Abstract: A digital voice switch for detecting voice PCM samples in the presence of noise samples is disclosed. The switch includes a digital variable threshold generating means which adapts the threshold level to changes in the noise level. Advantage is taken of the fact that, over a given interval of time T, speech will occur as random talk spurts separated by periods of silence, while noise (Gaussian distributed) will be continuous. This difference between speech and noise makes it possible to detect the noise level with respect to the voice switch threshold level.