Intruders can use several tactics to disable alarm systems, some of which can be quite sophisticated. With the proper understanding, there are ways to combat such attacks while maintaining the safety and security of the subscriber. In my book, The Alarm Science Manual, I address the most common attacks and offer tips on how to deter such instances.
Cutting Phone Lines
Many present-day alarm control panels are equipped with an internal digital alarm communicator transmitter (DACT). DACTs allow the alarm system to communicate with the central station via the subscriber’s existing telephone lines. In turn, the operators at the central station will notify the police or fire department of the alarm type, the zone(s) affected, and other relevant information.
While this technology revolutionized the alarm industry decades ago, it is passive, meaning it cannot notify the central station of a burglary or fire until after the alarm has been activated. Transmission of all alarm events from a DACT requires system connection to the existing telephone lines at the premises, and if the telephone lines are cut by the criminal prior to entering the facility (as they often are) the digital dialer will be unable to dial the central station for appropriate response.
To deter these attacks, subscribers can take a number of steps. First, they should treat phone and meter rooms as mission-critical areas and secure them appropriately. Securing these areas, perhaps with electronic access control and incorporating them in with the security system zones or points of detection, is a must. CCTV surveillance of these rooms or areas can be useful but should never be the primary means of security, as video might not capture the actual tampering. Most importantly, anyone working on any system in the phone or meter room should be personally supervised by security personnel.
In addition, alarm contractors can provide a system that will poll the telephone line(s) periodically or continuously to ensure their operability. Depending on the technology being used, if a change of state occurs, such as a cut phone line, police or security personnel can be dispatched by the central station to investigate. In addition, the subscriber might consider wireless backup communications, such as long-range radio or cellular.