LifeSentry from LogicMark is the ultimate Personal Emergency Response System. As the world's smallest two-way voice communicator, one can push the button on the pendant from anywhere in and around their home and be talking to a central monitoring station operator in seconds. For years, such systems required one to shout across the house to speak to the central station operator. LifeSentry puts the speakerphone right in the pendant. Up to 600 feet of range - it covers your whole house and into the yard. Uses Contact ID protocol.