Analog trunk echo after upgrading to 11.0, ATM Combo Card V2

[bishoptf]

I know, I know we are in the process of migrating to SIP trunk but I needed to upgrade in order to be able to purchase the SIP trunk licenses. We upgraded from 8.0 to 11.o and that seemed to go well, no major issues but I have users now complaining about echo where they were fine before. We have ATM combo cards and they were not supported in 11.1 so we went ahead and replaced them with the newer v2 versions, so maybe that changed something. I know the answer is to migrate to SIP trunks which is in work but will take some time, in the mean time anyone have any additional suggestions. I have tried turning off echo cancellation and echo reduction on the lines and that didnt seem to make much of a change and last night I turned on echo cancellation but left echo reduction off. I have read that maybe turning of AGC may help but looking for other suggestions, thanks.

 

[Nortel4Ever]

Is the cabinet properly grounded using the ground lug on the back connected to a known good ground?

Have you performed a manual impedence match on each individual trunk port, and not copying the suggested setting to the other 3 trunk ports?

 

[bishoptf]

Is the cabinet properly grounded using the ground lug on the back connected to a known good ground?

Have you performed a manual impedence match on each individual trunk port, and not copying the suggested setting to the other 3 trunk ports?

The cabinet that its in is properly grounded, I am pretty anal about that stuff but I do not have a connection from the grounding lug to the cabinet, I can do that but im sure if I metered it out I would see that it is grounded properly since its connected to the cabinet rails to the chassis but I can do it. I did not run a manual impedance match on each trunk, currently its set to automatic and they have all the same values, I wish I had looked at what was set before the upgrade. Again I replaced the combo cards with newer units, I have the older cards still and could roll them back but they are not supported in 11.1 so I replaced them to make when we upgrade to 11.1 once less thing to do.

 

[Nortel4Ever]

A few years ago I attended an IP Office Top Gun school put on by Tier 3 support personnel from Avaya. One of the sessions talked about the most common problems they see in their support role. The two suggestions I gave you were at the top of their list when vendors were complaining about echo on analog trunks. Even though there is auto impedence match it was strongly recommended to perform a manual match on each port.
Same too for the ground lug.

 

[bishoptf]

A few years ago I attended an IP Office Top Gun school put on by Tier 3 support personnel from Avaya. One of the sessions talked about the most common problems they see in their support role. The two suggestions I gave you were at the top of their list when vendors were complaining about echo on analog trunks. Even though there is auto impedence match it was strongly recommended to perform a manual match on each port.
Same too for the ground lug.

Understand and appreciate the input, I will be on site this weekend and make sure the ground is good and run the impedance tool manually on each line

 

[jose1000]

You can also disable the auto impedance. Just put the old 600 ohms impedance and the echo is off. At least that worked for me.

 

[bishoptf]

You can also disable the auto impedance. Just put the old 600 ohms impedance and the echo is off. At least that worked for me.

There are 2 echo settings echo cancellation and echo reduction, did you turn both of those off?

Thanks

 

[jose1000]

No, I didnt turn them off. In the same form, just above Echo Cancellation and Echo Reduction, says "Impedance Match". There set off the "Automatic" and you can select the Impedance. You may try with Default or with 600 Ohms. That worked for me.