Patent EP-0177735-B1 (EP)
IPC: H04Q11/04
Filed: 1985-08-28
Granted: 1989-08-02
Abstract: 1. Circuit arrangement for telecommunication installations, especially for telephone exchanges, with centralized and/or decentralized information-processing devices with a limited performance in terms of information-processing capacity, and with a central switching matrix (K) and with decentralized termination groups (LTG1, LTGn), to which in each case a decentralized device (GP1, GPn) is assigned, and to which connection-specific lines, e.g. subscriber lines (T), local junction lines (V) and longdistance junction lines (F), are connected, and which exchange data, for example dialling information and control and setting information, with the central device (Z) in order to process the individual switching operations and with measuring devices (Mg, Mz) for determining the respective acute information-processing workload in a central device as well as in each of the decentralized devices and for detecting information-processing traffic overloading and for averting such overloading by means of rejection devices (A) assigned individually to the decentralized termination groups, by means of which rejection devices the volume of information-processing requests occurring is reduced, in that a stipulated proportion of these requests is rejected, and with transmission switching means for signalling data about the deviation of the acute information-processing workload with respect to the capacity of a central device and about corresponding information-processing traffic overloading to the decentralized devices, characterized in that there are provided in a decentralized device at leat two rejection devices (A1, A2, A12), of which one effects rejections according to the information-processing traffic overloading determined in the decentralized device and the other effects rejections according to the information-processing traffic overloading occurring or imminent in the central device, and in that, in a decentralized device, a counter (Z) with a lower and an upper threshold value and an intermediate starting position is switched forward by each rejection and switched backward by each acceptance of an information-processing request, in that this counter not only outputs a blocking signal when the upper threshold value is reached and an unblocking signal when the lower threshold value is reached to a choke device (D), but is also reset to its starting position when either of the two threshold values is reached, and in that the choke device of a decentralized device blocks the seizable incoming junction lines connected to the respective termination group in several proportion levels with respect to incoming seizures, in that it is switched over in each case into the next-higher blocking proportion level when a blocking signal is received or into the next lower blocking proportion level when an un blocking signal is received, and in that by means of the choke device the seizable incoming junction lines which are to be blocked according to the blocking proportion level reached in each case are marked in each case at their other ends as blocked for outgoing seizure, in that either switching signals for a backward blocking are transmitted individually per respective junction line or blocking data are transmitted jointly per line group which mark the junction lines to be blocked in each case at the other line end for outgoing seizures or specify the proportion of junction lines to be blocked in each case at the other line end for outgoing seizures.