As a long time (6 years) and now former cable modem owner I can assure you a UPS on the modem is not going to be much help. After any kind of storm the whole cable service is down for a day or two and the "data" won't be back for a week or more after they get the TV going.
I finally got frustrated and took the slower DSL since when averaged against 12 hours of "zero", .9-1 mbps is faster than the 1.6-1.7 I got from the cable 6.5 days a week. (and totally dead for days after a storm).
Cable would have to actually have to work for a week or more without an outage before I would ever consider dumping my POTS phone for VIOP. So far I have not seen it. I do hit it pretty often since the weather station at my house updates my web page once a minute. I can look at my log and see when it is down. I reported this to Comcast and they just blew it off. Their definition of "down" is you didn't swap ONE packet in 24 hours.
I sat their modem on the front porch in the DSL modem box and told them to come get it.
I hear 'ya there Greg, I hear ya there. If my father didn't work for Es Comcastico, the cable modem in my closet would be a DSL or FIOS modem, whenever Verizon gets their fiber in this section.
My aunt and uncle (one of the head engineers for all Comcast systems in NJ and PA) have CDV, Comcast Digital Voice. They blame our old fashioned "two copper wire" service when their phone doesn't sound good. My dad and I always tell them "Don't fix what ain't broke."
Ian A.
