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Call Echo - SIP Trunks & Digital Handsets 2

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JoeNewton

Technical User
Jan 14, 2012
56
GB
Hi guys,

I have a customer with an IP500v2 on R11. They have digital handsets (9504) and SIP Trunks, and for a while now they have been experiencing an echo on some calls. At first we thought it was the SIP at fault, the provider wanted examples, and the customer kept failing to provide enough in a short enough time to be of any use.

Eventually I went to site to try to get some examples myself. The calls worked fine to the majority of destinations, but had the echo when calling another of their sites with exactly the same set up (no SCN). The SIP provider listened back to the call and said they didn't hear an echo.

So I went back to site, sent a colleague to their other site, and made continuous calls back and forth with no issue. My colleague was using an analogue phone in one of their meeting rooms, so I asked him to borrow a digital phone instead, and straight away we got the fault, and on every call.

So it seems that the problem is with calls going from digital to SIP and then back to digital. So the question is why? Is it a faulty digital card, or a faulty VCM? Or is the SIP at fault some how? And which end is the problem likely to be, the one that can hear the echo or the one that can't?

Any help on this would be appreciated, its driving me mad!

Thanks,

Joe

Joe Newton
Avaya ACIS (SME), Avaya ACSS (SME), Mitel MCA, CompTIA A+, Cisco CCNA
 
Try these things:

1) I'm not sure if this setting is available on your handset. Try and see if it is there:
Press Home
Select Options & Settings
Press Select or OK
Select Advanced Options
Press Select or OK
Select Automatic Gain Control
Press Select or OK
To change the AGC status setting, scroll through the options for handset, headset, or speaker and press Change or OK
Press Save

2) In the System> VCM tab, change the nonlinear Processor mode from 'Adapative' to 'Silence'.

3) In the System> VCM tab, modify the 'Echo Return Loss' parameter.

This control allows adjustment of expected echo loss that should be used for the echo cancellation process.
Echoes are typically generated by impedance mismatches when a signal is converted from one circuit type to another, most notably from analog to IP.
To resolve this issue, an estimated echo signal can be created from one output and then subtracted from the input to hopefully remove any echo of the output.
The options are:
• 0dB
• 3dB
• 6dB
• 9dB


Depending on the URI configuration the ICR can be completely ignored.

If your URI is configured to use internal data then the IP Office will look into the user's SIP tab and if you have *'s it will look into ICR.

A madman with a taste for speed.
 
Hi there, thank you for your reply.

Sorry, I should have said, I have already tried suggestions 2 and 3. I will try the phone settings today.

Changing the Nonlinear Processor mode from 'Adapative' to 'Silence' works some of the time. Presumably what is happening is when no background noise is being picked up the audio stream is being stopped, which also stops the echo, but when background noise is picked up the echo is still there. Also the change from background noise to silence and back again is very off putting, possibly worse than silence.

With the 'Echo Return Loss' setting, the default is 6, so I tried both 9 and 0, but neither seemed to make a difference. Any idea which way should reduce echo? The help file is next to useless, it just lists the availabile options.

Thanks

Joe Newton
 
Avaya used to have a great article about how to stop echo on the IP Office. I used it many times by clicking this shortcut:


However, Avaya has taken that article down. If someone has a copy, I would sure love to have a hard copy of it. Should have just downloaded it myself...
 
I have a hard copy. Wish I would have saved the original as a PDF. The link below is a PDF copy of my hard copy. It isn't the best copy but it is readable.


Dermis and feline can be divorced by manifold methods.*
*(Disclaimer for all advise given)--'Version Dependent'
 
Thanks all. I'll have a read through the docs. However I think we have resolved it, it looks like it was a faulty combo card. I replaced it with a VCM32 and a DS8 and so far so good!

Joe Newton
 
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