The Network Integrity Systems VANGUARD FOCUS™ Optical Intrusion Detection System utilizes Distributed Acoustic Sensing (DAS) technology to provide long range detection capability along with pinpoint location of any physical disturbances to your critical communications cables. The VANGUARD FOCUS sends pulsed laser light into a single strand of single-mode optical fiber and monitors the Rayleigh backscatter from the reflected light. The Rayleigh backscatter pattern changes with acoustic and vibrational energy. Once the reflected pattern is received, it is processed and analyzed by advanced algorithms to determine the type of event, such as digging near buried conduit, cutting into conduit, and physical handling of the cable. The system will also provide precise location along the cable and monitor the event over time.