Yup! You want an Analog Telephone Adapter (ATA). That's a box which takes Ethernet in, and gives you one or more FXS ports. (An FXS and an FXO port are simil

Yup! You want an Analog Telephone Adapter (ATA). That's a box which takes Ethernet in, and gives you one or more FXS ports. (An FXS and an FXO port are similar, but the FXS port is the one which provides the current that powers the phone, generates the ringing signal, etc.) It's important to note that other than call routing, the ATA has to do almost everything the phone company would do. The ATA provides any Caller ID, for example. It provides call-waiting, or 3-way conferencing. If you want to use a rotary phone, you'll need one that handles pulse dialing. Your ATA will use SIP to connect to a VoIP provider. Some support using multiple SIP accounts (especially if the ATA has multiple FXS ports.