Abstract: A TDMA cellular mobile radio system has at least one network control unit, at least one radio transceiver, and at least one multiplexor for multiplexing and demultiplexing digitally encoded and compressed speech data transmitted between the network control unit and radio transceiver. The bandwidth of the speech data is reduced through compression. The bandwidth of the speech data required on a radio transceiver side of the multiplexor is further reduced by buffering the speech data arriving at the multiplexor at a relatively high modulation rate, retransmitting the buffered speech data at a relatively lower modulation rate, buffering the speech data arriving from the multiplexor at a relatively lower modulation rate, and retransmitting the buffered speech data at a relatively higher modulation rate.