[Asterisk-Users] Weird Echo Problem

[Brian M. Arlinghaus]

> Ok I know I'm not the only one having echo problem with asterisk but the 
> weird thing is that when I receive a call from a PSTN line on my TDM04B 
> card I don't have any echo problem at the beginning of the call then after 
> a few minutes I start having echo on my side only

> (the person calling from a regular phone doesn't have any echo),

I think that's the way it usually works... (i.e., only you hear the echo).


> then it stops and comes back all the way until the call is finished. It 
> does the same thing on outgoing calls from my Cisco 7960 phone to the PSTN 
> line.

The echo happens when you make a call from IP to a 2-wire PSTN Phone.


> I have no problem when it's an internal call from one 7960 to another one.

And you shouldn't.


> I tried a lot of different config in zapata.conf and the one that seems to 
> work the best for now is this one :
>
> context=incoming
> signalling=fxs_ks
> echotraining=800
> echocancel=yes
> echocancelwhenbridged=yes
> rxgain=0
> txgain=0
> immediate=no
> busydetect=no
> callprogress-no
> musiconhold=default
> usecallerid=yes
> callerid=asreceived
> group=1
> channel => 1-8
>
> Any suggestion why it starts doing echo after 5 minutes or so?

Martin,

I had a similar problem, but the echo would just come and go.  What are you 
using for your FXO ports?  Do you have the echo cancel turned on when you 
create those channels?  I'm assuming you do since your FXS ports start at 
one, and unless you specifically turned it off for your FXO ports, the echo 
cancel setting (and all other settings) will carry over from the previous 
channel settings.

I have a T100P/PRI for my PSTN connection, and I changed the T100P card to 
another pci slot on the same motherboard.  After that, the echo problem 
disappeared.  I just used echocancel=yes and echotraining=yes.  The default 
for echocancel is 128.  You can change that number too.

I never thought moving the cards around on the motherboard would matter, but 
after reading a few other posts and seeing that this fixed some other 
problems for people, I thought I would try it for my echo problem.  In fact, 
my echo problem started after a support guy at Digium had me move some cards 
around.  I erroneously attributed my new echo to the latest version of 
Asterisk that he installed and not to the moving of the pci cards.

I have also heard that changing motherboards will change things too.  But 
that might introduce different issues....

Regards,
Brian