Patent ID: 6115464
Filing Date: 2000-09-05
Classification: H04Q

Abstract:
A method of distinguishing equipment-directed dual tone multifrequency (DTMF) signals intended for processing from spurious DTMF noise comprising steps of:monitoring a telecommunications line connected to receive signals from a remote device capable of generating DTMF signals;detecting a first signal received via said telecommunications line, said first signal having a first signal component indicative of a DTMF signal and having a second signal component having frequencies unrelated to DTMF frequencies for generating said DTMF signals;analyzing said second signal component to a substantial exclusion of said first signal component to determine whether a signal level that is representative of said second signal component exceeds a predetermined threshold level; andbased upon said analysis of said second signal, designating said first signal as one of spurious DTMF noise or an equipment-directed DTMF signal intended for processing.