said by qworster:V-Rads also can supply home voice phone power during power outages-and eventually that part of the V-Rad will be powered by the batteries located in the C.O. via copper pairs. Already Verizon has decided that they will NOT replace batteries in the UPSes they have provided for FiOS-so once the batteries in yours dies you're SOL. Of course, this also assumes that your phone doesn't require AC power to work-which is why I maintain POTS service and one corded phone at my house.
The batteries in the FiOS UPS are replaceable and not expensive. As was reported here nearly a quarter of homes no longer have landlines. I will add to that many landline phones are now portables and or have answering machines that have power supplies or chargers that plug in to AC power. Sooner or later AT&T will ask to be relieved from the responsibility and unnecessary expense of providing battery power from their COs.
