We have a CS1000 rls 7 with loop 0, 4 and 8. In loop 8 the MGC card displays the loop number and it seems to be working but when we program a tn for a digital set the phone comes up but we are unable to hear dial tone and cannot dial any extensions or outside numbers. We tried a different cabinet but the same issue. Could this be a bad MGC card? Any assistance will be appreciated.