Abstract: Binary message signals arriving over a PCM link at a retransmitting station, with a predetermined average bit cadence subject to random variations, are cyclically written in an 8-stage buffer register under the control of an 8-pulse writing counter stepped by clock pulses extracted from the incoming bit stream. The contents of the buffer register are read out under the control of an 8-pulse reading counter stepped by a local pulse generator whose pulse rate substantially corresponds to the predetermined cadence. Any deviations of the actual bit rate from the predetermined cadence are detected in a phase comparator receiving mutually interleaved monitoring pulses, once per 8-bit cycle, from the two counters.

Abstract: An electronic circuit breaker feeding a d-c/d-c converter from a power supply common to several such converters includes a normally saturated main or switching transistor T.sub.1 in series with the associated converter, the latter having an output from which auxiliary voltage is fed back to an ancillary transistor T.sub.2 lying in series with a voltage divider R.sub.1, R.sub.2 serving to bias the main transistor into conduction. A further transistor T.sub.3 triggers the cutoff of the main transistor T.sub.1 when the converter draws excess current, part of which flows through the voltage divider R.sub.1, R.sub.2. Another voltage divider R.sub.4 R.sub.5 in parallel with the first-mentioned divider biases the further transistor T.sub.3 and is thus traversed by a portion of the feedback current passing through the ancillary transistor T.sub.2, being therefore likewise cut off upon de-energization of the converter by the cessation of conduction through the main transistor.

Abstract: A terminal of a radio link or other two-way channel incapable of transmitting d-c signals, extending to a remote exchange, serves a multiplicity of local subscribers having keyboard-equipped telephone sets generating multifrequency selection signals accompanied by a d-c key signal. A detector at the terminal, responding to the arrival of a key signal from a calling subscriber line, connects that line to the outgoing channel to facilitate the transmission of the selection signals to the exchange; upon the arrival of an answer criterion from the exchange, the receiving branch of the channel is extended by another detector to the calling subscriber line.

Abstract: A main transmission line with inner and outer metallic layers on a dielectric tube is joined to a coaxial branch line via a pin and a sleeve forming extensions of the inner and outer conductors of that branch line, the pin penetrating two diametrically opposite bores of the dielectric tube while the sleeve is in contact with the outer metallic layer. Two lugs on the sleeve are soldered to that outer layer whereas a connection between the inner layer and the pin is established via a conductive coating of the wall of the remote bore which terminates in a metallic patch surrounding the outer end of that bore, the patch being insulated from the outer layer of the tube and being soldered to the projecting tip of the pin.

Abstract: A terminal serving a group of subscriber lines, some of which are invariably paired with remote stations through so-called "hot-line" connections, has a line concentrator/distributor from which a lesser number of line links extend to an automatic exchange at a nodal point of a data and/or voice telecommunication system. The line concentrator/distributor is controlled by a marker connected via a separate signaling channel with a line-control unit at the nodal point, that unit including a classifier which stores information fully identifying each associated subscriber line in terms of call number and class of service while also correlating the address of each line link on the terminal side with that on the address side.

Abstract: A multiple circuit interrupter, designed to facilitate the selective insertion of testers and other ancillary equipment into lines of a telecommunication system, comprises a body of generally rectangular outline which is receivable in a distribution frame and is split longitudinally into a central section and two lateral sections forming two rows of jacks between them. The jacks are arrayed in a plurality of groups accommodated in respective bosses of the split body projecting from a common base, each boss being engageable by a complementary socket containing a corresponding group of plugs. The bosses and the sockets are asymmetrically profiled to insure proper alignment of the jacks and the plugs.

Abstract: A network discriminating among switching signals appearing on a pair of talking wires of a telephone line comprises a light-emitting diode in series with each wire and a phototransistor illuminable thereby. The phototransistors energize respective amplifiers which work into a logic circuit distinguishing between current flow in one or both of these wires.

