| 摘要 |
<p>To prevent the use of a device which has been reported as lost or stolen, a blocking code is sent to the device and is processed to prevent operation of one or more pre-defined internal functions of the device. The device includes a digital transmission receiver and the blocking code is transmitted over a digital wireless network. The device is preferably a digital audio broadcasting (DAB) radio receiver but can also be a digital mobile telephone or a digital television receiver. The device may further be embedded into another kind of device, e.g. a vehicle, laptop computer, digital camera or video camera and processing of the blocking code can prevent operation of one or more pre-defined internal functions of this other device. The blocking code may be sent as part of a carousel, in a packet service or in a fast information channel (FIC) in DAB. The code can be repeatedly sent and the device can activate itself at pre-defined times to receive and process any blocking code sent for it. The device may be arranged to acknowledge receipt of the code and may respond with information such as its location. A disabled indication may be stored in the device in such a manner that it cannot be erased by power-cycling of the device. Unlike prior art IMEI blocking systems, where the device is denied cellular network access but is still operable, deactivating internal functions stops the device from being used at all, while still allowing for subsequent re-enabling.</p> |
