Abstract: A signal distribution signal for a time-division exchange has a distributed control architecture. Its switching network is organized as a plurality of independent planes (RXA to RXD) with terminal units (UT) and control units (UC) are connected via multiplex links (MX) and are synchronized by a time base (BDG) via clock signal distribution modules (MD). Each terminal or control unit is connected both to the switching network and to the clock signal distribution means by at least two independent parallel connections (F1, F2) each of which comprises multiplex links (MX) connected to different planes of the switching network, and at least one distribution link (D) connected to a different distribution module (MD) for each of said parallel connections connected to a given unit. Such exchanges are used for telecommunications purposes.

Abstract: A connector comprises a socket and a plug. The socket is located on the edge of a printed circuit card and comprises two contact tabs at different distances from the edge. A housing is placed near the tabs to receive the plug and to hold two electrically interconnected spring contact blades in contact with the tabs. If the plug is inserted one way up into the socket, its blades are connected to respective ones of the tabs, therby establishing a connection. Alternatively, if the plug is inserted the other way up, the tabs of the socket are interconnected by the first spring contact blade of the plug, thereby establishing parallel connection.

Abstract: A terminal for electrically connecting electrical conductors (6) to rigid electrical terminal pins (7) comprises a plurality of U-shaped individual contacts (2). One arm (20) of each contact (2) is connected to one of the conductors (6). The other arm (23) is flat and is adapted to connect to one of the pins (7). The terminal further comprises identical contact supports (1, 1') having an internal groove (10) with a rounded bottom. It has internal compartments (12) along the lateral walls of this groove (10) and external compartments along the lateral walls of each contact support (1, 1'). The internal compartments (12) accommodate the flat contact arms (23) and the respective pins (7). The external compartments accommodate the contact arms (20) adapted to contact the conductors (6). An insulating member (3) maintains the contact supports (1, 1') in alignment.

Abstract: The presence of such signals is detected each time the following detection condition is satisfied, namely: that, for the duration of a predetermined "prior activity" period the amplitude of the signal on the telephone channel exceeds a threshold level while successive maximum values taken at short time intervals remain fairly constant in level. Apparatus for performing the method comprises a threshold level comparator (10) and a difference comparator (11) which control a detector (50) followed by a holdover circuit (60). The invention is particularly applicable to inhibiting echo suppressor circuits during telephone signalling or data transfer by telephone line.

Abstract: The box comprises a shallow bowl (1) which is hermetically sealed to a bell-shaped cover (2). Repeaters are housed in individual casings (4) which are fitted into a mother board (3) extending over the greater part of the bowl. Connector tabs (20) are provided through the mother board, with pressure contact points for making electrical contact with the individual repeater casings, and self-stripping prongs for making electrical contact with the insulated wires of a cable (8). This arrangement leads to very few connections being made in the path between a cable conductor and a repeater, and enables the box to be wired to a cable on site and without soldering.

Abstract: A cock for low-pressure bleeding of a gas from a gaseous mixture, said cock having a body (1) with an inlet (12) and a pumping outlet (13) for the mixture and a bleed outlet orifice (15), and a valve (2) which co-operates with the valve body and is situated between said orifice and the inlet, wherein the valve includes a semi-permeable membrane with a first surface (6A) which communicates with said inlet and a second surface (6) which communicates with said bleed orifice, the valve assuming a first position in which it allows the mixture to pass directly from the inlet towards the bleed orifice when the pressure of the mixture is lower than a given pressure, and a second position in which it closes the bleed orifice when the pressure of the mixture is higher than said given pressure, the gas to be bled off then passing through said permeable membrane.

Abstract: Subscribers (Ab1 to Ab8) in a telecommunications system are normally connected via respective subscriber lines (L1 to L8) to respective subscriber terminals (T1 to T8). Automatic subscriber line test means are connected via a subscriber line test bus (BL) and various relay contacts (r1 to r8 and re1 to re8) to the subscriber lines for testing purposes. Eight subscriber terminals (T1 to T8) populate a single circuit card, thereby constituting a terminal unit (TU1 to TUp). A group of terminal units is associated with a spare terminal unit (TUS). When a faulty terminal unit is detected, it is taken out of service and the spare terminal unit takes over. This is done by switching the subscriber lines connected to the faulty terminal unit over to the test bus. The spare terminal unit is likewise connected to the test bus. To enable the test means to continue testing the remainder of the telecommunications system without being interrupted by the emergency connection via the test bus, isolator means (I) are provided.