Abstract: A guide frame for the retention of printed-circuit carriers or other slidable articles comprises top and bottom members integrally molded from plastic material, each member including an elongate base with upstanding sidewalls and two sets of cantilevered ribs, the ribs of each set extending inwardly from a respective sidewall at an angle of substantially less than 90.degree. and terminating in a common longitudinally extending bar overhanging the base. The two bars are separated by a distance less than the thickness of a workpiece to be inserted therebetween, the herringbone pattern of the ribs facilitating such insertion from one end but impeding a withdrawal toward that end.

Abstract: A multiplicity of peripheral units are consecutively scanned, in respective phases of a recurrent operating cycle, by a central unit including a processor for incoming and outgoing data. The processor is connected to a programmer emitting a series of binary instructions during each phase, the instructions being stored in a read-only memory from which they are read out during respective subphases of each phase under the control of an address counter, the last instruction of a series carrying a characteristic bit which advances a phase counter and causes a switch of the central unit to a different peripheral unit.

Abstract: A system for the floating energization of a balanced load from a remote power supply via a pair of conductors, e.g., for feeding operating currents to repeaters of a telecommunication link, includes a circuit breaker controlled by an open-circuit sensor and an unbalance sensor through a memory unit provided with a pair of storage circuits. These circuits, designed to store a malfunction signal emitted by either of the two sensors until the arrival of a resetting signal, inhibit each other to prevent the registration of more than one malfunction at a time.

Abstract: A modular connector, to be assembled with other such connectors into a switching frame designed to interlink incoming and outgoing lines of a telecommunication system, comprises a flat prismatic housing of generally rectangular outline with a bank of input terminals and a bank of output terminals fitted into a pair of recesses on its opposite longitudinal edges. Leads extending from the two terminal banks within the housing are bent to emerge at a major housing surface overlain by a printed-circuit board whose conductor strips connect them with two further sets of leads emerging from the same major surface adjacent one of its transverse edges, the leads of these letter sets extending into a junction box attached to the housing along that transverse edge. Within the junction box, normally closed by a hinged door, contacts tied to the two sets of leads can be selectively interconnected or, if desired, extended to testing equipment.

Abstract: A coupling network at the junction of several multichannel TDM/PCM links comprises a pair of switching networks each including a set of input group units receiving incoming messages from respective PCM links, a set of output group units transmitting outgoing messages to respective PCM links, and a switching matrix interconnecting the two sets of group units. The bits of a code word representing an incoming message sample, arriving at a line unit individually associated with the respective PCM channel, are delivered to the corresponding input group unit during a receiving period, are read out during a transfer interval via the switching matrix to the output group unit for which they are intended, and are thence fed to the proper line unit during a transmitting period.

Abstract: A telephone exchange linked via PCM channels with subscribers engaged in a conference call includes switching circuits for transmitting to each participating subscriber, during an assigned time slot, the albegraic sum of the digitized voice-current samples from all the other participants. The digitized samples are logarithmically coded, each code consisting of a polarity bit, three range bits and four quantum bits; in order to facilitate correct addition or subtraction of the quantum bits of two codes to be summed (unless these codes signify the two lowest-ranking ranges), according to whether their sign bits are identical or different, the quantum bits of a lower-ranking code are shifted in a register toward less significant bit positions in which they would have their original numerical weight when prefaced by the range bits of the higher-ranking code.

Abstract: An electroacoustic transducer, such as a microphone or a telephone receiver, comprises a thermoplastic body with a central plateau surrounded by an annular recess from which an elastic ring projects slightly above the plateau to support a membrane in the form of sheet-metal foil carrying a piezoceramic layer. The body is overlain by a thermoplastic cover which has apertures for the passage of sound waves and is formed with an internal annular rib registering with the elastic ring to clamp the rim of the membrane therebetween. The body, the cover and a thermoplastic base are joined together by ultrasonic welding.

