[asterisk-dev] Call Detection

Nir Simionovich nir.simionovich at gmail.com
Sat Jan 24 16:46:48 CST 2009

Hi David,

   What you are referring to is a power-dialer with Answering Machine
detection capabilities. Having developed one, I'm very much unsure that 
reaching an accuracy of 95% is possible.

   The main reason is that depending on your country and termination 
provider, your mileage will vary on the MachineDetect (AMD) application. 
The same applies to the BackgroundDetect application - so in other 
words, the maximum accuracy I ever reached was around the 75%-80%.

   Now, in terms of the actual solution, it all depends on your dialer
implementation. For example, the dialer that I developed was able to do 
that as it was utilizing a specific manner of operation, I'm not 
familiar with yours, so I can't comment specifically. In any case, both 
detection applications require that your channel be up and established, 
prior to the detection process.

   For more information, you may contact me off-list.


David Phillips wrote:
> Hi all,
> We have an installation of PBXinAFlash. We have a current application that
> dials an outbound telephone number and plays a pre-recorded message. In the
> meantime, it also updates a mySQL database with the success or failure of
> the call. We call this ZAD and we have the source code (bash) to this
> application. The application monitors a mySQL table and when a new record
> appears, it gets the source and destination numbers from the table then
> makes the call with asterisk (using a call file). 
> We have another application called PAD. Our programmer told us that this
> application is what detects whether a human or answering machine has
> answered and determines when to start playing the pre-recorded message. It
> also reports back to ZAD (presumably) whether it was a human or answering
> machine that answered. We do NOT have the source code for this application
> and it won't be given to us.
> The issue is that PAD is incorrectly reporting human/answering machine
> constantly. This is causing issues for us. Unfortunately, we have not been
> able to get an update to the PAD application either. :(
> I've been looking for a replacement for PAD and found that asterisk 1.4
> comes with MachineDetect().  I'm just trying to figure out exactly how I
> could implement this.
> Or, if someone is aware of some open source solution for this (I can't
> imagine this is an unusual request).
> I'm new to asterisk programming, so please go easy on me. :)
> We just need a working solution that is at least 95% accurate. Right now we
> are looking at about 60-70% accuracy.
> Thanks!
> Dave
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Kind Regards,
   Nir Simionovich
   Asterisk Community Founder and Maintainer - Israel

   (e) nir.simionovich at gmail.com
   (w) http://www.simionovich.com

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