Abstract: A fibre-optic splice case has a support for a sealed box which contains a splice connection strip that connects together the ends of two optical fibres from two separate cables. The box is a sealed assembly having a centre of symmetry. The two cables are connectable to the box. The box has a cylindrical support with a central drum and a coaxial outer wall defines therebetween a housing in which the two cables are unreeled or reeled-up in order to deliver or take up a length of cable sufficient to allow the splice to be made. The box also has two separate straight sides each lying substantially in an extension of the other. The straight sides tubular passages are provided for fixing the ends of the two cables. The ends of these straight sides are joined with bottoms of circular overall shape, giving the box a cross-section in the form of a snail-shell.

Abstract: A process for controlling communication between a first and a second smart card using key-based cryptography is provided. In the disclosed process, a first identity code is stored in the first smart card and a second identity code is stored in the second smart card. The smart cards are customized by writing into each of the smart cards an identical group secret key and respective algorithms for processing the identical group secret key and the first and second identity codes stored in the first and second smart cards, respectively. The smart cards are used by transmitting the first identity code to the second smart card, transmitting the second identity code to the first smart card, and calculating using the respective processing algorithms stored in the smart cards, first and second session keys for the first and second smart cards, respectively.

Abstract: Device and process for securing the transmission of telecopies or faxes and a secured telecopier or fax unit having such a security device. The device incorporating a user interface (16) permitting the establishment of a dialogue therewith and a security module (17) permitting the production and checking of digital signatures and preventing replay. The invention also relates to a fax unit including such a device and to a process for securing the transmission of faxes.

Abstract: An add-drop multiplexer includes a first photodector (14), which receives informations in optical form, some of which are to be supplied to users addressees or recipients chosen from among N users addressees or recipients associated with the wavelengths L1, . . . , LN, whilst the other informations form an output flow at wavelength LO, a second photodetector (16) receiving in optical form informations to be inserted in said flow, a tunable source (18), which converts the signals from the first photodetector into optical signals of wavelengths chosen from among LO, L1 . . . LN under the control of control unit (20) and as a function of their destination, another source (22), which converts the signals from the second photodetector into optical signals of wavelength LO, a coupler (24) connecting the sources to N+1 filters (f0 . . . , f3) only respectively permitting the passage of LO . . . LN. Application to optical telecommunications.

Abstract: A process is provided for authentication in a data processing system using a data processing terminal having a programmable memory. The terminal supplies to a server an identify code (ID), the server checks the identify code, and in the case of agreement, supplies a random number (ALEA-A) to the terminal. The terminal encodes the random number using a signature algorithm (B) defined by a secret key (SID), and supplies a first signed random number (ALEA-S) to the server, which applies a signature checking algorithm (T, B, C) to the number (ALEA-S). The identity code and an encrypted secret key (KID) are written into the memory. The secret key (SID) used for the signature of the random number is determined using a decrypting algorithm (INVA) using the encrypted secret key (KID) and a password (MP) supplied by the terminal user. Particular utility for the present invention is found in the area of data processing, although other utilities are also contemplated.

Abstract: A process and apparatus for measuring the resemblance between sound samples incorporating a learning phase and a test phase, each having a digital acquisition and preprocessing stage, an order p acoustic analysis stage and a p.times.p covariance matrix calculating stage with respect to the resulting vector signal, the learning phase also having a reference X covariance matrix inversion stage and a stage of storing the thus obtained matrix X.sup.-1 in a dictionary, the test phase incorporating a stage of multiplying the covariance matrix of test Y with the reference matrix X.sup.-1, a stage of extracting all or part of the p eigenvalues .lambda.k of said matrix product and a calculating stage using a family of functions f, called generalized sphericity functions, so as to obtain a digital value measuring the resemblance between the considered test sample and the reference samples of the dictionary.

Abstract: A process for broadcasting conditional access programs which permits a progressive access. Scrambled program data is transmitted along with partial access checking messages and complete access checking messages such that subscribers having a partial access right may descramble portions of the scrambled data corresponding to information regarding only the identity of the conditional access programs, and subscribers having a complete access right may descramble the remainder of the scrambled data and view the conditional access programs. The conditional access programs may be television pictures, radio programs, or data broadcasts.

