| 摘要 |
The invention relates to a security device intended to be connected to a processing unit for an audio/video signal. This device comprises means to decrypt an audio/video stream, an interface of the ISO 7816 type and an interface of the USB type. It is characterised in that it includes a clock frequency detection module connected to a clock input of the 7816 interface, this detection module comprising means to distinguish the input frequency according to at least two different frequency ranges, one of said frequency ranges activating the USB function. The invention also concerns a process for processing an audio/video signal by means of a security device comprising means to decrypt an audio/video stream, an interface of the ISO 7816 type and an interface of the USB type. The process is characterised in that it includes the following steps: sending of a clock signal to a clock input of the ISO 7816 interface according to a preset frequency; determination of a frequency range to which said preset frequency belongs; determination of the operating mode of the security device according to the determined clock frequency range; processing the data according to the determined operating mode.
|
