usually come with a wall mounted panel that acts as a communications hub, with a touch screen display that allows you to do everything the app does. The display lets you communicate with a professional monitoring service when an alarm is triggered and view video from any of the installed security cameras. While many systems use wireless components that are installed using double sided tape, some high end systems use components that require professional installation. These soup to nuts systems typically cost considerably more than DIY systems and offer 24/7 professional monitoring, but you may have to enter into a multi year contract and pay a hefty termination fee if you break it. They usually use touch screen hubs thatcontain RF, Wi Fi, Zigbee, and Z Wave radios, allowing them to communicate with and control a multitude of components including door and window sensors, door locks, glass break detectors, indoor and outdoor cameras, light switches, motion and water detectors, smoke/CO alarms, thermostats, video doorbells, and a host of other home automation devices. With a professionally monitored system, when a smoke or intrusion alarm is triggered, an agent will first try to reach you via the two way control panel before calling your listed phone number.