I have a 61c with a pri which was dropping calls. I replaced it. It turns out problem was on far end. I decided to put back the old card, but when I did the system crashed. I made sure to dis dch in ld 96, dis msdl in ld 48,disl l in ld 60 & card was toggled to dis when replacing. Now mmail will not reboot & every time I put a new card in I drop the switch. This is a call center.