[Asterisk-Users] Echo cancellation

[Erick Baum]

Asterisk performs echo cancellation for all incoming and outgoing calls
through the T1/PRI card.  However, there are some things that can still
cause echo's.  We had a similar situation a with a setup much like yours.
We switched to the MG2 echo canceller which helped quite a bit.  But
finally, after testing everything else we possibly could, swapping out PRI
cards, changing every concevable setting related to echo, and having the
phone company out about a dozen times to check the PRI, we ended up
switching companies from Telepacific to Sprint and the echo problem,
according to the users, completely went away.

However, a couple things you may want to look at is the audio gain settings
in your zapata.conf and make sure they're not set too high, maybe even try
dropping them down a bit.  And try the MG2 echo canceller if you haven't
already, it seems to provide the best results on PRI's, at least as far as
our testing has gone.

Erick


On 1/3/06, Aaron Daniel <amdtech at shsu.edu> wrote:
>
> We currently have about 60 cisco 7940's, which were converted from cisco
> call manager to be used for asterisk.  We're running 1.2.1 stable on 4
> systems (primary server, backup server, gateway, and voicemail).  The
> phone lines come into the gateway on a digium te405p.  The problem we're
> having is that the 7940's are echoing on outgoing calls, and I'm not
> sure what else to try (I did just recompile zaptel with a different echo
> canceler to see if it would help), but I seem to remember asterisk
> doesn't do echo cancellation on outgoing calls.  I researched a bit on
> qos and latency, but there's maybe a 10ms latency between the phone and
> the outgoing line, so I ruled that out pretty quick.  Any help is
> greatly appreciated.
>
> Aaron
>
> On Tue, 2006-01-03 at 21:26 -0800, Erick Baum wrote:
> > Can you provide some details about the system, what version of
> > Asterisk, what kind of phones, what kind of phone lines, etc.
> >
> > Erick
> >
> >
> > On 1/3/06, Aaron Daniel < amdtech at shsu.edu> wrote:
> >         I've got a slight problem with echo.  Basically, most of the
> >         outgoing
> >         phone calls on our system echo, but as far as I can tell, the
> >         incoming
> >         echo has been relatively fixed, with just a bit of work left
> >         to do on
> >         it.  I read somewhere that asterisk doesn't echo cancel on
> >         outgoing
> >         calls, am I wrong in that assumption, and if I am, what else
> >         can be done
> >         when the echo training and echo cancel tapping isn't working?
> >
> >         Aaron
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