I was wondering if anybody has any idea what it woudl take to be able to have a local voip server that would use a normal land line to call in and out.

I want to hook my land line to a modem on my home linux server and connect that modem to a voip server so that i can connect a voip client on my PC and be able to call (and also use a smartphone with a voip to call using hte land line).

Any idea what it would talk to do that ?