Ok, this must be drastically different than A.T.&T.

It is important to note that all land line telephones are run on "battery" 48VDC. The grid electric supplies the charge to the batteries that power the system at all times.

Between the military and building homes, I worked for A.T.&T. They have added stand-by capacity in all of their generators for 7 days. Then you are purely on battery. As each central office (CO) goes to battery, you have 24 hours.

Each Pair Gain (fiber to copper, so it can be used in the home) has 4 to 8 hours battery capacity. These must have a generator brought out to them.

Cell sites generally have a small generator on site, or someone brings one out. Their battery capacity for the radios is about 8 hours, but this battery will not run the air conditioners. Because of this the radios get hot and shut down.

I could go on a long course regarding how the civilian land lines work here in the states, but: 1 too much time; 2 off topic.

Suffice it to say, a long power outage will kill cell sites before land lines due to availability of portable generators. Maybe I think this one thru, and start a new thread elsewhere on the forum once I wake up fully.