Abstract: A multiple tone signaling device provides a piezoelectric transducer, first, second and third oscillator circuits, a first input terminal for enabling either or both of the first and second oscillator circuits, circuitry coupling the third oscillator circuit to the first and second oscillator circuits for disabling either the first or second oscillator circuits in response thereto, and a second input terminal coupled to the third oscillator circuit for allowing control of the output of said third oscillator circuit.

Abstract: A remote alarm system provides a transmitter having an audio frequency signal generator circuit, a modulator circuit forming a current source modulated by the audio frequency signal and a radio frequency oscillator circuit modulated by the current source, and a receiver having a super-regenerative detector, an amplifier connected thereto, a notch filter for selectively filtering the audio frequency signal, an alternating current rectifier for rectifying the audio frequency signal, a delay circuit for delaying activation of an alarm signal until a signal from the rectifier circuit is present for a predetermined amount of time and for determining a period of time for activation of an alarm signal, and an alarm means for generating an alarm signal in response to the output of the delay circuit.