Abstract: The method relates to the detection of the training sequence of a self-adapting equalizer at the receiver end of a synchronous data-transmission system, the training sequence being preceded a synchronizing transmission of data transformed on coding into a succession of multivalent symbols such that the transmitted signal has a frequency spectrum which is substantially a single large-amplitude spectrum line. The training sequence begins with the transmission of data transformed on coding and at least one null symbol. The method consists in detecting the presence of the large-amplitude spectrum line in the signal formed by the received but not yet equalized symbols by means of a digital filter 40 and in thereafter detecting the first following major drop in absolute amplitude of the signal that lasts throughout the duration of one symbol period. This is done by means of a low amplitude level detector 50.

Abstract: An addressing circuit has a register search counter (20) connected to a first multiplexer (24) and to a second multiplexer (25), a memory (33) connected to the output of the first multiplexer for writing the type of processing of each register, a register counter (26) connected to the second multiplexer which is itself connected by its output to three address registers (28, 30, 32) in series. The output of the second register (30) is connected to the first multiplexer to write address the memory under the control of a write signal (CRW). The register search counter read addresses the memory and stops as soon as a register requiring rapid processing is detected; the second multiplexer receives a transfer signal (ST) to transmit the address applied to the output of the register search counter; the register counter (26) stops during the transfer signal.

Abstract: A multiple stylus print head, e.g. for printing a document in a facsimile system, has at least two parallel lines of styluses with the styluses being offset from one line to the next. Each line of styluses is built up from several tiers of interdigitated conductor pins (C) having tips that constitute the styluses per se. The tiers of pins are held together by respective strips of insulating material (7) forming comb-like structures which are then stacked together in such a manner that the combs fan out from the line of styluses. A plurality of groups (G.sub.1, G.sub.2) of stylus line forming comb structures are stacked together into a single stack.

Abstract: The power supply system comprises three levels: a primary level (PRI), a secondary level (SEC), and a tertiary level (TER). The secondary level is constituted by power supply circuits (S1 to Sn) which provide galvanic isolation between the primary and the tertiary levels, and which provide at least one intermediate voltage at a fixed level relative to a system reference potential (point R). The tertiary level comprises chopper power supplies (RD), converters (CV), and inverters (OND) connected to user equipment (UT).

Abstract: In a method of detecting the presence of speech in a telephone signal, a signal sequence is interpreted as constituting speech if its mean power level exceeds a threshold, the value of which is decreased as the number of passages through zero level in the sequence approaches 1.25 per millisecond (0.25 Hz). A speech detector implementing this method receives pulse code modulated signal samples on its input. It comprises a squaring circuit driving a digital accumulator whose output signal is proportional to the mean power level of each of consecutive 4 millisecond signal sequences. A change of sign detector and a second digital accumulator indicate the number of passages through zero level in each of these sequences. Banks of threshold comparators and a selector circuit are used to choose between the various threshold values. The selected value is lowest when the number of passages through zero level is between 5 and 6 per millisecond.

Abstract: The present invention relates to 1+1 type carrier telephone transmission systems for connecting two subscriber terminals to a telephone exchange via a common two-wire link, one of the terminals being connected via the conventional audio channel, and the other terminal being connected by a channel referred to as a super-audio channel. Disturbances caused in the super-audio channel by signalling, dialling and calling signals of the audio channel are reduced by inserting a current-limiting two-port network in series in the audio channel and at the exchange end of the 1+1 system, in between the filter which separates out the audio channel and the rest of the exchange. Advantageously, an interference limiting low-pass filter (50) is also placed in series on the audio circuit. It has a capacitive shunt arm with a mid point connected to exchange battery ground.

