[asterisk-ss7] asterisk oh323 - chan-ss7 echo problem

[Anton]

Dear Jacob,

Any chance to give us any timing approximation for a next 
version?

Regards,
Anton.

On 28 April 2006 17:26, Jacob Tinning wrote:
> On Tue, 18 Apr 2006, leonimar cape wrote:
> > Can someone give a suggestion on what I should do to
> > omit the echo. Here is may scenario
> >
> >      ---  h323   ---   chan-ss7    ---
> >  A---|  |--------|  |--------------|  |----B
> >      ---         ---               ---
> >     Nextone    Asterisk         DMS
>
> The next version of chan_ss7 will include
> enabling/disabling of the zaptel echo-canceller, which
> probably will solve your problem.
>
> > The calling party can hear every words he/she say
> > after 1  to 2 seconds. But the called party can hear A
> > with no echo and the quality is clear. I have already
> > tried it in both digium (TE410P) and  sangoma card
> > (AT104) and the results where the same. Is there any
> > way that I can cancel the echo? Any particular
> > settings that I have to change in the settings of the
> > asterisk?
>
> The current version of chan_ss7 does not do anything to
> avoid echo. It just passes the audio through the
> channels.
>
> The problem is when A calls an old analog phone B. Old
> analog phones typically bleed some of the audio back to
> the sender.
>
> Ordinary synchronous telephone-networks doesn't delay the
> audio very much ( < 10ms) so the caller will not notice
> any echo.
>
> Unfortunately, ip-networks induce more delay ( > 70 ms )
> which will clearly sound as echo.
>
> To avoid the echo, the only (as far as I know) solution
> is to insert some kind of echo-canceller "in" or "to the
> right" of Asterisk in your drawing.
>
> As noted above, the next version of chan_ss7 will start
> the zaptel echo-cancellation when a new call is made
> (this is configurable, if you don't want
> echo-cancellation), and stop it again when the call is
> finished.
>
> Mvh. Jacob