I have a working XTS MPB2 Ver 4.0 PRI using a CSU. AT&T had the customer upgrade to a BVoIP PRI with a Router on site. When I bypass the CSU and plug into the router the PRI won't come up, Yellow alarm. I made a crossover cable, tried a straight cable, and 2 Pri cards one with DB15 and RJ45. AT&T says its a connection problem. Ideas?