Panasonic KX-DT543-W Digital Phone 24 Programmable Line Buttons 3-Line Backlit LCD Display Hands- Free Speakerphone Electronic Hook Switch Works with hte following Panasonic phone systems: Panasonic KX-TDA 50 / 50G / 100 / 200 / 600 Panasonic KX-TDE 100 / 200 / 600 Panasonic KX-NCP 500 / 1000 Panasonic KX-NS100