Abstract: A novel packet-oriented multiple path self-routing switching network for switching asynchronous time-division multiplexed packets is characterized in that each switch unit of at least one upstream stage of the switching network includes means for defining an available state in which the downstream switch unit is available for routing packet traffic and for transmitting availability status information to upstream switch units when the downstream switch unit is in that available state, and is further characterized in that each upstream switch unit includes means for receiving availability status information for those outputs leading to a switch unit in the available state, and for prohibiting access to any output for which such availability status information is not received.

Abstract: A multiple path, self-routing switching network for switching asynchronous time division multiplex data cells includes input ports (pi1, pi64 . . . ), output ports (po1, po64 . . . ) and switching elements (TSi1, TSi16 . . . ) arranged in a number of stages of interconnected switching elements, each switching element having inlets and outlets and being constructed to transfer a data cell received at one of its inlets, to one or more of its outlets, according to routing data associated with said cells. Each switching element of at least one stage of the network has at least three outlets, arranged in groups of outlets of one or more determined outlets. Using routing data associated with a data cell received at any one of its inlets, the switching element (TSi1, TSi16 . . . ) identifies a set of one or more of said groups of outlets and to transfer said received cell to an outlet of each group of outlets of the selected set.

Abstract: An elongate body insulated by means of an insulating covering, said covering being constituted by a tape (2) made of synthetic material taped around said body (1) and covered in a layer of varnish (11) made of synthetic material, the body being characterized in that the taping is such that there exists a groove (4) between the free edge (5) of any portion of a turn (3) that is not covered by the following turns and the uncovered surface (6) of the preceding turn, the width of said groove (4) lying substantially in the range 0% to 5% of the width of said tape (2) and being strictly greater than zero.

Abstract: In a method of manufacturing a planar buried heterojunction laser, after etching to delimit a laser stripe in relief on a substrate, lateral layers to surround the stripe are formed by a non-selective growth method not only at the sides of the stripe but also above it to create a parasitic projection. This projection is then removed after separation from the substrate by selective attack of a lift-off stripe which was deposited for this purpose above the stripe prior to this etching. Passages are formed for the attack medium used for this purpose. The invention can be applied in particular to the manufacture of fiber optic transmission systems.

Abstract: The switching element is used for transferring, between X inputs (I1-IX) and Y outputs (O1-OY), cells divided into subcells of which only the first contains information about the destination output(s) of the cell. This switching element includes: a buffer memory (BM) with a plurality (C) of memory locations each having an address (K); and a memory management means (BMMU) for providing (FMLMC) addresses of free memory locations for storing the subcells therein, and for storing (BQ1-BQY, SLM), under the form of linked lists, the memory location addresses used by the subcells, each list being associated to a distinct cell. The method is adapted to process variable length cells divided into subcells each containing a header (SCH) to distinguish a first/last subcell (FSC/LSC) of a cell from other subcells (ISC, LSC).

Abstract: An electro-optic device incorporating a waveguide includes a locating electrode formed on a plate for locating an electrical phenomenon in a waveguide carried by the plate. The electrode comprises two juxtaposed flat surfaces, namely a locating surface relatively close to the waveguide and which has a relatively high electrical resistivity and a connection surface relatively far from the waveguide and which has a relatively low electrical resistivity. This juxtaposition makes it possible to eliminate at least partially deformation and/or attenuation of the guided waves. Applications of the invention include the implementation of a polarization modulator.

Abstract: A switching element with a plurality of operating modes, in particular for switching asynchronous time-division multiplexed packets, comprises inputs, outputs, a selective retransmission device for retransmitting a packet received on one input to one or more outputs on the basis of routing data associated with the packet, and a retransmission control device determining the mode of operation of the retransmission device. The retransmission control device comprises a direct routing device adapted to receive from the label of a packet received on one input a destination indication and to decode it into an output identifier corresponding to one output at least in order to retransmit the packet to an output designated by the identifier.

Abstract: Communication system and switching element used therein. To detect and remove partly established paths, a path release explorer packet is periodically transmitted from an outside node on established paths and each time it arrives in a node a check is made whether this node is a dead end for all directions. In the affirmative a path release packet is transmitted to a preceding node to possibly release the path to the dead end node. The switching element used in each node includes a first switching bus (TB, TM) to interconnect input ports (RX1/8) to output ports (TX1/8). One of these output ports (TX9) is connected to a second switching bus (SB) which has access to all input ports.

Abstract: A protection circuit for protecting circuit elements (TX) connected to line via terminal means (L1 and L2) from the effects of a transient abnormal high voltage surge, comprising a semiconductor switch (TR1 and TR2), a first circuit comprising a resistor (R1 ) in series with the conductor path of the semiconductor switch and a voltage reference means (D1, and D2)in parallel with the resistor and a junction of the semiconductor, and a second circuit comprising the first voltage reference means in series with a second voltage reference means (D3), the second circuit being connected in parallel with the resistor. The second circuit further includes a voltage dependent resistance (VC1). When the current through the resistor exceeds normal line current the voltage reference means (D1, D2, D3) clamp the voltage drop across the resistor and turn off the semiconductor switch.

Abstract: The invention relates to high voltage surge arrestors which are installed in parallel with an electric apparatus to be protected from excessive high voltages, such as a high voltage power cable or a transformer. The arrestor consists of one or more annular bodies (9,19,32), through the hollow of which a high voltage conductor (3,31) is terminated. The arrestor may also be used with penetrators and transformer bushings.

