Positive Answer Machine Detection

We use Asterisk as the voice server for our mass notification service. We work with many municipalities, and often call large numbers of residents.

Does anyone have any experience with, or suggestions for the most effective method of detecting answering machines, and the methods for leaving voice message on answering machines and cell phones?


I think the best way is to ask to enter one or more digits, a person should be able to enter the confirmation digits, a machine no (for now, who knows the future :wink: ).


Marco Bruni

There is an application within Asterisk and it is called AMD(). The working is based on the pattern of words and the periods of silence. In Holland it is not working that well because we used to say something like “Good afternoon, with John Doe” when we pick up a phone, while in the US (so I was told) people just pick up the phone with “yeah” which is of much help to detect an answering machine that used to start with something like "at this moment all our emloyees are busy etc. etc.

It might be of use, it depends on the quality of the answering machine detection you are looking for.

for what its worth it does not work that well in the US either. after tuning up the timing of the patters of silence etc i found the best you can do is about 85-90% accuracy.

I think the positive interaction like typing back some digits is the only way to approach this if you need high levels of accuracy.