Plantronics headset phones comes with everything you need including the headset, and a telephone keypad to start using your headset as a stand alone telephone. The base unit plugs directly into the existing telephone jack. Plug the Plantronics headset into the amplifier/keypad and you are ready to start talking! Plantronics headset telephone is not a stand alone headset and will NOT work with your existing desktop office telephones. These headset telephones are replacements for your existing telephone. They requires an Analog telephone line (typical phone line in your home). It will not work with a office digital phone or PBX phone system. Check out the Plantronics T10 or the Plantronics T20, our most popular Plantronics telephone systems.