When we sold our old hose we left the security system there so we knew we'd need to purchase a new home security system once we took possession of our new home. We used ADT for the old house, so we decided to go with them again. A rep came to our house and it was a easy process for my husband to negotiate what he wanted.
We use a digital line for our home phone so the components for our package are different than those for analogue lines. We have a wireless 24-monitored security system that operates on our digital line. Our security system came with wireless, heat sesitive motion detectors, front, side, garage and back door contacts (makes a beep sound when these doors are opened), a keypad and two key FOBs that allow us to enable and disable the alarm from inside or outside our home (kind of acts like a TV remote but small in size like a keychain).
The installer walked me through the commands and how to setup the 'zones' on the keypad but I like to use the key FOB instead, its easier! We haven't had the need to take advantage of the 24-hour monitoring (thank goodness!)but a couple of time a year we test the system to ensure that the alarm will go off. When it does, it's so loud it can wake the dead!