Abstract: A tracer-gas leak detector includes an analysis unit and a primary pump whose inlet is connected to an inlet orifice of the detector via a first pipe equipped with a first valve. A secondary pumping set has an inlet connected to the analysis unit and an outlet connected to the inlet of the primary pump. The primary pump is a dry pump. The secondary pumping set includes two secondary pumps of the mechanical type separated from each other by a second valve. The secondary pump that is proximate to the dry primary pump is the second secondary pump and includes a dynamic seal stage at its outlet. A second pipe connects the inlet of the second secondary pump to the first pipe downstream from the second valve. A third valve is disposed on the first pipe between the outlet of the second secondary pump and the junction where the second pipe meets the first pipe. The third valve is controlled by a pressure sensor placed at the inlet of the second secondary pump.

Abstract: A switching center of the invention includes a service access exchange and a control point which are interconnected by an interconnection multiplex link. The exchange is connected to base station controllers via first multiplex links and to the public switched telephone network by second multiplex links which also convey signalling relating to a permanent file, relating to a temporary file, and relating to other switching centers. The exchange sets up semipermanent links between the interconnection multiplex link connecting it to the control point and both the first multiplex links for the purpose of interchanging signalling, and to the second multiplex links for interchanging signalling with the permanent and temporary files and with other switching centers.

Abstract: An interactive call is set up by a method including the steps of: emitting a message from the terminal to the connection network defining the resources required for all of the connections and for all the periods of the call, and emitting a message from the connection network to the terminal indicating that the network possesses such resources for at least one call. During each interactive call, prior to each new period requiring different resources, and for each connection of the call, the method further includes the steps of: emitting a message from the terminal to the connection network indicating each connection that is going to be necessary during the new period and indicating the resources that will be required for the connection, emitting a message from the connection network to the terminal confirming that the resources have been reserved by the network, and storing in the terminal data to be transmitted over the connection network until the terminal receives the message.

Abstract: A handover method for a cellular radiotelephone networks in which, a call having been set up with a mobile via a first transceiver of a first cell, the handover consists in handing over to a second transceiver of a second cell and in switching in the mobile from the first transceiver to the second transceiver. The switching instruction interrupts the call in a defined cut-off time interval. The instruction to hand over the call is given under conditions such that the interruption of the call which may result from the handover operation occurs during the defined cut-off time interval.

Abstract: A device for inserting information bits into a specific frame structure essentially comprises an elastic memory whose capacity is designed to contain at each time defined by a reduced insertion bit rate D2/N a variable number of bits of words read in a buffer memory written at a reduced bit rate D1/N not yet inserted or not yet reinserted in the outgoing frames, this number varying according to justification commands generated previously, devices for selecting bits contained in said elastic memory for insertion or reinsertion in the outgoing frames, and devices for temporarily blocking the buffer memory read clock if the number of bits to store in the elastic memory exceeds a predetermined limit value.

Abstract: A smart card reader comprises contact members and card guiding and positioning devices including a guide corridor and an end of travel positioning abutment. The combination establishes electrical connections between the contact members and conductive lands of a card inserted into the reader until it bears against the end of travel positioning abutment. The end of travel positioning abutment is retractable. The card guide corridor is open at its inner end to the rear of the retractable abutment.

Abstract: A gas/liquid mixture passes through a duct in which a filter device is interposed, the filter device being disposed such that its outlet duct is essentially vertical. The outlet duct opens out into a collecting enclosure placed above the filter device. A side outlet duct from the enclosure is disposed below the level of the liquid collected in the enclosure, a top portion collecting the gas given off above the level. The top portion communicates with the inlet of a jet which reinjects the gas into the outlet flow so as to form a homogeneous gas/liquid stream. The invention may be used, in particular, in the lubrication circuit of a vacuum pump having vanes and oil seals.

Abstract: The energization current of an indium phosphide or gallium arsenide double channel semiconductor laser is confined within a laser stripe by near and far current blocking arrangements. The near current blocking arrangements are formed by a blocking junction formed in two lateral channels delimiting the stripe. The far current blocking arrangements are formed by an iron-doped semi-insulative layer grown epitaxially before the lateral channels are etched. A particular application is to the fabrication of pump lasers used in optical amplifiers of optical fiber links.

Abstract: The side surface of a ferrule (16) carrying a polarization-maintaining option fiber (10) has a projecting substantially dihedral-angled portion (17, 19) engaged in a complementary re-entrant substantially dihedral angled portion (22, 24) formed in a ferrule receiver (20). The invention is particularly applicable to making a laser-emitting head for an optical fiber telecommunications network.

