Selective Echo?

[dpaige10460]

I've been having an off and on issue with echo. It happens randomly to a few people calling similar areas out of NY state. Is it possible for echo to exist on specific numbers when dialing out?

 

[ADB100]

I have seen this a couple of times. It has to do with what trunk links are involved in the call - i.e. mixture of analaogue and digital trunks. There is usually adaptive echo cancellation techniques employed on the PSTN gateways to try to overcome the issues but the problem can still occur.

What gateways are you using?

Andy

 

[Wavesg]

What type of gateway and callmanager version are you running? Also is this a T1 cas or a PRI line? As ADB100 mentioned you can work with the echo cancellation.

Stay cool; it’s not over yet!

 

[dpaige10460]

We are running Call Manager 3.3(3)sr4a, two 3745 Gateways one with 2 PRIs and the other with 1.

 

[Wavesg]

Are the gateways MGCP or H.323???

Stay cool; it’s not over yet!

 

[dpaige10460]

Sorry MGCP

 

[Wavesg]

k..I would try adjusting the Echo TailLength and the Minimum ERL (db) first. If that doesn't work you might have to adjust the padding under "Audio Signal Adjustment into IP Network" and Audio Signal Adjustment from IP Network. If you can take a PRI and create a test calling search space. Place a phone under the same CSS and do the adjustments there. Of course do this at a off peak hours.



Stay cool; it’s not over yet!

 

[pndscm]

My best experience with echo cancellation is is to reduce the input gain on the PRI from 0 to -3. Then try to increase echo-cancellation a little at a time if still necessary.