Random Echo issues between remote site and other voip sites?

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Sep 15th, 2010
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We just recently added a new remote site to a cluster and there are complaints about an echo on calls between sites.   The echo happens very intermittently.  The current setting on the PRI's echo cancellation is 64.  Where other than the gateway PRI's can I check the Echo settings that may be causing the issue?

Any feedback or suggestions would be great.

Thank you.



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David Smith Wed, 09/15/2010 - 13:55
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Any echo you recieve is coming off the PSTN tail circuit.

So if you make a call from the host site, to a new remote site via IP...then out PRI, then echo is coming back in on the PRI.  Echo isn't generated off IP-IP.

All the echo cancellation that you have is going to be set at the terminating GW/DSP.

From 12.4(20)T onwards you can increase your echo cancellation to 128 ms coverage, the older IOS only went up to 64.  This is to compensate for delay on the PSTN tail circuit.  You can try that.

You can also set the below on your terminating voice-port to compensate for an ERL that is too low:

conf t

voice-port X/X

input gain -3

output attenuation 5

Echo troubleshooting guide:


Other than that, if ERL is correct and there's not too much delay, there may be something going on with the DSP you can't control.



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