[Asterisk-Users] Answering Machine Detection

[Alastair Maw]

On 27/10/03 21:57, DUSTIN WILDES wrote:
> Does anyone have any recommendations on implementing Answering
> Machine detection for call generation programs?

There's obviously no nice way of doing this.
If you're doing telemarketing, and you're playing pre-recorded audio, 
which of course is a nasty thing to do, the algorithm is something like:

1. Dial out.
2. Wait for answer.
3. Start playing audio.
4. If you hear something that sounds like a beep, either hang up
    and try again later, or stop the audio, pause for two seconds
    and start playing it again.
5. Hang up when finished playing audio.

Step 4 is accomplished by doing a FFT on the incoming audio into 
frequency buckets and taking a rolling average of the mean and standard 
deviation, such that you can detect when a fixed monotone beep occurs at 
the other end.


If you don't want to play audio files and wait for beeps, and want to 
connect real humans to each other, then there's no decent way to do 
this, as the only difference between humans and arbitrary answering 
machines is that the answering machines give you a beep prompt to record 
your message.

Regards,

-- 
Alastair Maw