Siemens Aktiengesellschaft

Klaus Eberlein

Werner Nagler

Lothar Schmidt

Gerhard Schaich

Josef Birlmeier

Fritz Hlawa

A circuit arrangement for telecommunication switching systems, including PCM time division multiplex telephone switching systems, with double central switching matrix by which two corresponding line trunk groups comprising a sub-switching matrix each and a group control unit each, are allocated to each other in pairs via two time-division-multiplex lines. The line units and the PCM-lines leading to the central switching matrix, which are individually respectively allocated to the two line trunk groups, and which are connected with the respective sub-switching matrix of their own line trunk group during normal service, are switchable, during emergency service of one of the two line trunk groups, to the sub-switching matrix of the respective other line trunk group. In order that no calls already interconnected via the line units of the affected line trunk group up to the time of the switch-over are interrupted, each local control unit transmits all call data of interconnected calls to its associated control unit while still in normal service, on which basis the appertaining calls are securely interconnected within the sub-switching matrix of the associated line trunk group.

Circuit arrangement for telecommunication switching systems,

A telecommunication exchange system has a plurality of switch facilities over which signals are emitted on an average only during a part of their respective occupation. A signal current source for emission of the signals is provided having a call-handling capability limited by signal current load. A signalling system is provided for serving a distribution of the load and provides pulse sequences having respectively identical pulse spacings. Pulses of different pulse sequences simultaneously transmitted over different switch facilities have chronologically different phase relations and a chronological offset from switch facility to switch facility. The offset is such that the pulses of the different pulse sequences connect chronologically to one another with respect to pulse termination and pulse beginning. The switch facilities are allocated for receiving the pulse sequences from the signalling system to a respective one of the pulse sequences of a specific phase relation. The allocation is executable upon consideration of allocations already existing and affecting signalling events. No more than a given number of switch facilities is allocated with respect to the pulse sequences having a respective specific phase relationship. This given number is determined by the signalling current loadability of the current source. With a given allocation of this given number of switch facilities to each of the plurality of phase relations, one or more additional switch facilities request an allocation to a phase relation for signalling, they either receive a signal to abort a setup of the calls or are only allocated a respective phase relation after a given limited delay time if the switch facilities allocated to the phase relation have become fewer than said given number, or if all allocations remain filled at the end of the given delay time, receive the signal to abort setup of the call.

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Wolfratschausen, Germany

Klaus Eberlein