Abstract: An automatic exchange of a telephone system comprises a PCM switching network with a plurality of cascaded stages for establishing temporal and spatial connections between incoming channels on input lines of the first stage and outgoing channels on output lines of the last stage in response to commands from external controllers dialoguing with internal controllers of the network. Pairs of switching matrices forming part of nonadjacent stages are combined into modular switching units each provided with its own internal controller. Routing instructions are transmitted from an external controller to a first internal controller which selects a signal path through the matrices of its own switching unit and informs a second internal controller of that selection whereupon the latter extends the path through an adjoining switching unit, and so on until the connection is completed.

Abstract: A five-stage PCM switching network of an automatic telephone exchange is divided into a set of outer modular units each including a first-stage and a fifth-stage matrix, a set of inner modular units each including a second-stage and a fourth-stage matrix, and a set of central modular units each including a pair of third-stage matrices. Each modular unit is provided with an individual base-level microprocessor controlling the switching of its matrices and the checking of their performance with the aid of ancillary equipment including transceivers sending back outgoing signals and samplers delivering bytes from corresponding time slots at opposite ends of an established signal path to a comparator in the associated microprocessor.

Abstract: A mass memory for use with telecommunication equipment comprises a plurality of memory units associated with respective controllers. Each memory unit includes a command module, dialoguing with the associated controller, and a multiplicity of memory modules for the storage of respective information and redundancy bits of a number of data words, one bit of each word being written in an integrated charge-transfer circuit individually assigned thereto and being continuously recirculated when the memory unit is idle. The command module contains a corrective logic which includes a generator of redundancy bits and intervenes during reading and writing phases.

Abstract: A stored-program control system for a telephone exchange or the like comprises processing units coupled to several main memories and to several mass memories. Each mass memory includes one or more memory modules each with one or more rows of shift registers of the charge-coupled type, operating in a serial-parallel-serial mode, and a control module equipped with a self-correcting logic and a microprogrammed time base.

Abstract: For the selective energization of combinations of up to m data outputs of a data concentrator with n data inputs (n > m), the concentrator is provided with n control inputs energizable in various patterns. The concentrator comprises a logic network with an enabling section and a performing section, each in the form of a truncated orthogonal matrix with m rows and n columns of gating circuits. In each matrix the number of gating circuits decreases from n in the first row to (n-m+1) in the last row.

Abstract: Message transmission between subscriber stations served by different central offices takes place via frequency-division channels through the intermediary of couplers recognizing different line signals, specifically pulse sequences modulating the amplitude of a fixed-frequency oscillation on a test wire, to initiate certain switching operations. A processor, responding to these signals either upon initiation of a connection or in the course thereof, summons an available modem which is temporarily connected to the associated coupler and emits a characteristic a-c signal picked up by a remote coupler at another exchange which thereupon causes its processor to connect another modem to it, to the exclusion of any subscriber line to which that coupler may have been previously connected.

Abstract: A call monitor for a telephone exchange, including a processor intervening in the establishment of a connection between associated line links with the aid of a switching network, comprises a first memory storing information about each line link and a second memory containing codes that identify all possible states of a connection of interest to the processor along with all intervening conditions termed evolutions. During a time slot allocated to a particular line link, a multibit comparator receives data from the first memory concerning a connection involving that line link, along with updating information from the line link itself, on one set of inputs and further receives, on another set of inputs, a succession of evolutionary codes read out from the second memory until a match is detected; the read-out is then terminated and an instruction, if required, is sent to the processor and/or to the switching network.

Abstract: Switching criteria are transmitted over a plurality of trunk lines to a central office of a telecommunication system in the form of a set of binary signals modulated on three carriers for each trunk line, the triads of carriers being cyclically sampled and demodulated. During each sampling interval t.sub.i allocated to a particular trunk G.sub.i within a cycle, a locally generated identification code of that trunk is transmitted to each of three sections of a read-only memory MS, each memory section permanently storing four different threshold values for the length of "on" signals (1) and "off" signals (0). Integrators IN, rejecting spurious changeovers from one type of signal to the other, feed respective counters CT via respective coincidence circuits CFR which receive from a register MG the bits of the preceding cycle and reset arithmetic units .sigma.