[Asterisk-Users] Local Echo

Neal Walton
Wed, 13 Apr 2005 07:36:02 -0000

Hi,
It's not probable that the delay is "just in the sidetone".  It is
more
probable that the echo is caused by reflected energy somewhere very far
downline, perhaps even at the far terminating end of the call.  Yes, I know
that the person at the far end of the call does not hear an echo, but that
doesn't mean that the far end is not the cause of the problem.  Think about
this:  If I scream and the energy is reflected by the wall of a building, I
will hear an echo.  If you stand at that wall and listen, you will only
hear me scream but not the echo.  You will never hear an echo at the point
where the reflection occurs because there will be no delay at that point.
 You will only hear an echo somewhere away from the reflection point so
that the signal will have some time delay caused by the travel path.  If
you hear an echo, the reflection is somewhere away from you so that there
can be a delay caused by the signal going somewhere and then coming back.
 Try this experiment: call a number that is answered directly by the
asterisk box and see if you get the echo.  If you do, it is definitely a
local problem.
Regards,
Neal


-----Original Message-----
From:	Adam Goryachev [SMTP:mailinglists@websitemanagers.com.au]
Sent:	Tuesday, April 12, 2005 9:15 PM
To:	Asterisk Users Mailing List - Non-Commercial Discussion
Subject:	Re: [Asterisk-Users] Local Echo

On Tue, 2005-04-12 at 17:13 -0700, Noah Silverman wrote:
> Thanks Jeff,
>
> Your explanation helps.
>
> You are correct.  There is delay in the sidetone.  It annoys me, but the
> other party doesn't her it.  (You're right that the other party is
on a
> POTS line.)
>
> I assume that the echo must be between the SIP phone and Asterisk.
> Since the actuall call sounds fine to both me and the other party, then
> the Zapata stuff must be working fine.  Right??

No, thats what everyone keeps telling you.
Everything is working fine on both ZAP and SIP sides, just that there is
some delay, and therefore you hear echo.

So start reading the advice that other people are offering.

One thing that other people haven't mentioned, is that if you are not in
the US, then you should also set the OPERMODE value to your country.

> Interesting, If I call someone who doesn't pick up right away, I can
> still hear myself echo really badly if I talk into the phone while it is
> still ringing at the other end.  Does this help??

Strange/interesting, but I personally don't know enough about this to
comment further.

Regards,
Adam

--
 --
Adam Goryachev
Website Managers
Ph:  +61 2 8304 0000                        adam@websitemanagers.com.au
Fax: +61 2 9345 4396                        www.websitemanagers.com.au
--
 --
Adam Goryachev
Website Managers
Ph:  +61 2 8304 0000                        adam@websitemanagers.com.au
Fax: +61 2 9345 4396                        www.websitemanagers.com.au

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