The most important part of an alarm system is how it communicates alarms to the central station. Most alarm systems use phone lines for communications, the same phone lines that you talk on. If the phone line is not working or gets cut then your system will NOT be able to communicate to the central station. How to physically protect a location is simple, door contacts, motion detectors, glass break detectors, etc. You can call any alarm company and you will get the same thing. If your system cannot communicate alarm signals to the central station when needed, then you have nothing.