| 摘要 |
A system for locating persons within a limited area or a building and alerting a central unit comprises a cellular telephone installation with a number of portable telephone terminals and a number of stationary transceiver units set up within the area or building. These transceiver units each cover part of the area or building and are connected to the central unit, the central unit receiving information from the transceiver units relating to the telephone terminals present within the part of the area or building associated with a transceiver unit. Each telephone terminal is provided with an alert button which emits an alert signal when the telephone terminal is operated. The central unit is provided with a display device and is programmed in such a way that, for each telephone terminal registered in the system, on reception of an alert signal, the location of the telephone terminal is indicated on the display device and an alert signal is emitted.
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