The most important link in your entire security system is often found running exposed along the backside of your home and into the basement - your phone line. If someone were to cut that line, or if a tree limb fell on lines down the street even, your alarm system would not be able to communicate with emergency responders during a crisis. Even broadband phone lines and internet communications can fail when you need them most. That is why Shield Alarm Systems are backed up by radio communication, known as secured monitoring, that functions even when your phone lines are out.