| 摘要 |
PROBLEM TO BE SOLVED: To provide a selective call buoy with a theft preventing device not responding to a theft signal even when the buoy receives the theft signal. SOLUTION: The buoy is composed of: an antenna 1 for receiving a selective call signal from a base station; a reception section 3; a switching device 2; a signal selection section 5; an auto keyer section 6; and a transmission section 6. The signal selection section 5 is provided with a plurality of filter circuits 5a, 5b, 5c, 5d, 5e and a signal detection control section 7. A plurality of the filter circuits 5a, 5b, 5c, 5d provide an output of a signal when the selective call signal includes a unique selection number. The filter circuit 5e responds to the selective call signal when the selective call signal includes other unique selection number than the unique selection number. When the selective call signal is the theft signal, the filter circuit 5e masks signals of the filter circuits 5a, 5b, 5c, 5d responding to the unique selection number and the signal detection control section 7 outputs no response signal. COPYRIGHT: (C)2004,JPO
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