I set the system clock and the time always changes. It stays within a couple hours (behind). I have rebooted the system, removed it from the ups, verified that it is on a decicated circuit (power), rebooted the system again and still the clock gets off a couple of hours after a few days. I tested the ups and it is good. It is not connected to pri. One trunk card is caller ID that tie to a independent intercom system. Can the system clock be effewcted by the caller ID Trunk incoming call? Does this sound like a software problem? Note :The date is right and the users never witness the phones going out.