Abstract: A method of adjusting the pulse rate of a local clock (1) by generating a first pulse train at a first predetermined rate, dividing the pulse train by a divisor (3) to produce a second pulse train. The value of the divisor (3) is selected (4,5,6) so that the rate of the second pulse train is adjusted within a predetermined range.

Abstract: In practice, switching is a continuously changing mixture of point-to-point connections, point-to-multipoint connections with low fanout, and point-to-multipoint connections with high fanout. The switching elements of a switch optimized for point-to-point connections are additionally enabled to copy a few input signals for an arbitrary number of outputs, so that a very large number of copies is attainable for few input signals. This switch is supplemented by a copy switch which serves exclusively to make limited numbers of copies for a large number of input signals, which are then switched in the (group) switch as point-to-point connections. Point-to-point connections are operated as connectionless connections, but outside the switch act as virtual connections. Point-to-multipoint connections are operated as virtual connections (connection-oriented) by means of connection tables.

Abstract: There is no problem to excite the fundamental mode in a single-mode optical waveguide, if a laser is used whose operating wavelength is above the cutoff wavelength of the guide. However, these lasers are presently very expensive.Especially for the use in the subscriber area, where the relatively short transmission lengths allow to accept a certain amount of attenuation, it is proposed to use an inexpensive laser (6) whose operating wavelength, however, lies below the cutoff wavelength of the coupled optical waveguide (10). The excitation of only the fundamental mode is, according to the invention, possible with such a laser (6). A single-piece metallic module housing (1) is provided in which the laser (6), being moved perpendicularly to the module housing axis (1), is aligned to it by adjusting screws (12). A magnifying optic (9) is provided. The magnification causes a decrease of the angle at which the laser light reaches the face of the optical waveguide (10).

Abstract: Landing aids using phased-array antennas must be very carefully calibrated. Conventional methods use probes which are inserted into each individual radiating element of the array antenna. For 6-bit phase shifters, this method is not suficiently accurate. A method and an apparatus are disclosed wherein the aperture illumination of the array antenna is determined from the output of an integral waveguide and compared with a desired aperture illumination. The difference between actual value and desired value is compensated for iteratively with the aid of an adaptive control system.

Abstract: A microwave antenna has a circularly symmetrical reflector made of a material having a liquid phase and a solid phase, with the reflector being obtained by centrifuging the material while in its liquid phase and then allowing it to pass into its solid phase. This results in a convex paraboloidal reflector face having a very high degree of surface accuracy. When housed inside a microwave absorbing ring connecting the reflector face to a microwave-transparent window and used with a suitable source held at a predetermined focus position between the reflector and the window by means of microwave absorbent triangular struts, the antenna demonstrates improved radio and mechanical properties. Alternately, the centrifugally cast convex paraboloidal reflector may be used as the main reflector in a hybrid Cassegrain optical system in which the subreflector has a "conformed" non-paraboloidal surface that is machined from a solid piece of material.

Abstract: The measurement equipment (SMC) is used in a telecommunication switching system to check if the cell rate of each of a plurality of individual cell streams multiplexed in a same link remains within the limits on the basis of which its multiplexing was allowed. To this end the equipment checks at the end of each measurement interval (MTI) and for a plurality of cell rates [(M-S)/A, (M-S/2)/A, . . .] if the expected probabilities to exceed these cell rates are exceeded or not. In the positive the cell rate is limited by dropping cells. Thus an expected complementary (with respect to 1) cumulative probability distribution function of the cell rate is approximated by a staircase-shaped function.

Abstract: An in-phase coupled strip linear CO.sub.2 waveguide laser includes an upper aluminum plate and an aluminum waveguide bed including parallel ridges, each in the range of about 2 to about 5 mm wide, at a gap of about 0.5 to 2 mm from the upper plate. The slots are about 2 mm deep to prevent discharge therein and about 1 mm wide. The width of the slots is selected to permit coupling between the discharge channels formed between each ridge and the upper plate while separating the discharge beams in each channel. Discharge in each channel is in-phase coupled in the fundamental mode to produce a single lobe far field with a simple Fabry-Perot resonator.

Abstract: Switches (multiplexers, demultiplexers, data switches) are provided for optical signal transmission, by which two or more data streams are combined or separated or by which combined data streams are switched. Instead of buffering as in time-division multiplexing, wavelength conversions are performed. By space-division and wavelength-division multiplexing, storage problems can be largely avoided.

Abstract: To be able to load an ATM switching network as efficiently as possible, the successive cells of one and the same connection are routed to the output by as many different paths as possible; however, mutual overtaking of successive cells must be avoided or corrected. Each cell is held at the output until it is certain that no older cell can be buffered in the switching network. Before the cell is passed on, a check is made to determine whether the cells received from the switching network later include an older cell which must be passed on before that cell. At the input end, consecutive numbers ("Sequence Numbers") are allocated to the cells. A buffer (1) at the output end is operated, at least in part (1 . . . d), in the manner of a shift register, thereby introducing a predetermined delay. Prior to the output of a cell, at least the shift-register-like portion of the buffer is examined as to whether a cell written in later is to be put out earlier: if so, the two cells are interchanged.

Abstract: The method is implemented on the site where the cable is to be installed on pylons, and consists in taking wire strands from individual reels to make up a bundle, and in clamping the bundle together to obtain the cable as and when the cable is required for installation purposes. The invention is applicable to transporting electrical power.