Circuit arrangement for centrally controlled time division multiplex telecommunication switching systems, particularly PCM-telephone switching systems with line trunk groups connected to a switching matrix

A circuit arrangement for centrally controlled telecommunication switching systems, including PCM-telephone switching systems wherein a central switching matrix serving for interconnection together with a program controlled central processor serving, at least, for its control and the required switch identifier processing for alternate circuit switching (stand-by service) is provided in duplicate, and wherein a number of local trunk line group, each group with a sub-switching matrix for the connection of external trunk and/or subscriber lines and equipped with a local programmable control unit for the reception of switch identifiers from said lines, for switch identifier pre-processing as well as for forwarding switch identifiers to the central processor and the transmission of switch identifiers over these lines is provided and wherein in each of said line trunk groups, the respective sub-switching matrix is, separately by group, internally connected via groups of link lines with switching matrix interfaces to the one and the other of the parallel central switching matrices and wherein data connections respectively, per local control unit are brought into service condition and/or thereby maintained therein, for data exchange between the local control units on the one hand and the respective service-ready and/or service prepared processor on the other serving the foregoing switch identifier processing and wherein the line trunk groups are allocated to each other in pairs, and wherein line units including ones from the group comprising subscriber line circuits, multiple subscriber line circuits, trunk line termination circuits, multiple trunk line termination circuits, primarily connected to their sub-switching matrix and within the respective line trunk group serving for the external connection of subscriber and/or trunk lines, are switchable in a manner in which the line units of respectively a first of these two line trunk groups are additionally switched to the sub-switching matrix of the respective other, of a respective second line trunk group, whereupon the corresponding switch identifier processing as well as the sub-switching matrix setting for the connections to be interconnected via the switched-over line units is likewise executed by the local control unit of the other second line trunk group wherein the improvement comprises that through the switch-over within each of said pairs of line trunk groups allocated to each other for implementing the stand-by service, one of the two central processors along with its allocated central switching matrix is prepared by the other of the two central processors, likewise with its central switching matrix and during continuing service of the first, by way:

• first, of data connections which are brought into service-ready state by the other central processor via its allocated central switching matrix to the local control units of all first line trunk groups;
• second, of connection data which indicate, via the central switching matrix still in service and via the sub-switching matrix of the respective individual connections within the second line trunk circuit which external sub-switching matrix is connected with which of its like or which two external sub-switching matricies are connected with their line and which are stored in the local control units of the respective second line trunk groups and which on the basis of a request signal from the local control unit of the respective first line trunk group to the respective second line trunk group, are transmitted per line trunk group pair, via local transmission paths of the line trunk pairs respectively from the last named control unit to the first named control unit and stored therein, and which in addition are retrieved therefrom through the other central processor;
• third, of connections, which said last-named central processor establishes in conjunction with the retrieved connection data via its central switching matrix and the sub-switching matrices of the respective first line trunk groups;
• and
• that the switch-over of all line trunk groups from the sub-switching matrices of all first line trunk groups to those of all second line trunk groups occurs independently of the execution of the latter procedure for the establishment of connections.

A circuit arrangement for centrally controlled telecommunication switching systems, particularly PCM-telephone switching systems wherein a central switching matrix serving for interconnection together with a program controlled central processor serving, at least, for its control and the required switch identifier processing for alternate circuit switching (stand-by service) is provided in duplicate, and wherein a number of local trunk line group, each with a sub-switching matrix for the connection of external trunk and/or subscriber lines and equipped with a local programmable control unit for the reception of switch identifiers from said lines, for switch identifier pre-processing as well as for forwarding switch identifiers to the central processor and the transmission of switch identifiers over said lines is provided and wherein in each of said line trunk groups, the respective sub-switching matrix is separately internally connected by groups via groups of link lines with switching matrix interfaces to the one and the other of two parallel central switching matrices and wherein data connections respectively, per local control unit are brought into service condition and/or maintained therein thereby, for data exchange between the local control units on the one hand and the respective service-ready and/or service prepared processor on the other serving the foregoing switch identifer processing and wherein the line trunk groups are allocated to each other in pairs, and wherein line units primarily connected to their sub-switching matrix and wherein the respective line trunk group serving for the external connection of subscriber and/or trunk lines, are switchable in a manner wherein the line units of respectively a first of these two line trunk groups are additionally switched to the sub-switching matrix of the respective other of a respective second line trunk group, whereupon the corresponding switch identifier processing as well as the sub-switching matrix setting for the connections to be interconnected via the switched-over line units is likewise executed by the local control unit of the other line trunk group, wherein the improvement comprises that through the switch-over within each of said pairs of line trunk groups allocated to each other for implementing the stand-by service, one of the two central processors along with its allocated central switching matrix is prepared by the other of the central processors, likewise with its central switching matrix and during continuing service of the first, by way:

• first, of data connection which are brought into service-ready state by the other central processor via its allocated central switching matrix to the local control units of all first line trunk groups;
• second, of connection data which indicate, via the central switching matrix still in service and via the sub-switching matrix of the respective individual connections within the second line trunk circuit which external sub-switching matrix is connected with which or its like or which two external sub-switching matrices are connected with their like and which are stored in the local control units of the respective second line trunk groups and which on the basis of a request signal from the local control unit of the respective first line trunk group to the respective second line trunk group, are transmitted per line trunk group pair, via local transmission paths of the line trunk pairs respectively from the last named control unit to the first named control unit and stored therein, and which are retrieved therefrom through the other central processor;
• third, of connections, which said last-named central processor establishes in conjunction with the retrieved connection data via its central switching matrix and the sub-switching matrices off the respective first line trunk groups;
• and
• that the switch-over of all line trunk groups from the sub-switching matrices of all first line trunk groups to those of all second line trunk groups occurs independently of the execution of the latter procedure for the establishment of connections.