Abstract: A circuit for detecting locking of a digital phase locked loop for locking the phase of a digital outgoing signal as provided by the loop to the phase of a digital incoming signal received by the loop, wherein the phase locked loop includes a detector for detecting the phase difference between the incoming signal and the outgoing signal, and the output signal from the phase difference detector has transitions of a first type in coincidence with transitions of a given type in the outgoing signal, and transitions of a second type in coincidence with transitions of a given type in the incoming signal, the circuit including locking detection means for detecting locking, the locking detection means themselves including means for sampling the output signal from the phase detector by those transitions in the outgoing signal that are of type opposite to the given type, means for storing groups of consecutive samples, comprising not less than three consecutive samples, and means for detecting the instant at which, for

Abstract: A method for controlling the operating mode of a digital phase-locked loop including a counter controlling incrementing or decrementing of the frequency of a digital clock signal internal to the loop is such that, the input signal of the loop being present intermittently, with random phase from one appearance to the next, the control method comprises, in this order, the following steps:detecting the appearance of the input signal,selecting a relatively low capacity of the counter to enable relatively fast synchronization of the loop,detecting synchronization of the loop,selecting a relatively high capacity of the counter to filter relatively strongly any phase variations of the input signal occurring while it is present, this latter adjustment being retained until the next detection of the appearance of the input signal.

Abstract: An electromagnetic seal consists essentially of an oblong metal plate with two bends along two parallel longitudinal bending axes (D1, D2) defining on the plate two lateral flanges (34, 35) inclined relative to a central panel (36), and an central oblong opening (29) which has a width (a) slightly less than the distance (b) between the bending axes so that parts of the central panel situated on the longitudinal edges of the central oblong opening, separated before bending by cut-outs on the transverse edges of the opening and between the bending axes and the central oblong opening, are adapted to form oblique extensions of said lateral flanges in the region of the central oblong opening.

Abstract: A switching element for cross-connect equipment for digital bit streams multiplexed by time-division multiplexing of digital bit streams at different bit rates includes, for each incoming frame transmission medium, a device for extracting from said incoming frames signals constituting multiplexing units to be cross-connected. It further includes for each incoming frame transmission medium a memory for signals constituting multiplexing units to be cross-connected adapted to hold at least N signals where N denotes the repetition period in the incoming frames of the lowest bit rate tributary of the multiplexing hierarchy.

Abstract: An apparatus for evaluating data rates of virtual circuits occupying an asynchronous time-multiplexed transmission path includes a memory in which each virtual circuit is allocated space containing a context defining conditions for evaluating the data rate of the virtual circuit. This context contains a starting time which was the current time as recorded on receiving an earlier cell in the virtual circuit under consideration. Each time a cell is received, the context of the virtual circuit to which the cell belongs is read, and the starting time is subtracted from the new current time, with the time difference established in this way constituting the basis on which the data rate is evaluated, and with repressive countermeasures being initiated in the event of the data rate being excessive. The apparatus further includes device for cyclically scanning the contexts and for incrementing a scan cycle counter in each context during the cyclic scanning, the scan cycle counter having an initial position.

Abstract: A method of tinning tinnable areas of an electronic component package, the method comprising a first step during which additional metal is applied in the liquid state to said tinnable areas, and a following step during which at least one cycle of oscillations about an equilibrium position is applied to the package while said metal thus applied is still in the liquid state, for the purpose of setting up successive and opposite displacements of masses of said metal along said areas in order to obtain a uniform distribution of said metal over said areas.

Abstract: A smart card reader suitable for use in a pocket radiotelephone comprises a case enclosing the other parts of the reader including a printed circuit board and an arrangement for fixing the printed circuit board to the case. A smart card connector comprises an insulative frame carrying spring contacts, a cover for exerting pressure on a smart card and an arrangement for fixing the frame to the cover. The connector cover is integral with the case and the arrangement for fixing the frame to the cover fixes the frame direct to the case.

Abstract: A Roots-type machine is connected to an enclosure to be evacuated via a suction inlet portion, and to a primary pump via a delivery outlet portion. A bellows is disposed transversely in the inlet portion, one end of the bellows being fixed in gastight manner in the wall, and the other end being closed and movable, so that the bellows forms a regulating member for regulating the gas-flow sectional area in the inlet portion. The outside face of the movable end of the bellows is subjected to the pressure in the inlet portion, and the inside face of the movable end is subjected to the pressure in the delivery outlet portion via a rod passing through the wall, and via a channel. The invention applies to Roots-type machines, in particular for automatically regulating the pumping speed so as to match it to the flow-rate of the corresponding primary pump.

Abstract: The converter comprises a memory (SRAM) having first and second ports, a first port management circuit (SPM) connected to the first port, to an incoming synchronous multiplex line (ME) and to an outgoing synchronous multiples line (MS), and a second port management circuit (APM) connected to the second port, to an incoming asynchronous link (LE) via an FIFO type packet memory (M) and to an outgoing asynchronous link (LS). An external command (MF) applied to the port management circuits selects the converter operating mode; in a first mode (M32) each time slot of a frame of a synchronous multiplexed signal is assigned to one communication channel and in a second mode (M1) all the time slots of a synchronous frame are assigned to one channel.

Abstract: A machine of the fluid entrainment or the positive displacement type, such as a compressor or a vacuum pump, in which injection of dry gas is effected in the discharge region of said machine or of one of its stages, wherein said injection is effected in a distributed manner over a surface.

Abstract: A bridge for connecting an IEEE 802.3 local area network to an asynchronous time-division multiplex telecommunication network comprises a part implementing the functions of layer 2.1 of an asynchronous time-division multiplex telecommunication network transmission protocol and a part which is a conventional local area network interface implementing the functions of layer 1 of the local area network data transmission protocol. The circuit is applicable to the transmission of data between different local area networks.