Steve Walker wrote:
Assuming that both the VOIP phone and router need to be powered to make
calls, how are they getting around this? Especially when a severe
weather event could take power out to isolated houses or whole villages
for days, in conditions where the residents can't travel to get help.

https://www.ofcom.org.uk/consultatio...ions-power-cut
summary
https://www.thinkbroadband.com/news/...gency-services