Abstract: A voice detection circuit uses normal and customary signal peaks and pauses in speech to distinguish voice from mere noise. The voice detection circuit includes an audio input device for receiving an audio signal and comparing it to a threshold, and a detector for generating the VOX output signal responsive to the presence of the peaks and pauses in the audio signal which rise above the threshold. The switch is actuated upon the VOX output signal indicating that the audio signal includes selected patterns of peaks and pauses and thus comprises voice signals. Illustratively, the threshold may be varied in accordance with the input signals when the voice detection circuit indicates that the input audio signals do not comprise voice signals.