Abstract: Communications with timeliness guarantees, also known as real-time communications are established in a shared medium with different contention based technologies. A real-time station is able to transmit a noise sequence before the intended data packet transmission. The noise sequence being is to occupy the communication medium during a period of time preferably larger than the maximum transmission time of any contention based technology that can have access to the medium, hereinafter designated alien. As such, even if an alien station is transmitting, it will finish its packet during the transmission of the noise sequence. The method prevents the alien stations from accessing the medium as these stations will sense the medium busy after the end of their packet transmissions. This method can be used to support master-multislave real-time communications on shared media in which contention based technologies operate.