I've been installing the DS2000's for several months, and have run into my first serious issue that's driving me nuts. Installed the unit last Thursday. It was the 80098 package and 4 port mail [Linked Image from sundance-communications.com] All was well until this morning, when calls were not ringing reliably. After replacing the trunk card, cable, demarc cabling, and swapping slots, I have the same issue. You can call out on all four lines, and if I hook up his old panasonic 4-line phone in parallel, when IT rings, you can answer the call on the NEC by pressing the proper line button. Should I be looking at the P.S. or CPU as well as the trunk card as the culprit? If the voltage can drive my buttset ringer and the other phones, the NEC should get it. Mind you this all worked until this morning.