Abstract: The present application concerns a multiplexing device (12,14) for a redundant channel bus (13). It comprises two arrays (12,14) of cascaded crosspoint cells, connected to opposite ends of the bus (13). The crosspoint cells of the first (12) of said arrays have means for establishing n data paths from n input data lines to n channels of n+x channels, and the crosspoint cells of the second array (14) have means to establish n corresponding data paths from the n channels to n output data lines. Further, the crosspoint cells comprise means to identically alter data paths in both arrays, said means being controlled by the means to recognize a faulty channel. The multiplexer is designed with a minimum number of gates, thus, providing a fast device for circumventing faulty channels. It is useful for fast and secure data transmission, especially suitable as a backbone bus device between independent central processing units.