Enjoy the freedom of independent living with constant emergency protection. Guardian Alert 911 Personal Emergency Response System requires no monthly subscription or service fees. It works just like a cordless phone on any standard phone line with 911 service and tone dialing. Talk directly through your Pendant to a 911 Emergency Operator at the push of a button. Guardian Alert 911 can be comfortably worn around the neck, clipped on a belt or carried in a pocket at all times. Complete coverage in and around your home (range: 600 ft./183 meters line of sight). Installs in minutes: no tools required. Replaceable AAA alkaline battery (included) lasts 1 year in standby or up to 30 minutes of talk time. Operating frequency: 900 MHz. Not compatible with digital phone service.