Internet can go down, no third party VoIP is going to work - CDV most likely will!
CDV is backed up by battery - my modem is not. No modem - no HSI - no VoIP/ CDV doesn't need modem or internet. CDV does work in a power outage.
Hold the phone! Let's get the facts right.
I have a UPS on my Comcast modem and third-party ATA. When the power goes out, I'm still working.
CDV needs the eMTA ... what do you think that is!!!
What do I think it is? An eMTA. There is no UPS here, the ARIS eMTA has it's own battery - just like my laptops. The eMTA does NOT power anything else - not even it's own HSI modem!