Abstract: Four bit streams arriving simultaneously over respective incoming lines at a transmitting terminal, connected via a PCM link with a remote receiving terminal, constitute recurrent lower-order frames whose bits are to be interleaved in a composite higher-order frame to be sent on to the remote terminal for redistribution over four outgoing lines. The bits of each incoming bit stream are cyclically written in an 8-stage buffer register at their rate of arrival, the contents of the register stages being read out at a higher rate to allow for the interpolation of ancillary bits constituting supervisory signals. Each higher-order frame consists of four subframes in which the message bits from the contributing bit streams are preceded by one or more ancillary bits; the latter include a discriminating bit in each of the last three subframes indicating whether or not a further bit in the fourth subframe is a stuffing bit or a message bit. The insertion of a stuffing bit, i.e.

Abstract: An incoming bit stream of a first bit frequency, divided into a succession of n-bit words, is converted into an outgoing bit stream of a second bit frequency with the aid of two n-stage buffer registers alternately loaded by two sets of interleaved writing pulses, on every n.sup.th cycle of the first bit frequency, with incoming words which are alternately read out on every n.sup.th cycle of the second bit frequency by two sets of interleaved reading pulses. A logic network detects the coincidence of a reading pulse from one set with either of two guard pulses immediately preceding and succeeding, respectively, each writing pulse of the corresponding set; upon such coincidence, a switching network transposes the two sets of writing pulses to restore an original relative pulse position in which the reading pulses of each set occur substantially midway between writing pulses of the same set.

Abstract: A storage network co-operating with a marker comprises a shift register whose stages are loaded in parallel with the digits of a call number received from a local subscriber, the first digit or digits of that call number being read out to an associated marker as an identification of a remote junction to which the call is to be extended via a transmission path selected under the control of that marker. When the marker has received enough digits to perform the switching operation linking the subscriber line with the selected transmission path, it activates a pulse generator which energizes an output lead in parallel with a counter whose reading is successively compared with the remaining digits still stored in some of the stages of the shift register. A comparator making this comparison, upon detecting a match between the pulse count and a stored digit, blocks the further readout of pulses to the output lead for an interdigit pause determined by a timer.

Abstract: A cable-TV system comprises a relay station linked by several HF cables with a distribution center feeding several subscriber stations via two-wire local lines, each HF cable carrying a respective TV program modulated on a common carrier. The distribution center comprises several switching matrices which are remote-controlled from respective subscriber stations for transmitting selected programs to any of them. Each subscriber station includes for this purpose a generator of a carrier frequency, above the band of incoming frequencies, which is pulse-modulated with the aid of a keyboard to identify the desired programs and is demodulated at a control unit tied to the associated switching matrix at the distribution center.

Abstract: A marker at a central-office terminal, controlling the establishment of connections between local subscriber lines and inter-office links via an associated line concentrator/distributor, includes a test-signal generator connected via a two-way coupler to an outgoing branch of an engaged link, a first signal receiver connected by the coupler to an incoming branch of that link, and a second signal receiver inserted in a normally balanced phantom circuit formed by incoming and outgoing branches of a local line communicating with the link. Upon the establishment of a connection including such a link between two subscriber lines served by respective central-office terminals, an alternating test signal generated at one terminal must be detected with a predetermined minimum threshold by the first receiver but not by the second receiver of the other terminal before message transmission over this connection can be initiated.

Abstract: A marker at a central-office terminal, controlling the establishment of connections between local subscriber lines and inter-office links via an associated line concentrator/distributor, includes a source of d-c test signals of reversible polarity connectable in a phantom circuit which extends from the central office via a transmitting and a receiving branch of a local line to a subscriber station tied to that line. The subscriber station has a master switch, establishing either an inactive position or a standby position, and a hook switch closable in the standby position to initiate or accept a call. Depending on the positions of these two switches, a current discriminator at the marker detects one of three current levels (zero, low or high) with either polarity of the test signal to determine whether a call can go through or whether an alarm condition exists.