| 摘要 |
An electronic control center comprising part of an intrusion (burglar) alarm system, the control center being hermetically encapsulated in a mass of hard plastic (in lieu of the conventional steel cabinet enclosure) for purposes of economy and, significantly, to protect the control center from tampering and attack by an intruder. The control center is very small and presents a single multi-conductor cable directed way from the control center to the remainder of the alarm system including the sensors. The multi-conductor cable leading to the control unit includes a positive supply conductor, a negative supply conductor, four input conductors, one output conductor and one output monitor conductor for monitoring the continuity, during the day time, of the foil on the windows and the trap wiring (lacing) across skylights, air conditioning ducts etc. If any of the input conductors, the output conductors or the positive supply conductor is cut, while the system is activated, an alarm will occur. If the foil monitor output conductor is cut, the foil monitor buzzer will be disabled. In addition to the specific circuitry of the control center, light emitting diodes (LEDs) are imbedded in the protective mass of plastic and connected to the circuitry to respectively indicate the current status of the system per se and various areas of the system under surveillance. This is also important in troubleshooting and in determining whether the system is functioning correctly.
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