Cable modem frequency?

You can not connect a DSL modem/Router to a Cable modem the are two completely different devices. Basically one speaks English the other speaks Mandarin and neither has Rosetta Stone.

_`you can't lose your connection to the server easily. _`you can check your server-client rigth away if there is coonection problem accure.

The cable modem can be faulty, check with you service provider

Ther are two types of VoIP, one that requires VoIP modem and one that is through web user interface account. It doesn't matter whether it is a cable modem or an ADSL modem.

Yes, you can.