As a retired communications engineer with over thirty years experience both here and abroad, I must say that not all communications lines are the same even within the same company or area. Part of this is the technology used to provide service. For instance you may be served via land line all the way back to the central switch, by carrier, by fiber optic, or any combination of systems. You may even be on a shared line with other people, i.e. the old party line. Fiber systems cannot transmit power. Glass fiber is an insulator. The small power systems designed for fiber optic systems are supplied by the commercial power company on the subscriber's end. Those remote sites have backup battery systems and contingency dispatched remote generators. But if a large area is without power for very long or if flooded, fiber systems will fail as well as the power to energize remote LED lights.

Most telephone companies pull the heat coils at the Central Switch when a subscriber disconnects their phone service, so no power or dial tone reaches them. If they want service reconnected, they must find another way to reach the phone company. There are not enough lines yet or will there ever be to dedicate to every residence. That is how communication engineers make their money.