Two things I've learned.
1. Don't get "cable phones" or "internet phones." cause they use modems that require a 120 volt plug to be working. Regular phones work in outages.
2. Get a solar charger for a cell phone.
Thats what I replaced my land line with as my wife just had to have a home number. The cable modem has a decent sized battery inside it and I've had it unplugged for up to an hour now while remodeling the basement and its stayed powered up.