Electronic security system

摘要

An electronic security system includes a detector (S1, S2) for detecting unauthorized entry of a trespasser into a predetermined outdoor area (A1) or an indoor area (A2) and for generating a detection signal (d1 or d2) indicative of the entry of the trespasser. A mode setting circuit (2) is operated by an input keying operation to select one of an alert mode, in which any possible entry into the predetermined outdoor area (A1) or the indoor area (A2) is monitored, and a non-alert mode in which the possible entry into the predetermined outdoor area (A1) or the indoor area (A2) is not monitored. A control unit (4) preferentially transmits a warning through a telephone line (1) when it receives the detection signal (d1 or d2) generated during the alert mode, but transmits no warning during the non-alert mode. A warning device (12) acknowledges dispatch of the warning. A priority selector (8) is used and operates when the warning is preferentially transmitted to the telephone line (L) for switching from the preferential transmission of the warning over to a normal telephone communication by means of an input keying operation performed by an operator informed of the warning.