[Asterisk-Users] Reducing echo on FXS port

[Giovanni Miano]

Try

In chan_zap.c change the following line:

#define READ_SIZE 160

to

#define READ_SIZE 16

In zapata.conf

jitterbuffers=40

This will also increase system load by a factor of 10.

2006/1/15, Aryanto Rachmad <aryanto.rachmad at chello.at>:
>
> Hello everybody,
>
> I am sorry to bring this up again if this kind of echo issue has ever
> discussed.
>
> Phone2 in below call path experiences quite annoying echo:
>
> Phone1 --> FXS (TDM400P) --> Asterisk --> SIP GW --> PSTN --> Phone2
>
> It is annoying as on phone2, we can hear the whole words we say with the
> level of maybe 25% of the original sound. I can reduce the echo to maximum
> with the following settings for my FXS port on zapata.conf:
>
> rxgain=-8.0
> txgain=2.0
> echocancel=256
> echotraining=500
>
> But it is still not entirely eliminated as we still sometimes hear the
> last syllables, with the level of maybe 5% of the original sound.
>
> What I did was just playing around with the values of those parameters,
> use ztmonitor to have the FXS rx/tx signal visualised and use only my ears
> to check it. I think my ears are fine :), as I do this because my friends
> complain about the echo they hear.
>
> Does anybody know a better method to find the best value for those
> parameters?
>
> There is no echo on phone2 when I use softphone like this:
>
>  PC(X-Lite) --> Asterisk --> SIP GW --> PSTN --> Phone2
>
> The following is the version of asterisk I am using:
>
> CLI> show version
> Asterisk SVN-branch-1.2-r7999 built by root @ atvie-asterisk on a i686
> running Linux on 2006-01-13 06:15:02 UTC
>
> And I set the echo canceller in zconfig.h to ECHO_CAN_MG2.
>
> Cheers,
>
> Anto
>
>
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>


--
Giovanni Miano
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