1. In combination: a plurality of data word sources; a switching network, comprising a plurality of input terminals and a plurality of output terminals, for completing communication paths therebetween; a plurality of buffer memories, each uniquely associated with one of said input terminals, for storing data words from said data word sources; means for generating control signals defining two data word sources which are to intercommunicate; and memory assignment means responsive to said control signals for storing data words from the two data word sources defined by said control signals in different ones of said buffer memories when data words from both of said data word sources would, in the absence of said control signals, be stored in the same one of said buffer memories.