Time-divison multiplex switching network with spatial switching stages

Claim 1

A switching network for interconnecting time-division multiplex (TDM) lines which transmit pulse code modulated (PCM) signals having a plurality of individual PCM words, said switching network having a plurality of time and spatial switching circuits associated with different groups of said TDM lines, wherein the individual PCM words are transmitted in parallel form from incoming TDM lines to outgoing TDM lines through said time and spatial switching circuits, said switching network comprising: intermediate storage means in each of said spatial switching circuits, said intermediate storage means having a plurality of individual storage positions, each of which is individually assigned to a predetermined destination route in said switching network; writing means connected to said intermediate storage means for writing individual PCM words into said storage positions pursuant to addresses corresponding to the destination routes to be followed by each PCM word, said writing means writing each PCM word into said storage positions during a time interval individually allocated to the origin route of the PCM word, the time interval forming part of the time slot of the time channel associated with that PCM word; reading means connected to said intermediate storage means for cyclically reading the PCM words from said storage positions in the next time slot; said switching network including a plurality of said spatial switching circuits in a first stage and a plurality of said spatial switching circuits in at least a second stage following said first stage and demultiplexer-multiplexer means for connecting the outputs of said spatial switching circuits of said first stage to the inputs of said spatial switching circuits of said second stage to distribute PCM signals, which are interleaved in time at said outputs of said first stage according to destination routes, among said inputs of said second stage corresponding to the destination routes.