| 摘要 |
PROBLEM TO BE SOLVED: To inexpensively provide a location detecting system of a person who carries a portable telephone. SOLUTION: Infrared indicators 4 output their own identification information as an infrared signal. When an infrared receiver 6 receives the identification information, the identification information is transferred from the receiver 6 to a portable telephone 5. Then, the telephone 5 transfers the identification information to a PHS base station 1. Furthermore, the identification information is transferred to a location information processor 3 through a PHS exchange 2. The processor 3 specifies the indicator 4 based on the identification information and as a result, can specify the location of the telephone 5 which can receive infrared rays from the indicator 4.
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