Radio communication system

A communication system comprising:

• a network comprising a plurality of first access points, each access point being configured for bi-directional communication, using a first radio protocol, with a communication device that has been associated with the access point by an association data exchange, wherein each access point is further configured to receive, at a first data rate using the first radio protocol, a multicast radio message from a wireless communication unit that is not associated with the access point and to forward the multicast message onto the network;
• a first radio transmitter configured to send data comprising a control message, addressed to one or more specific wireless communication units, at a second data rate, using a second radio protocol different from the first radio protocol;
• and
• a wireless communication unit comprising a further radio transmitter configured to transmit a multicast radio message at the first data rate using the first radio protocol, and further comprising a radio receiver configured to receive and decode a control message from said first radio transmitter received at the second data rate using the second radio protocol, and being configured to execute a function in response to receiving the control message.