Customer FAQs Discover answers to the most frequently asked questions from ADT customers with the click of a button. 1. Do I Need A Landline for My ADT Monitored Security System? When it comes to monitored home security systems, you have a couple choices. You can buy a security system without a landline, or a landline security system. Typically, a security system without a landline uses cellular technology to communicate with the security company's monitoring center. A landline security system uses your home telephone line to reach the monitoring center. ADT monitoring offers both options.Whether or not you need a landline for an ADT monitored home security systems depends on which package you choose. For example, ADT monitoring packages such as the "Basic," "ADT Pulse®," and "ADT Pulse® + Home Monitoring" all require a landline. When your alarm is activated, the security system alerts the ADT monitoring center by using your home telephone line. Should an alarm be activated while you're using your home phone, the security system will take over the phone line and call the ADT monitoring center. As soon as the monitoring center is notified, the security system releases the line so that you may speak with the ADT monitoring center professional. Even if your home phone has call waiting, the ADT monitoring center will be notified.ADT monitoring realizes many homeowners choose to go without a home phone and rely solely on their cell phone. The good news is, even if you don't have a home phone, you can still take advantage of ADT monitoring thanks to CellGuard®. CellGuard® uses cellular technology instead of a landline to communicate with the ADT monitoring center. Some VoIP and digital phone services also connect to the ADT monitoring center. Even if you have a home phone, you may want to consider getting CellGuard® as a backup. Your home phone line will serve as the primary communication line with the ADT monitoring center, but if your home phone service is interrupted or experiences an outage, CellGuard® takes over. CellGuard® helps ensure you and your family never lose connection to the ADT monitoring center.Whether you chose to connect to the ADT monitoring center via home phone or through CellGuard®, you can access 2-Way Voice. 2-Way Voice offers you hands-free communication with the ADT monitoring center the moment your home's alarm or ADT monitored panic button is activated. Using the 2-Way Voice feature you can speak with an ADT monitoring center representative through the microphone built in to the ADT monitoring control panel. The representative can verify what type of emergency you're having and dispatch the appropriate emergency service immediately. 2-Way Voice is an especially helpful feature for the elderly, disabled, or those who live alone. Should they fall or have a medical emergency that makes it impossible for them to reach the phone, they can still get the help they need. Also, should a burglar break into your home and set off the alarm, the ADT monitoring representative can hear and record the incident and notify law enforcement immediately.Whether you choose a landline security system or a home security system without landline, ADT monitoring has representatives at four customer monitoring centers standing by to help you and your family get the assistance you need.