Patent EP-0134009-B1 (EP)
IPC: H04Q3/54
Filed: 1984-08-06
Granted: 1987-09-02
Abstract: 1. A circuit arrangement for telecommunications systems, in particular telephone exchange systems, which contain central and/or sub-central, information processing (sequential) switching circuits (ZW, GP ...GPn), in which a switching circuit (ZW) is supplied with switching characteristics which emanate from different source switching devices and are to be processed in the switching circuit and which form self-contained series, each of which includes, as first switching characteristic an initial switching characteristic which initiates a series, and successive switching characteristics which follow at regular intervals of time, and overall forms an item of information, and in which the switching characteristics arrive successively, mixed in their time sequence in respect of different series, and indicate the respective series to which they are assigned by a source of address attached to each switching characteristic, and in which the switching characteristics are supplied to the switching circuits via FiFo-stores (FiFo), and in which the quantity of initial characteristics continuously supplied to a switching circuit (ZW) is determined, and in which, by means of a counting result to this effect and a comparison of said counting result with a threshold value, where necessary the supply of switching characteristics is restricted in that as a result of the rejection of an initial switching characteristic the successive switching characteristics, assigned to said initial switching characteristic in a series, are also prevented from being supplied to the respective switching circuit (ZW), characterised in that a common FiFo-store (FiFo) is provided for initial switching characteristics and successive switching characteristics, and that a counter (Za) is provided which, of the switching characteristics supplied to the FiFo-store (FiFo), selects the initial switching characteristics in order to restrict the counting process to the initial switching characteristics only and which either carries out this counting in consecutive counting time intervals, at the end of each counting time interval is reset to its starting position, and supplies a counting result which is to be compared with a threshold value at the end of a counting time interval, or else is continuously reset in stepped fashion and always keeps available a counting result which is subjected to a comparison procedure which is continuous, but is performed at least once during each forwards counting procedure and/or each reset procedure with the assistance of a threshold value, that when the threshold value is exceeded the supply of initial switching characteristics to the FiFo-store (FiFo) is restricted, as a result of which all the successive switching characteristics assigned to an initial switching characteristic are also prevented from being accepted, that whenever the number of counted initial switching characteristics exceeds a threshold value, a load counter (W) produces a reduction signal (-v) which is supplied to a restriction device, is transferred from the restriction device to the central switching circuit (ZW) and from there to the decentral switching circuit (GP), and that in the decentral switching circuits (GP) the received reduction signals bring about a rejection of subscribers and thus a restriction of the occurring initial- and sucessive switching characteristics.