| 摘要 |
Transmitting identification codes of fixed units by wireless telephones to a central computer via a wireless switching system. The central computer uses the identification codes to locate the wireless telephones. Since a wireless telephone already has the capability for communicating utilizing a wireless protocol, the only additional cost to the wireless telephone is the ability to receive the transmission from the fixed units. The wireless telephones use a first wireless media for transmission, and the fixed units use a second wireless media for transmission. Further, each fixed unit consist only of a transmitter. The second media maybe infrared or ultrasonic transmission. If the wireless telephone fails to detect a fixed unit, the wireless telephone transmits this fact back to the central computer. This is done so as to determine locations that are not serviced by a fixed unit and also to detect failed fixed units. The central computer maintains a log of fixed units with which a wireless telephone had been previously identified. This allows the central computer to determine where there is a need for a fixed unit or which fixed unit has failed. The fixed units can be battery operated. When the controller controlling the fixed unit determines that the battery is reaching a low state in the fixed unit, the controller transmits this information along with the identification code so that the low battery indication can be relayed to the central computer.
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