Abstract: The invention relates to a memory cell for a static associative memory comprising two arrays of transistors, a first array having a data storage function and a second array having a comparison function between the stored data item and a data item applied to the input of the cell, the comparison result being obtained on a selection line S, in which the second array (T1,T2,T3,T4) of transistors is partly formed by the transistors of the first array (T3,T4,T7,T8,T5,T6). The structure of the cell thus has reduced overall dimensions compared with known structures.

Abstract: A process for the production of thin film transistor with a double gate and an optical mask consisting of depositing a conductive source and drain layer on an insulating substrate (31), producing photosensitive resin patterns fixing the location of the source and drain (34), etching the conductive layer, depositing on the structure obtained an opaque metal layer for forming the lower gate (42), carrying out thermal contraction of the resin patterns, depositing in isotropic manner a preferably a-C:H layer (39), dissolving the resin patterns, depositing a semiconductor layer (44), an insulating layer (45) and then a conductive layer (46) for producing the upper gate of the transistor and photoetching the stack formed by the conductive layer, the semiconducting layer and the insulating layer in order to fix the transistor dimensions and passivate the structure obtained with an electrical insulant (48).

Abstract: A process for the transmission and reception of scrambled conditional access programs, which are synchronously transmitted with entitlement control messages (ECM), with a reduced program switching time. The entitlement control messages (ECM) have check words, which are changed after a period of time called a phase, for descrambling the conditional access programs. The process includes transmitting main check messages (ECMp) for a main access program at a first frequency (Fp) and transmitting secondary check messages (ECMs) for secondary programs at a lower, second frequency (Fs). The secondary check messages (ECMs) are transmitted between two successive transmission of the main check messages (ECMp) such that all of the secondary check messages (ECMs) for each of the secondary programs are transmitted in a single phase. Therefore, a check word for any program is quickly acquired and program switching time is reduced.

Abstract: An interactive optical transmission system including a transmitter assembly (EE) with a FSK DFB laser (10) and a receiver assembly (ER) having the same type of DFB laser (20) and functioning as a photoreceiver. In order to make this system interactive, the receiver (ER) is provided with a channel selection circuit (40) able to supply a current which will place the laser (20) of the receiver assembly (ER) well above the threshold and make it function as an amplitude shift keyed transmitter. The beam transmitted by said laser (20) will raise the optical transmission line (FO) to the transmitter assembly (EE). An amplitude demodulation (48) will make it possible to restore the selection code and control the appropriate information channel (S).

Abstract: This transistor incorporates at least one first stack of semi-conductor conduction layers and at least one second stack of semiconductor layers with a single, highly doped thin film within the second stack giving it the character of a mobile electric charge donor, superimposed and supported by a substrate as well as at least two potential barriers located in the second stack on either side of the doped thin film in order to reduce the concentration of carriers in said second stack a metal gate resting on the second stack for modifying the concentration of carriers of the charges in the first stack, two ohmic contacts being placed on one of the stacks, on either side of the gate and serving as the source and drain.

Abstract: A bipolar transistor comprising a semiconductor substrate, of a first conductivity type, a retrograde well serving as the collector and having a second conductivity type opposite to the first, a base active region having a first conductivity type, a region serving as an emitter of the second conductivity type, the regions being bordered on either side by insulating regions. According to the invention, the transistor includes at least one second conductivity type zone serving as the collector contact, located in a region of the retrograde well at a distance from the base zone and extending away from said base zone no further than level with the insulating zone. The invention is applicable to making BI-MOS or BI-CMOS circuits.

Abstract: Method for making an integrated guide/detector structure made of a semiconductive material.

Abstract: A process for fabricating a semiconductor device using local silicide interconnection lines make it possible to fabricate an integrated circuit having a plurality of electronic elements disposed on a semi-conductor substrate. The electronic elements are formed on the substrate such that they are grouped into a first region and a second region adjacent to the first region, each of these regions having predetermined conductivities. The first region has a layer of dielectric material disposed upon it with at least one capacitive element disposed on the dielectric layer. The capacitive element includes a first electrode layer and a second electrode layer. The second region has at least one double junction metal-insulator semi-conductor field effect transistor (MISFET) located therein. The MISFET includes at least three regions, a gate region and two active regions, a source region and a drain region.