[asterisk-biz] Custom AMD Module for Improved Answering Machine Detection Needed

[Alex Balashov]

Yep.  That confirms my general impression, which is that 70% is about 
the highest rate of accuracy you're ever going to get, and it is 
possible to come reasonably close to that with Asterisk's built-in AMD.

The essence of the matter is that in general, over that 60-70% point 
come diminishing returns.  Not even 80/20 diminishing returns - more 
like 95/5.

Al Lougher wrote:

> I'll give you my two cents, if only to give you a good idea of what you 
> can expect to uncover in your search for the holy grail of answer 
> machine detection systems. And as one of your competitors in this space 
> I cannot give away too many trade secrets :)
> 
> Alex is right on the money, there is no best, or single, answer machine 
> detection process for asterisk based systems. AMD will only get you so 
> far. In fact, you'll find you'll need a combination of custom processes, 
> each one increasing the detection rate by a small %. There is a white 
> paper somewhere outlining issues with answer machine detection (if I 
> find it I'll send the URL) and even the research done in that paper 
> which tested some of the more advanced industry detection applications 
> gave an overall 70% accuracy in detecting machines.
> 
> I can tell you that we employ a combination of customer AMD modules, 
> carrier detection, wireless detection, SOX silence stripping, 
> BackgroundDetect, DTMF and more just for our machine detection process. 
> It also took us two years to perfect it and yet every week we get the 
> "my message isn't being left on my voicemail" support issues.
> 
> So as you can see the answer is not a single process but a combination 
> of processes that improves your overall detection rate.
> 
> Hope this helps.
> 
> Alan
> www.group2call.com
> 
> --- On *Tue, 10/7/08, Alex Balashov /<abalashov at evaristesys.com>/* wrote:
> 
>     From: Alex Balashov <abalashov at evaristesys.com>
>     Subject: Re: [asterisk-biz] Custom AMD Module for Improved Answering
>     Machine Detection Needed
>     To: "Commercial and Business-Oriented Asterisk Discussion"
>     <asterisk-biz at lists.digium.com>
>     Date: Tuesday, October 7, 2008, 9:56 PM
> 
>     The best off-the-shelf solution I've seen for this comes from Paraxip in 
>     the form of their NetBorder CPA (Call Progress Analysis) product.  They 
>     use a B2BUA that you can send calls through out of Asterisk, and which 
>     will return a certain code as a custom SIP header depending on the 
>     disposition.
> 
>     "The best" still isn't saying much.  You're going to get many
>     of the 
>     same problems as you get with AMD.  The marginal improved accuracy may 
>     or may not be worth the cost.
> 
>     That's just how it is.  This is impossible to do right in a way that is 
>     applicable to the variance of environmental and acoustic situations - as 
>     you mention, works with one carrier and not with another, and other 
>     variables.  Most likely, developing such a thing would be a pointless 
>     waste of time and energy because to get beyond a certain rate of 
>     accuracy is to ask for a perpetual motion machine.
> 
>     Just my $.02,
>      of course.
> 
>     Chris wrote:
> 
>     > We're looking for a company (preferably U.S. based) that can help us 
>     > with the development of a custom module for advanced Answering Machine 
>     > Detection.  We need to be able to properly detect a live answer vs. an 
>     > answering machine or voicemail (including cell phone ringbacks, etc.) as 
>     > well as wait for the beep to leave a message.  We've tried tweaking
>     the 
>     > built-in AMD settings for Asterisk, but all this accomplishes is 
>     > improving detection rate for one carrier and eliminating it for 
>     > another.  We're looking for a company that has worked on similar 
>     > projects before that could help us with a potential solution.  Thanks in 
>     > advance!
>     > 
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> 
>     -- 
>     Alex Balashov
>     Evariste Systems
>     Web    : http://www.evaristesys.com/
>     Tel    : (+1) (678) 954-0670
>     Direct : (+1) (678) 954-0671
>     Mobile : (+1) (706) 338-8599
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-- 
Alex Balashov
Evariste Systems
Web    : http://www.evaristesys.com/
Tel    : (+1) (678) 954-0670
Direct : (+1) (678) 954-0671
Mobile : (+1) (706) 338-8599