asterisk users - Apr 2006 - Problems with several SIP Providers (one way echo)

Hi! 

First I want to say hello to the complete list. I am new and I have a
problem, where I did not find an answer in the archives and on 
voip-info.org ...

I am subscribed to two SIP Providers:
1. SIPCall.at
2. SIPGate.at

SIPCall works fine with signalling (incoming and outgoing calls), but
the connections terminates without any feasible error. In addition there
is also a minor echo on the line.

SIPGate works also fine (better than SIPCall) but the ECHO is terrible.
My side (* server) connected with X-Lite Softphone has a great quality,
but the PSTN caller hears his voice with an echo.

Did anybody already had such a problem? Do you think that my * server
config (sip.conf) is the problem (but internally everything works
great!) or is that a Provider issue?

Thanks for your help,
Alex

Alex Mosburger schrieb:
> ...
> SIPGate works also fine (better than SIPCall) but the ECHO is terrible.
> My side (* server) connected with X-Lite Softphone has a great quality,
> but the PSTN caller hears his voice with an echo.
> 
> Did anybody already had such a problem? Do you think that my * server

Hi,

I assume some accoustic feedback (speaker -> microphone) in
your headset or what else you are using, or feedback
inside your soundcard. (Some sound cards are able to feedback
PCM-in to PCM-out. In this case, check, that rec-volume for that channel
is 0!)

In both cases, the gateway to PSTN (operated by your SIP provider
or its partner) should reduce the echo notably, because they
typically run bidirectional echo cancellers.

Thus, look for a provider which combines good echo cancellation
_and_ reliable signalling! Maybe the very cheapest provider is not
the best one.


Roger.

...
I forgot in my previous email one further issue:

Maybe the ping round trip to your SIP provider and thus
to the PSTN gateway is too long. The echo cancellation
is typically limited to a reasonable echo run time.

If the time is too long, echo cancellation will fail,
because it would be too much, in most cases unnecessary, effort.


Most DSL providers do offer "fast path" or similar things with
improved ping times (e.g. below 30 ms instead of 70 ms).


Roger.

Thanks fort he fast feedback Roger!

It is not my end hearing or producing echo. My voice is heard correctly
without any echo, but the other side hears his OWN voice several msec
later... MMhhhh... a switch to another provider is in this case a good
idea... ;)

Alex

-----Original Message-----
From: asterisk-users-bounces@lists.digium.com
[mailto:asterisk-users-bounces@lists.digium.com] On Behalf Of Roger
Schreiter
Sent: Sonntag, 16. April 2006 18:35
To: Asterisk Users Mailing List - Non-Commercial Discussion
Subject: Re: [Asterisk-Users] Problems with several SIP Providers (one
wayecho)

Alex Mosburger schrieb:
> ...
> SIPGate works also fine (better than SIPCall) but the ECHO is
terrible.
> My side (* server) connected with X-Lite Softphone has a great
quality,
> but the PSTN caller hears his voice with an echo.
> 
> Did anybody already had such a problem? Do you think that my * server

Hi,

I assume some accoustic feedback (speaker -> microphone) in
your headset or what else you are using, or feedback
inside your soundcard. (Some sound cards are able to feedback
PCM-in to PCM-out. In this case, check, that rec-volume for that channel
is 0!)

In both cases, the gateway to PSTN (operated by your SIP provider
or its partner) should reduce the echo notably, because they
typically run bidirectional echo cancellers.

Thus, look for a provider which combines good echo cancellation
_and_ reliable signalling! Maybe the very cheapest provider is not
the best one.


Roger.

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