Abstract: The invention relates to a method of setting up a call between a central module (33) and a remote module (37) of the type comprising at least one first transmission channel and one second transmission channel according to distinct primary and secondary bit rates respectively. According to the invention, the method comprises the steps setting up a call by default on the first channel; listening and searching for a signal indicating a secondary bit-rate requirement, assuming a detection of the signal indicating a secondary bit-rate requirement, a phase for the switching of a bit rate from the first primary bit-rate transmission channel to the secondary bit-rate transmission channel, associated with a step for the masking, during a predetermined masking period, of an acknowledgement signal sent during the default setting-up phase. The invention also concerns a corresponding switching method, transmission network section and transmission network.

Abstract: A method (10) is provided of setting up a call over a multiple bit-rate transmission channel between a central module (25) and a remote module (22). The channel comprises at least one first transmission channel (401) having a primary bit rate and at least one second transmission channel (402) having a secondary bit rate. Each of said first and second transmission channels is a two-way channel comprising a first transmission half-channel (43, 45) in one direction and a second transmission half-channel (44, 48) in another direction. The method comprises the following steps: setting up a call on the primary transmission channel, scanning for a signal indicating a secondary bit-rate requirement, and if a signal indicating a secondary bit rate requirement is detected, bit-rate switching from said first transmission channel (401) to the second transmission channel (402).