If the acoustic sensing fiber cable is cut; FOTAS’ intelligent algorithm informs the user instantly, and displays an alarm user interface. In addition, the acoustic sensing capability of the system will continue to work along the fiber cable, up to the point where the cable was cut. However, if the fiber cable is connected to the system from both ends, one cut cannot isolate the sensing fiber from the system. In that case, only two cuts at two distant points can create a blind spot in the fiber sensing cable that is connected from both ends of course.