[asterisk-users] What are the reasons for VoIP echo?

Thu Oct 1 20:42:50 CDT 2009

Indeed there are! - John

On Thu, 2009-10-01 at 20:18 -0500, Martin wrote:
> Are you saying there are half duplex phones out there ???? with half
> duplex speakerphones ?
> 
> All analog phones are full duplex ...
> 
> Anyways the echo can be created by the analog phone even when it's
> connected to the
> sip ata or even the sip phone ... then you usually have acoustic echo
> which goes from speaker
> to microphone of the handset ... that should be cancelled by the sip
> phone/device... or someone out there will
> hear echo
> 
> Martin
> 
> On Thu, Oct 1, 2009 at 7:57 PM, John A. Sullivan III
> <jsullivan at opensourcedevel.com> wrote:
> > I'm quite new to all this but I was under the impression that most
> > electrically induced echo was at the physical interface to the PSTN.  If
> > one is using SIP trunking, I would think this would point to a carrier
> > issue.
> >
> > We also hit an interesting problem with echo today but I don't think
> > this is the issue Myles is having.  We installed fairly high end phones
> > with full duplex speakerphones.  Callers are having a bad problem with
> > echo when the users use the speakerphone.  Because it is full duplex
> > rather than half, if the speakerphone volume and speakerphone mike
> > volume are turned up, the callers are indeed hearing themselves by
> > virtue of the higher quality full duplex!
> >
> > On Thu, 2009-10-01 at 19:36 -0500, Martin wrote:
> >> if a user calling you hears echo of himself then it's the fault of
> >> your sip device/sip phone.
> >> The manufacturer must be using a cheap or an open source echo canceller ...
> >>
> >> try getting a different sip device made by some 'normal' company like
> >> polycom or linksys/cisco
> >>
> >> Martin
> >>
> >> On Thu, Oct 1, 2009 at 9:10 AM, Myles Wakeham <myles at techsol.org> wrote:
> >> > I have an Asterisk 1.4.2 system that has been installed for about 3
> >> > months now in our home.  We converted all of our phones to SIP phones,
> >> > and use two different trunk providers (BroadVoice for incoming &
> >> > FlowRoute for outgoing).
> >> >
> >> > Most of the time its working flawlessly.  But about 1/3rd of the calls
> >> > that come into us complain of an echo and what is best described as
> >> > latency issues.  Its not consistent though.  I was on the phone with an
> >> > insurance company yesterday for about 1 hour and the call was perfect (I
> >> > originated the call which used Flowroute for the SIP provider).
> >> >
> >> > What seems to be a pattern here is cell phones.  When we receive a call
> >> > from a cell phone, or from certain people on certain phone systems, they
> >> > consistently complain of echo in the call.  Its far less regular when we
> >> > originate the call, which suggested to me that the problem might be with
> >> > Broadvoice.  But I'm now hearing that us calling back the party doesn't
> >> > always solve the problem either.
> >> >
> >> > We upgraded our Internet feed (we're on a cable Internet through our
> >> > cable company, with 12mb/s down, 1.5mb/s up) and that seems to have
> >> > helped but not solved this problem.  From what I can see, its some form
> >> > of latency issue.  We use IPCop as a firewall for our Internet access,
> >> > but have turned off any IDS on it so that its running fast.  I can play
> >> > online computer games through the network with no issues at all, so I
> >> > don't think its slowing down the traffic and if it was I'd expect this
> >> > problem to be occurring consistently on all calls.
> >> >
> >> > Are there any tweaks that I can do with Asterisk to increase the network
> >> > performance to reduce these issues?  Have others who have experienced
> >> > this been able to identify the issues to external VoIP SIP providers
> >> > only, or does our system have something to do with all of this?  At the
> >> > time of the calls coming in, IPCop is telling me that we don't have more
> >> > than 100K/s of bandwidth in use, and according to the network bandwidth
> >> > graphs there, even with 2 people on the phone at the same time, the
> >> > bandwidth never seems to exceed 300K/s, so I think we have plenty of
> >> > headroom for this.  I checked with our cable provider for issues with
> >> > modem latency, and they couldn't detect anything.  Again, I'm not
> >> > experiencing any lag issues with computer games, particularly those that
> >> > are heavy in interactivity, so I don't think that is the reason.
> >> >
> >> > Any suggestions as to what could be tweaked would be greatly appreciated.
> >> >
> >> > Myles
> >> > --
> >> > =======================
> >> > Myles Wakeham
> >> > Director of Engineering
> >> > Tech Solutions USA, Inc.
> >> > Scottsdale, Arizona  USA
> >> > http://www.techsolusa.com
> >> > Phone +1-480-451-7440
> >> >
> >> >
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> > --
> > John A. Sullivan III
> > Open Source Development Corporation
> > +1 207-985-7880
> > jsullivan at opensourcedevel.com
> >
> > http://www.spiritualoutreach.com
> > Making Christianity intelligible to secular society
> >
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-- 
John A. Sullivan III
Open Source Development Corporation
+1 207-985-7880
jsullivan at opensourcedevel.com

http://www.spiritualoutreach.com
Making Christianity intelligible to secular society