A method and system for detecting a dual tone in a composite signal having
first and second components including means for separating the composite
signal into its first and second components, means for estimating power
of the separated first and second components, means for determining
frequency of the separated first and second components, and means for
comparing the power and frequency of the first and second components to
at least one of a plurality of respective power and frequency thresholds
to determine whether the composite signal comprises a dual tone.