| 摘要 |
A problem with mobile radio systems is the potentially harmful interference they may cause to other electronic equipment. Such interference can be dangerous and even life-threatening in hospitals and aircraft. Interference to automobile electronic braking systems, air bag actuators, or train system controls are examples of other areas where radio system interference must be prevented to preserve the safety of operators and passengers. The present invention provides a system whereby mobile radios, e.g. cellular phones, can be operated safely in regions where interference could cause serious problems or can be prevented from operating. The mobile radios are provided with a low power mode of operation and are commanded, via their signalling channels, to operate in the low power mode when within range of a low power signal from a base station within a protected area. In some areas where it may be undesirable for the mobile radio to operate, even at low power levels, the base station may broadcast an inhibiting signal which will instruct the mobile radio not to operate its transmitter while in the area.
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