[Asterisk-Dev] IAX to zaptel echo

[Steven Critchfield]

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Suggestions to your problem below.

On Wed, 2003-08-20 at 13:16, Claude Klimos wrote:
> Hi all,
>  
> I am experiencing a problem with the quality of the voice
> communication between an IAX based softphone (WinIAX) and an outside
> line through a FXO port or even with a regular analog phone connected
> to a FXS port. The party using the IAX softphone hears his own echo a
> plit of a second after speaking. The party on the analog end does not
> experience any echo. I tried to modify the KFLAG parameter in the
> Makefile of zaptel to change the algorithm without results. I also
> tried to modify the value of the echocancel paramter in zapata.conf
> (tried 32,64,yes/128,256) without success. Note the parameter
> echocancelwhenbridged is set to yes.
>  
> On the other hand, when I establish a communication between two IAX
> softphones, I hear no echo. This leads me to suspect the cards I am
> using. I have one X100P and one TDM400P card with 2 modules enabled.
>  
> I would like to know if anyone encoutered this problem and how to
> minimize/eliminate the echo, if possible. Also, we will eventually be
> using a PRI with a T100P or a T400P, would the echo problem still be
> present?

My office experienced echo over IAX on a low latency link. We solved
this by turning off the jitter buffer. I can tell you that it isn't a
problem with your cards. I have a T100P at home with no problems
connecting to my office pbx via IAX. I have a T100P in my office
connected via IAX to my colo machine.  My Colo machine has a T400P
connected to the outside PSTN. I only needed to adjust the jitter buffer
on my office system because latency was so short making a single hop
over a private data T1. 

 
 

-- 
Steven Critchfield <critch at basesys.com>