1. A method for identifying a candidate audio segment from an outbound telephone call, the method comprising the steps of: a) creating a spectrogram of the candidate audio segment; b) creating a candidate binary acoustic fingerprint bitmap of the spectrogram; c) comparing the candidate binary acoustic fingerprint bitmap to at least one known binary acoustic fingerprint bitmap of a known network message; d) if the candidate binary acoustic fingerprint bitmap matches one of said at least one known binary acoustic fingerprint bitmaps within a predetermined threshold, declaring the match; and e) if the candidate binary acoustic fingerprint bitmap does not match one of said at least one known binary acoustic fingerprint bitmaps within the predetermined threshold, using an answering machine detection algorithm to analyze the candidate audio segment.