Thus, to give a simple example, at the start of an alternation the slave MCU 802 sends the RTP packets received from a base station such as 804 with the M bit at the logic value 0, leaving the M bit at the logic value 0 for the RTP packets transmitted to the master MCU, while the M bit is set to the logic value 1 for the RTP packets retransmitted to the various base stations 804 to 806 participati