A system receives an audio stream from an application, and performs signal analysis on the audio stream to compute (on sound and silence) a sequence of events. The sequence of events identifies a pattern comprised of at least two of sound, silence, frequency, magnitude, duration, tone, and Dual Tone Multi Frequency (DTMF). The pattern matches a similar pattern of at least two of sound, silence, frequency, magnitude, duration, tone, and DTMF, and the signal analysis is performed on sound and silence within the audio stream. The similar pattern is associated with at least one of an automated device or human answering the call. The system determines whether the sequence of events indicates the phone call is answered by the automated device or the human, based on rules in a heuristic engine and/or a known audio print from a library of known audio prints.