Neighborhood home security system

摘要: A backup security system for the telephone company lines of a protected home located in neighborhood which all homes have a.c. supply connected to common power transformer. The home, addition being provided with conventional system, is line-cut monitor, PWM transmitter, and conflict avoidance circuit. When monitor senses that been cut by an intruder, it signal gating alarm from transmitter impresses as high frequency signals on neighborhood. neighboring receiver, automatic telelphone communicator. receiver responds provides digital communicator causing seize send message informing central station intruder has broken into home. circuit enables therein impress only when there absence any other