Cordless Phones (recommended)
Simply connect a cordless phone base to the ATA. Now you can place the available handsets conveniently around your home.
WiFi Extender (with Ethernet port)
If your internet router is tucked away (basement corner, closet), you may loose access to your cordless phone base. In the situation, you can use a WiFi extender. This device picks up your existing home WiFi and provides you an Ethernet port, so you can connect your ATA. The WiFi extender can then be placed anywhere in your home that you wish to place the ATA.
Powering Jacks in Your House (not recommended)
Powering jacks in your house is not a VoIP Much supported configuration, but is possible.
There are several articles on how this can be done... here is one of them:
Remember, never connect your ATA to a powered phone jack. Traditional phone companies sent approx 50 volts of power over their lines, then you short out your line, burn out and damage your ATA.