We have recently installed a new intrgrated T-1 circuit for our business. We have a Tadiran phone system(PBX) with auto attendant. Our new service provider has installed an Adtran 600 series(MGCP) IAD at our location and the new service provider uses a Metaswitch, don't know model #. Since the installation was completed we have a ton of phantom calls / ghosting/ ringback. We have pinpointed it to be a disconnect supervision problem - we think. We can duplicate the problem by calling in and when the auto attendant answers hanging up. When listening on a butt set the call is never released. Disconnect supervision is turned on at the Metaswitch and I think is set for 900 ms. Adtran has been no help. Any suggestions would be greatly appreciared
Metaswitch / Adtran disconnect supervision 
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