Abstract: A method for ensuring that modules to be connected to an apparatus comprising a processor are of a specific type, includes providing these modules with a code circuit capable of outputting one or more code words on request. When a module has been connected to the system, the processor of the apparatus reads one or more of the code words from the code circuit of the module, compares the read code word or words with reference code words stored in the apparatus, and rejects the module if the read code word or words do not correspond to the reference code words. A large number of different code words are stored in the code circuit of the specific type, and the code circuit is moreover adapted such that a code word can be output correctly only after the lapse of a prefixed period of time, which is considerably longer than a normal output time determined by the implementation of the code circuit, after a previous output of a code word.

Abstract: A method for ensuring that modules to be connected to an apparatus comprising a processor are of a specific type, includes providing these modules with a code circuit capable of outputting one or more code words on request. When a module has been connected to the system, the processor of the apparatus reads one or more of said code words from the code circuit of the module, compares the read code word or words with reference code words stored in the apparatus, and rejects the module if the read code word or words do not correspond to the reference code words. A large number of different code words are stored in the code circuit of the specific type, and the code circuit is moreover adapted such that a code word can be output correctly only after the lapse of a prefixed period of time, which is considerably longer than a normal output time determined by the implementation of the code circuit, after a previous output of a code word.

Abstract: A method for ensuring that modules (3, 4) to be connected to an apparatus comprising a processor of a specific type, includes providing these modules (3, 4) with a code circuit (6, 7, 13, 21, 24) capable of outputting one or more code words on request. When a module has been connected to the system, the processor of the apparatus reads one or more of the code words from the code circuit (6, 7, 13, 21, 24) of the module, compares the read code word or words with reference code words stored in the apparatus (2), and rejects the module if the read code word or words do not correspond to the reference code words. A large number of different code words are stored in the code circuit (6, 7, 13, 21, 24) of the specific type, and the code circuit is moreover adapted such that a code word can be output correctly only after the lapse of a prefixed period of time, which is considerably longer than a normal output time determined by the implementation of the code circuit, after a previous output of a code word.