home security company. With alarm monitoring service from ADT, you can rest assured ADT will always be there to help keep your family and home safe and secure with an exceptional level of home security protection! ADT has a comprehensive network of interconnected command centers strategically located throughout the United States, giving ADT the ability to effectively offer continuous home security alarm system monitoring across the nation. If someone does attempt to enter your home uninvited and triggers protected zone while the alarm system is armed, the ADT monitored home security system sounds, letting the intruder know he's been discovered and is not welcome in your home.