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AMD() - [app_amd]

Synopsis

Attempt to detect answering machines.

Since

1.4.0

Description

This application attempts to detect answering machines at the beginning of outbound calls. Simply call this application after the call has been answered (outbound only, of course).

When loaded, AMD reads amd.conf and uses the parameters specified as default values. Those default values get overwritten when calling AMD with parameters. All durations are specified in milliseconds.

This application sets the following channel variables, unless the detection could not be performed at all, in which case both variables are set to the empty string:

  • AMDSTATUS - This is the status of the answering machine detection

    • MACHINE

    • HUMAN

    • NOTSURE

    • HANGUP

  • AMDCAUSE - Indicates the cause that led to the conclusion. The measurement which triggered it, and for most causes the parameter value it breached, are appended to the cause name, separated by '-'.

    • TOOLONG - Total Time.

    • NOAUDIODATA - Total Time.

    • INITIALSILENCE - Silence Duration - initialSilence.

    • HUMAN - Silence Duration - afterGreetingSilence.

    • LONGGREETING - Voice Duration - greeting.

    • MAXWORDLENGTH - Consecutive Voice Duration.

    • MAXWORDS - Word Count - maximumNumberOfWords.

Syntax

AMD([initialSilence,[greeting,[afterGreetingSilence,[totalAnalysisTime,[minimumWordLength,[betweenWordsSilence,[maximumNumberOfWords,[silenceThreshold,[maximumWordLength,[audioFile]]]]]]]]]])
Arguments

  • initialSilence - Is maximum initial silence duration before greeting.
    If this is exceeded, the result is detection as a MACHINE

  • greeting - is the maximum length of a greeting.
    If this is exceeded, the result is detection as a MACHINE

  • afterGreetingSilence - Is the silence after detecting a greeting.
    If this is exceeded, the result is detection as a HUMAN

  • totalAnalysisTime - Is the maximum time allowed for the algorithm
    to decide on whether the audio represents a HUMAN, or a MACHINE

  • minimumWordLength - Is the minimum duration of Voice considered to be a word

  • betweenWordsSilence - Is the minimum duration of silence after a word to consider the audio that follows to be a new word

  • maximumNumberOfWords - Is the maximum number of words in a greeting
    If this is exceeded, then the result is detection as a MACHINE

  • silenceThreshold - What is the average level of noise from 0 to 32767 which if not exceeded, should be considered silence?

  • maximumWordLength - Is the maximum duration of continuous voice to accept as a single word.
    If exceeded, then the result is detection as a MACHINE

  • audioFile - Is an audio file to play to the caller while AMD is in progress.
    By default, no audio file is played.
    If an audio file is configured in amd.conf, then that file will be used if one is not specified here. That file may be overridden by this argument.

See Also

Generated Version

This documentation was generated from Asterisk branch 20 using version GIT