Well yeah. I have a battery backup dedicated to the networking equipment including the phone line to Ethernet converter. What really shuts the phone down is when the cable goes out.One big difference is copper wire does not need a power source in the home. VOIP needs an emergency power source in the home in the event of power outage and even that might not be enough for some systems…
Because of cell phones we don’t really need a “land line” connection anyway.