1. A multirate time-division digital switching network comprising: first multiplexing means in which first-order digital data channels transmitting words having a first and a second formats which are different from, but multiples of, a given format and first rates which are different from, but multiples of, one another are given a first multiplexing converting them into second-order digital data channels having a second predetermined rate, said second format words being formed by a predetermined sequence of first format words; second multiplexing means in which said second-order digital channels are given a second multiplexing converting them into third-order digital data channels having a third predetermined rate: a digital switching unit having at least one buffer store in which the first format words of the first-order channels multiplexed into the third-order channels are grouped at a resultant address having first and second part, whose first part is the address of the second-order channel containing the first format word of the first-order channel in the third-order channel and whose second part is the address of the first-order channel in the second-order channel; means for inserting, in each of the first format words of a second-order channel, bits forming a pseudorandom sequence having a known period so that the bits of a given rank of the words of a third-order channel form a number of interleaved pseudorandom sequences; means for separating said pseudorandom sequences and for deriving therefrom the addresses of the first format words in the second-order channels; means for deriving from said addresses of the first format words the addresses of the first order channels; means for deriving from the addresses of the first format words additional addresses significative of the serial number of the first format word in the second format word forming sequence; and means for re-arranging the first format words in the second format word forming sequence according to their additional addresses.
1. A multirate time-division digital switching network comprising: first multiplexing means in which first-order digital data channels transmitting words having a first and a second formats which are different from, but multiples of, a given format and first rates which are different from, but multiples of, one another are given a first multiplexing converting them into second-order digital data channels having a second predetermined rate, said second format words being formed by a predetermined sequence of first format words; second multiplexing means in which said second-order digital channels are given a second multiplexing converting them into third-order digital data channels having a third predetermined rate: a digital switching unit having at least one buffer store in which the first format words of the first-order channels multiplexed into the third-order channels are grouped at a resultant address having first and second part, whose first part is the address of the second-order channel containing the first format word of the first-order channel in the third-order channel and whose second part is the address of the first-order channel in the second-order channel; means for inserting, in each of the first format words of a second-order channel, bits forming a pseudorandom sequence having a known period so that the bits of a given rank of the words of a third-order channel form a number of interleaved pseudorandom sequences; means for separating said pseudorandom sequences and for deriving therefrom the addresses of the first format words in the second-order channels; means for deriving from said addresses of the first format words the addresses of the first order channels; means for deriving from the addresses of the first format words additional addresses significative of the serial number of the first format word in the second format word forming sequence; and means for re-arranging the first format words in the second format word forming sequence according to their additional addresses. 2. A multirate time division switching network according to claim 1 in which the second-order channels each contain first-order channels of one and the same first rate, further comprising an address dividing circuit receiving the addresses of the words in the second order channels and supplying first order channel addresses equal to the remainder of the division of said word addresses by the number of first order channels of a given rate in a second-order channel.