we have vonage, and you dont need a special phone but with ours we have a special router that our phone plugs into.

not sure about VOIP with cable providers though.

We have phone service through our TV cable provider (Mediacom), along with broadband internet. Uses existing phone lines in the whole house with no special phones needed.....only thing needed is a special modem for it, which the cable company installs.

Be aware that if electrical power OR TV/internet (cable) has problems, you won't be able to use the phones.

Tracey