Abstract: A bit-by-bit time-division digital switching network switches incoming and outgoing isochronous digital channels having rates which are different but sub-multiples of a given low rate. After phasing the incoming channels, bits having a predetermined binary state are detected. Previously stored addressed words of the outgoing channels to be switched to the incoming channels are read out and multiplexed into an intermediate multiplex highway in response incoming channel bits having the predetermined state. This predetermined state is respectively that of the received bit, or its inverse if the sum of the incoming channel word bits is respectively less than, or greater than half the number of incoming word bits. Each multiplex highway multiframe is composed of a number of outgoing channel address words equal at most to half the number of incoming channels.