Have the same problem with both release 1 and 2 BCM50 at multiple sites. We have 2 telco providers where I am located and this problem is only apparent with 1 of the providers, and never the other. Also, Line issue only affects lines 3 and up, never 1 and 2.
Have tried system swaps, nortel provided (padded)RJ21 cable, calls to the telco provider (line is noise free at demarc) with no success.
We traced problem in release 1 to the Service Update 2 patch from nortel. BCM is fine before patch, and after patch line noise occurs. Level 2 reset to defaults, noise gone.
With release 2 we have found no solution as of yet and are working with Nortel for resolution.
I'd really like to hear from anyone who has come across this issue since it would be "Very" helpful to me.
Thx all