I have end users reporting cross talk on about 10 out of 100 calls daily and sporatically.Typically happens more during peak hours. We were getting cross talk on about 5 out of 10 calls, but we were able to do some testing with avaya and narrow it down to a medpro sitting in a bad slot on a carrier. Swapped the medpro used same slot still same issue, swapped entire carrier and used same boards and we dropped from 5 out of 10 calls daily to 1 out of 10 calls daily. Crosstalk improved greatly and now I am unable to reproduce it as easily, which is making it hard to pinpoint the remaining problem. I have been working with Avaya since Sept and replaced a pn that we thought was causing the lingering crosstalk on 1 out of 10 calls daily, but that did not work. The weird thing is that we have 2 call centers, 1 has an IVR and 1 doesnt, and the one that does not have an IVR can still hear the IVR crosstalk. The only thing that routes from the IVR building to the non IVR building is a trunk group as all trunk groups route into the buidling with the IVR and are ip connected to other buildings. The IVR building is our main buiding with about 14 port networks. The non IVR building has its own single port network. Anyone have any suggestions on what the next step would be. BTW this all started happening when our core switch went down and was brought back up. I am at a loss right now and unable to figure this thing out.