Circuit arrangement for centrally controlled telecommunications exchanges

A circuit arrangement for centrally controlled telecommunications exchanges, including PCM-TDM exchanges wherein are provided, in duplicate, a central switching matrix used for through-connection and a program-controlled central processor for standby operation which serves at least to control said matrix and to process the switching signals that are required for this purpose, and wherein a plurality of local line trunk groups are each equipped with a submatrix for the external connection of trunk and/or subscriber lines and with a local programmable control device to receive said switching signals from said lines, to preprocess said switching signals and transmit them to said program-controlled central processor and to transmit switching signals over these lines, and wherein, the respective submatrix in each of said line trunk groups, is connected internally group by group, separately over two groups of link circuits to switching matrix lines belonging, on the one hand, to a first, and on the other hand, to a second of the two switching matrices that are provided in parallel, and wherein, for a data exchange between the local programmable control device on the one hand and an operational or pre-operational part of the program-controlled processor, as the case may be, on the other, which serves for the switching signal operations and for the transmission of program and switching software, data connections for each local programmable control device are brought by the processor into operational condition to the local programmable control devices over one of the link circuits and through the switching matrix assigned thereto or retained therein, and wherein concentrators equipped with concentrator processors are connected, in their higher ranking switching center, to the submatrices of at least two line trunk groups, in order to perform their connecting process through one or the other of the line trunk groups, characterized in that

• two categories of line trunk groups are formed;
• each concentrator is connected to a line trunk group in the first category and line trunk group in the second category;
• to load the local programmable control devices with program information and/or line data and, when necessary, to load each of said concentrator processors with connecting data in a similar manner,
• firstly, the two individual connections for each line trunk group to the two switching matrices are reduced to one connection, such that the line trunk groups in the first category remain connected to the first two switching matrix and the line trunk groups in the second category to the second switching matrix, and the local programmable control devices associated with the line trunk groups in the first and second categories remain connected, through the data, to a first processor corresponding to the first switching matrix and a second processor corresponding to the second switching matrix, respectively;
• secondly, further connecting procedures continue to be carried out with the aid of the line trunk groups belonging to the first category, whose local programmable control devices are connected to the first processor, which processor is still conducting the operation at the time;
• and
• thirdly, the second processor performs the loading procedures with the local programmable control devices of the line trunk groups belonging to another (for example, the second) category and that, after the loading is completed, firstly, the local programmable control devices that have been loaded by the process are made accessible to the concentrator processors by the second processor, for the transmission of connecting data for new connections, and, secondly, connecting procedures for new connections are performed thereafter by the second processor.