Cable anti-theft common sense

Update:30 Oct 2017

   1, power carrier communication monitoring system sec […]

   1, power carrier communication monitoring system security
Power carriers are a concept derived from the interdisciplinary of power and communication. The power carrier communication method uses the signal transmission means in the wire and cable anti-theft system to load the detection carrier signal on the cable of the detection range. The alarm device of the monitoring center is connected with the carrier signal on the monitored cable. Once the cable outlet section leads to the signal transmission interruption , The alarm can not receive the signal will automatically alarm, play a warning role. Power carrier communication method is currently the most widely used as a means of anti-theft, because it is on the cable to be monitored on the transmission of carrier signals, no additional lines, so the power carrier communication method has easy installation, detection of hidden, Up to several kilometers) and so on. However, because the cable is stolen only when the alarm can not deter the criminals, and can not video evidence, a single power carrier communication is facing an integrated, systematic challenges.
2, capacitance detection monitoring system security
The principle of the capacitor detection method is to first use a pair of empty cable short-circuit cable terminal, the other end of the alarm connected to the multi-harmonic oscillation, when the cable is working properly, the alarm oscillator does not produce vibration; when the cable outlet section, vacant The cable becomes a simple capacitor, the oscillator will output the signal, causing the alarm, and the oscillator output signal frequency with the cable cut off the location of different changes.
3, current detection monitoring system security
The system detects the cable current in the cable circuit to determine the integrity of the cable system. That is, when the cable is working properly, the detection system does not respond; when there is no current transmission in the cable, the detection system will start the alarm system. The current detection system can not be used for voltage and no current cable anti-theft system, such as subway tunnel or highway tunnel blower power cable. In addition, the system can only be in the circuit system all branch cables are cut off, the alarm (because the cable branch all open, the cable loop current is zero). So the current detection monitoring system there is "no warning" hidden.