The present invention relates to a communication system and in particular but not exclusively to a communication system for use in {HEAD ~ a push} to talk over {TAIL ~ cellular network} 
The present invention relates to a communication system and in particular but not exclusively to a communication system for use in { HEAD ~ a push } to talk over { TAIL ~ cellular network }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL