AMD()

Since 1.4.0 Applications

Attempt to detect answering machines.

Last reviewed 2026-04-14

AMD([initialSilence,greeting,afterGreetingSilence,totalAnalysisTime,miniumWordLength,betweenWordSilence,maximumNumberOfWords,silenceThreshold,maximumWordLength,audioFile])

Dialplan Builder -- build your AMD() command

initialSilence (optional)

Is maximum initial silence duration before greeting.

greeting (optional)

is the maximum length of a greeting.

afterGreetingSilence (optional)

Is the silence after detecting a greeting.

totalAnalysisTime (optional)

Is the maximum time allowed for the algorithm

miniumWordLength (optional)

Is the minimum duration of Voice considered to be a word

betweenWordSilence (optional)

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

maximumNumberOfWords (optional)

Is the maximum number of words in a greeting

silenceThreshold (optional)

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

maximumWordLength (optional)

Is the maximum duration of a word to accept.

audioFile (optional)

Is an audio file to play to the caller while AMD is in progress.

Full arguments reference

initialSilence - Is maximum initial silence duration before greeting.
greeting - is the maximum length of a greeting.
afterGreetingSilence - Is the silence after detecting a greeting.
totalAnalysisTime - Is the maximum time allowed for the algorithm
miniumWordLength - Is the minimum duration of Voice considered to be a word
betweenWordSilence - 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
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 a word to accept.
audioFile - Is an audio file to play to the caller while AMD is in progress.

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 the calling AMD with parameters.

This application sets the following channel variables:

AMDSTATUS - This is the status of the answering machine detection
- MACHINE
- HUMAN
- NOTSURE
- HANGUP
AMDCAUSE - Indicates the cause that led to the conclusion
- TOOLONG - Total Time.
- INITIALSILENCE - Silence Duration - Initial Silence.
- HUMAN - Silence Duration - afterGreetingSilence.
- LONGGREETING - Voice Duration - Greeting.
- MAXWORDLENGTH - Word Length - max length of a single word.
- MAXWORDS - Word Count - maximum number of words.

Arguments

initialSilence - Is maximum initial silence duration before greeting.
greeting - is the maximum length of a greeting.
afterGreetingSilence - Is the silence after detecting a greeting.
totalAnalysisTime - Is the maximum time allowed for the algorithm
miniumWordLength - Is the minimum duration of Voice considered to be a word
betweenWordSilence - 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
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 a word to accept.
audioFile - Is an audio file to play to the caller while AMD is in progress.

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