A Time and Materials customer of mine just upgraded their local T1 to a PRI and ever since the far end hears a clicking noise every 13 seconds. It doesn't matter if the call originates from here or the call comes in from the outside. The network event log shows event 327-00 happened 255 times yesterday and the same today. I believe this is running on 6.1 system version is 30CQE06 NAT. MCI says they see errored seconds on the span ,but last night ran all their test patterns with no errors of course.