This Tele-Data Guard keeps calls private. The Tele-Data Guard
alerts the user if someone has picked up an extension, when the Tele-Data Guard
is installed on all extensions, the extension you pick up automatically
disconnects the others. Powered by your telephone line, and requires no
batteries or power source. Specs: Green LED alert light, Signals whether line
is in use, Protects faxes and modems from interruption and No batteries
required. TDG028