Thankfully we did not have to replace the box. And yes, trying to get a RMA through Nortel or a stocking distributor is a pain in the ass.
The problem turns out to be with the paging amplifier the BCM was connected to. The amplifier (Valcom 2001) has a MUZAK player attached to the Music input and the Paging input is attached to BCM. This scenario has been in place for almost a month and the paging stops working all of a sudden. We had to remove the MUZAK input from the Valcom to allow paging to work. In order to reconnect the MUZAK we had to reverse the polarity going into the Valcom. Without knowing if something was physically changed on the MUZAK end, it is a mystery as to why the polarity reversal solved the problem, especially after a month of working.