Echo on BCM50 comes and goes

[tjcbs]

I have a customer that has 9 lines on a bcm50 using the 1230 phones. Every couple of weeks 2 or 3 of the lines get internal echo on them then it goes away. I have gone through all the steps outlined in the echo control papers from Nortel and it works ok, then I get a call a couple weeks later and it will be on 2 different lines. It seems to only happen on phones that have the computer piggy backed through the internal switch. Could that be a problem? Also, I don't actually do anything other than come onsite and double check all the settings are still the same. I don't actually change anything on the bcm to make the echo stop.

 

[zktk01]

I know to correct loud sidetone I have adjusted impedance on the trunks before. I was only getting sidetone when accessing the Trunks not internal calls.