Abstract: A security system for determining intrusion status in a defined area. The system uses a sensor unit, a transmitter, and a receiver. The transmitter sends a unidirectional repetitive coded signal to the receiver. The receiver is capable of receiving the signal, decoding it and displaying the intrusion status to a display. The transmitter uses a novel electric connection and orientation in which the sensor and status decoder is electrically connected to a detection memory, an encoder and transmission control unit is electrically connected to a status collector, and a radio frequency transmitter is electrically connected to an encoder and transmission control unit. The unit provides sophisticated intrusion status detection based on the combination of the parts, organization and electrical connections. The system avoids false alarms due to the unidirectional and repetitive coded signal which is sent to and from the transmitter to the receiver.