In a two-stage switching network wherein each primary (A) switch has access to each secondary switch over an individual link, the failure of any one link seriously affects accessibility as between incoming and outgoing paths of the network. The present proposal is applicable where said paths are t.d.m. highways as in the digital switching subsystem (D.S.S.), and enables three requirements to be met (1) serial re-routing to avoid effect of an internal faulty link (2) avoidance of normal traffic b...

The telephone switching system comprises a plurality of speech path units, a juncture switch unit for interconnecting the speech path units, a central processing unit for controlling the speech path units and the junctor switch unit. Each speech path unit comprises a time switch which shifts a signal which is time-division-multiplexed from time slots of a plurality of incoming highways to other time slots on a plurality of outgoing highways, a digital trunk circuit for processing a register sign...

In a PCM switching network, a signal routing device is disclosed for diverting signals from a faulty section of the network to an emergency section. All the transmission paths included between the emergency section and the faulty section are shifted by one step towards the emergency section. At the outputs the reverse shift is performed.

A method and apparatus for automatically correcting errors in the cyclic routing memory of a four-wire TDM telecommunication exchange. The address data in the cyclic routing memory for the control of each of the two switching paths for one four-wire connection through the exchange are each stored in a separate column of the cyclic routing memory. The address data includes parity bits for the input buffer storage device, and parity and busy bits for the switching matrix and group switch devices. ...

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 ...

A digital switching system for smooth transfer between active and standby mode of duplicated transmission controllers at a host office (host digital trunk interface controllers) and duplicated transmission controllers at a remote office (remote local controllers).

A switching exchange in which data on each incoming line are applied to an encoder which produces redundant code words therefrom. The switching matrix is divided into n sub-switching matrices which each transmit a different sub-code word. The outputs of the sub-switching matrices are connected to a decoder which corrects erroneous data words and in addition indicates the occurrence of a fault. Each sub-switching matrix may have its own setting processor receiving identical setting information fr...

Time-slot interchange circuitry for use in a time-division switching system is disclosed having n+1 input interface units and n+1 output interface units to serve n PCM lines. One of each group of n+1 interface units is designated a spare unit and control circuitry is disclosed for autonomously channeling incoming data words or outgoing data words through a spare unit and for autonomously altering the control for the spare unit in the event of failure of a unit in service.

A time-division multiplex switching network is constructed of units designed as time stages which operate blocking-free and which are multiply divided. A plurality of units of identical structure to a plurality of switching units of a switching network portion is assigned to each switching network portion, the plurality of units being operated as multiplexers at which the outgoing time-division multiplex lines are connected and whose normally non-utilized outputs can be connected by way of switc...

A transmission system in which a plurality of data streams are to be multiplexed and sent between receiving and transmitting equipment. At the transmit end the system comprises a plurality of worker tributary cards (51, 52) each having an input port (57) connected to an individual tributary to be sent to an associated multiplexer, and a stand-by tributary card (56) operative to replace a failed worker card. All the worker tributary cards (51-55) are interconnected by a common line (60) leading t...