[Asterisk-Users] Re: Incoming echo cancel

[Eric Wieling]

Nenad Radosavljevic wrote:

> Same problem here: if call come over ISDN PRI and it is for a SIP phone 
> that equals to strong echo situation, at the SIP end. Interestingly this 
> doesn't happen on all calls but it does on 95% of them. Asterisk load at 
> that moment is insignificant - 1 to 2 calls.
> 
> I have tried with all possible echo cancellers in zconfig.h, with and 
> without MMX, and with and without CFLAGS+=-march=i686 in zaptel 
> Makefile, but without any success.
> 
> TE110P is on its own interrupt - no other cards on board except Intel 
> chipset PCI LAN card (on shared interrupt) and machine is Intel 685 
> chipset based, with P4 Celleron 2.6 GHz, 1Gbyte RAM, WD 10K RPM IDE HDD.
> 
> I have even contacted Digium support with this issue, but except a 
> request for some additional explanations of my setup, nothing from them 
> so far (for about a week).
> 
> Anyone have an idea, why this type of echo happens ? As far as I have 
> read on the lists this type of echo should not occur at all, but it 
> simply does !

I consider all this MMX stuff to be voodoo for echo problems.

If you have a PRI and SIP phones then the echo occurs on the far end 
analog phone.

/etc/asterisk/zapata.conf:

echocancel=yes
echotraining=yes or 600 or 800

Yo have to STOP and restart Asterisk for changes in 
/etc/asterisk/zapata.conf to take effect.  You can unload chan_zap.so 
and reload it as well, but wby bother.

--Eric