Abstract: A communication installation for communal reception of digital television and/or of multimedia data, which receives a plurality of signals emanating from separate sources. The installation of the invention comprises a network linking a multiplicity of descrambler/decoder devices, available to the users of the community, to a local server capable of demodulating the signals received so as to despatch them over the network in the form of a stream of packets of common modulation, with software applications allowing the descrambling/decoding of the signals. Thus, off-the-shelf descrambler/decoder devices of similar designs can process the various signals received.

Abstract: An access trial control device for a card, such as a financial or business transaction card or the like, which is inserted in an access terminal for use and carries a confidential code which is compared with an access code type by the user on the terminal. For each access trial the result, acceptance or refusal, of the comparison is permanently recorded by non volatile memory means in the card. The number of consecutive access trials refused is counted in a counter and is detected by a control circuit which disables the card when such number reaches a predetermined value. Each accepted access trial resets the counter to zero.

Abstract: In a transaction card such as a credit or payment card provided with an integrated circuit for performing and recording the transaction, communications between the card and an access terminal must be coded so as to prevent fraud attempts. An integrated circuit coding device for coding or decoding a message in accordance with a confidential coding key comprises active transistors, and passive transistors, i.e. permanently blocked and/or permanently conductive, interconnected in such a way that observation of such circuit by means of an electronic microscope does not allow the determination of the confidential key which is implemented by the circuit.

Abstract: An arrangement for simultaneously producing signals having a decreasing frequency and signals having an increasing frequency. In this arrangement the signals have frequencies which are complementary relative to the double value of a central frequency. The arrangement includes a pair of voltage-controlled oscillators controlled by signals supplied by a control generator. The arrangement is characterized in that for each oscillator there is provided with a phase control loop and that the control generator is of the digital type designed to supply two pairs of digital signals. One pair is applied to the frequency dividers and the other is applied to the oscillators so as to tune them to such a frequency that they are in the operating range of the phase control loop.Use: Radio-electric transmission of data.