Abstract: To enable a data packet to be broadcast from one input (I1) to a plurality of outputs (01, 02, 03, 06) the switching network comprises in each switching plane at least one stage (S2) comprising switches (SE4, SE5, SE6) adapted at least: to route multiple copies of a packet that has been multiplied on its upstream side (SE1), and to multiply a packet by forwarding it several times in succession to the same output; the copies thus created being routed subsequently by the switches (SE7, SE8, SE9) of a downstream stage (S3). The switching network has application to photonic ATM switching centers.

Abstract: This subscriber access unit includes an electronic subscriber line interface circuit (1) whose functions include: cell header translation, routing label addition and bit rate control (policing). It further includes concentrators (2) including electronic statistical time-division multiplexing devices (34.1, . . . , 34.16) and electronic periodic time-division demultiplexing devices (47.1, . . . , 47.16) and a photonic wavelength-division multiplexing and bit rate changing device (38), a photonic periodic time-division multiplexing without wavelength-division multiplexing device (40), a photonic bit rate conversion and wavelength-division demultiplexing device (43) and a photonic periodic time-division demultiplexing and wavelength-division multiplexing device (41). This structure optimizes use of photonic technology and electronic technology to achieve a minimal implementation cost.

Abstract: An optical wavelength converter has an optical signal input adapted to receive an optical signal whose wavelength is to be converted, an optical signal output adapted to emit an optical signal whose wavelength is the required wavelength, after conversion, and at least one control electrode for applying at least one electrical signal to control the wavelength of the output optical signal. The converter is controlled by a method which comprises a calibration phase for establishing a law linking at least one of said control electrical signals to said required output wavelength and storing said law in a storage device, and an operative phase for addressing said storage device using the required output wavelength and numerical-analog conversion of the data from the storage device addressed in this way for application to said control electrode(s).

Abstract: A photonic concentrator is used to connect to a telecommunication network subscriber terminals sending and receiving data in the form of fixed length cells using asynchronous time-division multiplexing, in particular on an optical fiber. The concentrator comprises, for processing cells from a subscriber terminal, a time-division and non-synchronous statistical spectral multiplexing stage, a synchronization to a local clock stage, a spectral multiplexing and bit rate converter stage, and a periodic time-division multiplexing stage. To process cells addressed to subscriber terminals it comprises a periodic time-division demultiplexing, spectral multiplexing and bit rate adjuster stage, a bit rate converter stage and a spectral demultiplexing stage. The concentrator has applications in telecommunication networks.

Abstract: A multiplexer and a demultiplexer time-division multiplex and demultiplex binary data in the form of cells having a fixed number of bits. For example, to time-division multiplex cells comprising 424 bits the original bit rate of a block of 16 bits of a cell is multiplied by four, each cell being divided into a series of 27 blocks. The blocks constituting each cell are concatenated after their bit rate has been multiplied. Similarly, the demultiplexer divides the bit rate by dividing each cell into blocks, separating consecutive blocks by a gap and dividing the bit rate successively in each block. The multiplexer and demultiplexer have applications in time-division multiplex telecommunication networks.

Abstract: A photonic switching matrix comprises a plurality of wavelength converters at respective inputs of the matrix to assign a wavelength to each cell applied to an input of the matrix. An optical buffer common to all the outputs of the matrix stores each cell for a duration selectable between 0 and k.T.sub.c where k is an integer and T.sub.c is the duration of cell. A space routing stage comprises a filter for each output of the matrix passing to a given output only cells having a given wavelength. The converters and the buffer are controlled according to routing information indicating for each cell the output of the matrix to which said cell is addressed and for selecting the duration for which each cell is stored in the buffer so as to construct a queue for each output to avoid conflicts between two cells to be switched to the same output presented at the same time as the input of the switching matrix. The switching matrix has applications in telecommunication networks.

Abstract: The asynchronous time division multiservice satellite center can be used for connecting analog subscribers, digital subscribers, and asynchronous time division digital subscribers. It comprises multiservice concentrators that may be local (CBLA, CBLN, CBLNA, CBLOA), distant (CBEA, CBEN, CBENA, CBEOA), versatile local (CBLM), and versatile distant (CBEM), and a synchronous to asynchronous and asynchronous-to-synchronous converter (CAS), together with a multiservice control unit (UCB) including a multiservice switching network (RCB) and a control station (CS). The multiservice switching network is connected to the multiservice concentrators and to a parent exchange via multiplex links conveying cells, and it provides cell switching. The concentrators connected to analog subscribers or to digital subscribers cellulize and decellulize information therefor.

Abstract: The present invention consists in a system for exchanging encoded messages between stations, in which each station comprises a connection module (2) connected to a signal bus (LMS) and to a data bus (LMI), the signal and data buses being serial multiplex links synchronized by a general timebase, a time interval comprising consecutive even-numbered and odd-numbered time slots being allocated in each signalling frame to each connection module. In this system for exchanging encoded messages, the signal and data buses are duplicated for security reasons, signalling messages being sent simultaneously on both signal buses and data messages being sent simultaneously on both data buses, messages being received on one bus only.

Abstract: In an existing time division exchange system the known switching network and connection units are retained, but the control of these units is taken over by a pair of new control units which replace a collection of previous units such as multi-registers, markers, translators, call charging devices etc. The new control units each comprise a multi-register portion and a dialogue portion with the multi-register portion governing the setting up and the clearing down of traffic while the dialogue portion performs most of the communication between the multi-register portion and the rest of the exchange equipment. The control units are microprogrammed machines under the control of a "macroprogram" assembled using the conventional computer techniques. The control units are connected to a data processing center via a monitoring unit.

Abstract: Connection unit for linking subscribers to an exchange in a time switching system comprising at least a space-time concentrator consisting essentially of a subscribers' connection circuit, a concentration network, a set of supply and supervising circuits for a subscribers' junctor set, multiplex time transmission digital terminal sets, and a logic control unit which controls the space-time concentrator, the said logic control unit operating on a basis of time sharing between the various switches.