I have a strange echo problem. When speaking on the phone with someone, I hear MY OWN voice with a sever echo. The other party sounds perfect, and they can hear me perfectly. It is as if only the sidetone has an echo. I'm running * on a dedicated box, small LAN, and am using 4 FXO cards to connect the box to PTSN lines. My phones are Polycom IP500 SIP phones. The only echo cancellation stuff that I can find relates to cancelling echo between my system and the PTSN lines. Since the call is "perfect", I don't see how this would apply. Any suggestions?? -N
> I have a strange echo problem. > > When speaking on the phone with someone, I hear MY OWN voice with a > sever echo. The other party sounds perfect, and they can hear me > perfectly. It is as if only the sidetone has an echo. > > I'm running * on a dedicated box, small LAN, and am using 4 FXO cards to > connect the box to PTSN lines. My phones are Polycom IP500 SIP phones. > > The only echo cancellation stuff that I can find relates to cancelling > echo between my system and the PTSN lines. Since the call is "perfect", > I don't see how this would apply. > > Any suggestions??Try these parameters for each zap channel: echotraining=800 echocancel=yes echocancelwhenbridged=yes Don't forget you have to stop and restart asterisk. a reload will not work.
On Tue, Apr 12, 2005 at 10:16:16AM -0700, Noah Silverman wrote:> I have a strange echo problem. > > When speaking on the phone with someone, I hear MY OWN voice with a > sever echo. The other party sounds perfect, and they can hear me > perfectly. It is as if only the sidetone has an echo. > > I'm running * on a dedicated box, small LAN, and am using 4 FXO cards to > connect the box to PTSN lines. My phones are Polycom IP500 SIP phones. > > The only echo cancellation stuff that I can find relates to cancelling > echo between my system and the PTSN lines. Since the call is "perfect", > I don't see how this would apply. > > Any suggestions??If you're using a TDM card, you might see if the fxotune program will help. It does impedance tuning of the card and finds the line impedance that has the lowest mean power (i.e. least echo). I've been working on it for a while and some people have had some success with it. Matthew Fredrickson
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 _______________________________________________ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Noah Silverman wrote:>I have a strange echo problem. > >When speaking on the phone with someone, I hear MY OWN voice with a >sever echo. The other party sounds perfect, and they can hear me >perfectly. It is as if only the sidetone has an echo. > >I'm running * on a dedicated box, small LAN, and am using 4 FXO cards to > connect the box to PTSN lines. My phones are Polycom IP500 SIP phones. > >The only echo cancellation stuff that I can find relates to cancelling >echo between my system and the PTSN lines. Since the call is "perfect", >I don't see how this would apply. > >Any suggestions?? > >-N >_______________________________________________ >Asterisk-Users mailing list >Asterisk-Users@lists.digium.com >http://lists.digium.com/mailman/listinfo/asterisk-users >To UNSUBSCRIBE or update options visit: > http://lists.digium.com/mailman/listinfo/asterisk-users > >We have a similar problem. We are using Polycom IP600 phones with a PRI line. Randomly there will be the sidetone for an agent answering the queue on the call. I have used ZapScan and do not hear the echo either. It is just the agent's voice echoed back. I have so far been unable to reproduce the echo from external lines I test with. The other end never hears it. Since the problem does not happen to all calls, I not altered the rxgain/txgain in zaptel.conf yet. It almost seems like there is some qwirk with Polycom's DSP and asterisk that is causing it. The users haven't been reporting it as much now either. So either they got sick of telling me and not having it fixed or whatever caused it is gone. --johann