I just added a second PRI card to a customers IP Office. The PRI is turned up and ready to go, however, when we try to test, it's not working. We try to unplug the main PRI to see if we get dial tone from the second, and it's saying not in service. If we flop the two PRI's, the one in the first card works fine. Is there something in particular that needs to be configured to get both PRI's to work?