METHOD FOR DETECTING OUTSIDE OF PAGING RADIUS IN PRIVATE BRANCH RADIO PAGING SYSTEM

PURPOSE:To inform a receiver carrier staying outside of a paging radius from a transmitter of that the carrier stays outside of the paging radius in the radio paging system (pocket beeper) small in power conservation and used in a private branch. CONSTITUTION:The transmitter 3 is added with a timer 7 and when a next paging is not executed in spite that a fixed time T passes after paging the receiver 4, the transmitter 3 transmits an invalid signal Y which does not included the paging signal X of the receiver 4 and provides the receiver 4 with a timer 8 to monitor that the transmitter 3 is transmitting. When the power supply of the receiver 4 is activated the timer 8 is reset to start a reception operation and when the receiver 4 receives the paging signal X of its own, the receiver 4 executes call incoming operation and resets the timer 8 at the same time. Even at the time of receiving the paging signal X and the invalid signal Y of another receiver 4, the timer 8 is reset and at the time of receiving none of the three signals even after a time (T+DELTAt) passes, the receiver 4 judges itself to stay outside of the paging radius.