Abstract: A multiplex system having a main transmission channel (MC) for transmitting or not, within a pass-band corresponding to the information rate, information signals coming from a plurality of sub-channels in accordance with the priority levels of the sub-channels. A priority level having overflow authorization is assigned to certain of the sub-channels, an overflow transmission channel (OC) being provided for transmission by sub-channels having overflow authorization when the main channel (MC) is saturated.

Abstract: The arrangement multiplexes channels of differing bit rates onto a multiplex line. Channels are split according to a table assembled in a channel splitter. The table has a plurality of lines numbered by an index j. Each line j contains j .DELTA..sub.i, j .DELTA.S, and j .DELTA.X, where .DELTA..sub.i =di/dMAX, .DELTA.S=dS/dMAX, and .DELTA.X=dX/dMAX, i is an index numbering the multiplex channel, di is the bit rate of the channel i, dS is the rate of the service data, dMAX is the fastest of the di and dS, ##EQU1## and dTDM is the bit rate of the multiplex line. The table is assembled until each quantity on the line j exceeds VS, where VS=1+.epsilon.. Access to the multiplex line is given to the channel for the values of i where j.multidot..DELTA..sub.i >kVS+.epsilon., where k is an integer which is incremented each time access is given to the multiplex line and .epsilon. is a fixed value preferably equal to zero.