[Freeswitch-users] FAS detection with FS

[Ahmed Naji]

Hi Valsis,

Thanks for this.

My line of thought is to tone-detect secondary ringing tones post 200(OK) to
detect FAS (False Answer Supervision). This should eliminate at least a good
proportion of calls, and it can be done real time through a
script/modules/...etc.

Working along this thought, at least you are minimising the hit cost-wise to
a few seconds at most.

As to answering machines and fake conferences, fake network messages ...etc,
one can possibly use voice detection, perhaps with heuristic and statistical
training.

Just a thought ..

Regards,

Ahmed.


2010/1/8 Vlasis Hatzistavrou (KTI) <vhatz at kinetix.gr>

>  Hello Ahmed,
>
> I don't think there is a reliable way to detect FAS on a per call basis.
> Even audio detection software can be confused by strange ringtones,
> answering machines, etc.
>
> The most reliable way we have found is to use statistics from CDRs and see
> if the INVITE-to-200(OK) delay averaged over a number of calls appears to be
> too small. If it is, then it is possible that you got FAS for those calls.
>
> But this can only tell you if you have been experiencing FAS in past calls,
> ie you will not know you are getting FAS in real time.
>
> It is still useful however: after you detect a possible FAS case via
> statistics you can place a few test calls yourself to verify that there
> actually exists FAS (and this is the only information that a carrier will
> accept in a trouble ticket to prove to them that they actually give you
> FAS).
>
> I hope this helps.
>
> Best regards,
> Vlasis Hatzistavrou.
>
>
> On 8/1/10 3:05 πμ, Ahmed Naji wrote:
>
> Hi everyone,
>
> Was just wondering what/if anyone is doing any work on FAS detection and
> spoofed ring tones. Be great to discuss some ideas.
>
> Regards,
>
> Ahmed.
>
> --
> Ahmed Naji
>
>
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-- 
Ahmed Naji
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