Answer Machine Detection
When turned on the answer machine detection (AMD) algorithm monitors incoming audio. Based on the energy level of the incoming audio and configuration the audio is classified as either background or voice energy. The duration of the background or voice energy is measured and events generated back to CCXML to report current detection status. The AMD will monitor the audio until either a termination condition has been met or the maximum run time has been reached.
If the energy detected is voice and is stable (close in power to the previous energy) this energy is a candidate for being a beep. Provided the beep energy is on long enough (based on the configuration) this will lead to beep related events.
The AMD monitoring is purely used to report the current interpreted status of the incoming audio energy. The CCXML application then interprets these events based on its design (eg recording message after a beep, playing different dialogs based on human/machine)
Fax Machine Detection
When turned on the fax machine detection algorithm monitors incoming audio. The algorithm is looking for either 1100Hz or 2100Hz fax tones. If either tone is detected for the required duration then an event is sent to CCXML.
The 1100Hz tone must be present for at least 420ms to generate an event. The 2100Hz tone must be present for at least 2580ms to generate an event.
Call Progess Detection operation is explained in the following sections: