Abstract: An electronic intrusion detection system for monitoring environments having at least one electronic sensor responsive to movements occurring in the environment and adapted to modify at least one characteristic of its electrical output in response to the presence of a moving body in the environment. An alarm is signaled when the modification meets a predetermined condition. A transducer is provided for continuously converting the modification of the output from the electric sensor into a signal that can be perceived by a human being. An alarm control unit connected to the alarm and transducer forwards the signals to the surveillance personnel through a telephone line.