I have FIOS. the ONT which convers the optical cable to standard DSL
like is outside on side of house.

The power supply is in the basement with a built in UPS that only
keeps the phone service working but you can plug this unit into a
larger UPS if you want, Doing so will keep the internet part working
too during a outage.

I have mixed feeling about FIOS the internet part works awesome
HOWEVER the phone side is much less reliable than copper and worse the
reps really dont care. We had SEVERE troubles and it took over a month
to get it fixed, the last 2 weeks I called daily and the trouble
effected the entire central office.

I will likely go VOIP it cant be any worse