atcomsystems.ca/forum Forums TDM Business Telephone Systems Nortel Telephones & Systems BCM 450 REl 6 noise on PRI

I have a site that has 2 PRI circuits. They are having an issue with "noise", some crackling and popping. Ive tested this and it appears to be on the incomoing DID calls. They have 2 banks of DID's, different area codes but boh local. They added the second T1 a few months ago. I have both T1's in the same pool so the second T1 handles the outbound calling and the first T1 handles the inbounds. Im only noticing the noise on the original DID bank the customer has. When i pull the first T1, all calls come in through the second T1 but i still get the noise. I have swapped the T1's around in the switch, and swapped the T1 cards. The carrier sees no errors on the circuit. Im getting a little stumped as the where this noise is coming from. My thought is that its in the network but unsure how or where to have the carrier look. Any help is appreciated.

Check the CSU stats for Bi polar violations. Sounds like the PRI is slipping. This will cause crackling, and popping on the lines. If it's bad enough, cut offs. It's more then likely a clocking issue. Check to make sure your clocking off the span, and not in free run.

Have you checked for Patches? There are known issues around this and patches out there to correct it to, as well as it is most likely a PRI and Clocking issue-