[CDV] Connectivity during power outage...

I'm considering a Cable Modem for my mother, and running Vonage over it for voice. Also, I'd set up a UPS to make sure voice stays up during transient power outages. BUT: I know that there are in-line amps in the cable system, which are powered in-line. Question: When there's a power outage, I guess these amps go down too, and the signal dissapears? If I power everything with a UPS, the modem might lose sync anyway if all the in-line amps go down? Has anyone experienced this directly? Edited to add topic group category. uid://455626