Abstract: The pump comprises a pump stator (5), an electric motor stator (4), and a rotor (6) that constitutes the rotor both of the pump and of the electric motor. The pump stator comprises a tubular non-magnetic lining to the electric motor stator, and the rotor is mounted excentrically inside said tubular lining and is equipped with radially movable vanes (63) that co-operate with said lining to provide pumping action when the rotor rotates. The arrangement is particularly applicable to oil-sealed vacuum pumps, and has the advantage of being more compact than units of similar performance, but equipped with a pump and a motor that are separate and interconnected by a mechanical coupling, as is conventional practice.

Abstract: A method and apparatus for accentuating the features of a monochrome image reproduced by means of a digital transcription.The apparatus includes an analog portion disposed between the digital-to-analog converter DAC (5) and an analog-to-digital converter (15) with analog sampling units (6,7), comparators (10,11,12), a subtractor (9) an amplifier (13) and a limiter to select and calculate the corrective term depending on the difference and on the digital processing means (17,18,19 and 20) to add the corrective terms to the numbers of the digital transcription.

Abstract: Image printing stylus bar, manufacturing method therefor and image printing device.The present invention relates to an image printing stylus bar with as many styli as there are image points on a scanned line on a document to be reproduced, a manufacturing method therefor and a printing device constituting an application thereof.The stylus comprises 2.m register stage chips (59, 60) each having a serial data input, n parallel outputs, a serial data output and control inputs, disposed on at least one film (57, 58) and connected in series in groups of m to constitute two shift registers, the parallel output of each of the m consecutive chips being connected to respective styli (51, 52) for marking image points with the same parity on each line.

Abstract: An apparatus for constituting a rotary magnetic brush comprises a hollow cylindrical member (11) with permanent magnetic strips arranged axially along its periphery. The strips have outwardly directed magnetic poles in a configuration in which north poles and south poles alternate circumferentially. A tube (13) made of non-magnetic substance surrounds said member without touching it. The tube is intended to have particles of magnetic powder deposited on its surface and the particles are made to rotate by rotating the member (4). This causes a rotating layer or "brush" of magnetic particles to be formed on said tube. Said member (11) and the tube (13) which surrounds it are longer than the "brush": An end portion projects beyond the "brush" and is housed in an electrical stator (14) which drives the member (11) by making use of the poles which form the brush. The invention applies to developing electrostatic latent images.

Abstract: A digital frequency sender comprises a generator which supplies multi-frequency codes by cyclically scanning a table under the control of a time base (BT). The sender comprises a logarithmic generator (GL) which delivers single-frequency signals, a logarithmic adder (AL) which sums two single-frequency signals in compressed form, and a frequency output unit (DF) controlled by a computer (CAL). The invention is particularly applicable to time division telecommunication exchange division.

Abstract: An alarm preprocessing logic system for use in a computer controlled digital switching exchange including a central computer, the alarm preprocessing logic system comprising defence modules each allotted to a respective portion of the exchange for detecting a plurality of types of alarm therein and including means for forwarding detected alarms via redundant alarm data transmission means (CAa, CAb, SLM1, SLM2, COL) to alarm processing logic including: means for confirming an alarm (PT2); means for attributing a category to received alarms depending on type of alarm and on the exchange unit which originated the alarm; and means for grouping alarms according to the category attributed thereto (PT1, MDI, MAP), and for classifying alarms in an order of priority; the alarm processing system further comprising data interchange logic connecting the alarm processing logic to the exchange central computer and arranged to ensure that alarms are sent to the central computer in their order of priority.

Abstract: A three-passage valve comprising (1) a body with a main passage (10) and two secondary passages (12,13), each of the secondary passages being fitted with a respective closure member (2,3) and the valve as a whole being provided with a single, common actuator unit (6) to operate the closure members in such a manner that the valve can occupy any one of three positions: a first position in which the main passage is in communication with a first one of the secondary passages while the other secondary passage is closed; a second, or intermediate, position in which both of the secondary passages are closed; and a third position in which said first passage is closed while the main passage is in communication with said other secondary passage.