE SPEAKER TRANSMITTERS AND RECEIVERS, PREAMPLIFIERS AND AUDIO LEVEL INDICATORS
Electrical and Scientific Apparatus