The IPSU2 unit has been beeping indicating that the battery needs replacement. It is my understanding that the IPSU2 unit is only for providing UVerse Voice in the event of a power outage. Is this true? Can I unplug the IPSU2 and still have internet and voice connectivity when the power is on? I can use my cell phone if there is a power outage. This will save me from having to replace the battery.