A system 16 wherein the network comprises {HEAD ~ a plurality} of {TAIL ~ receiving units} in communication with a server 
A system 16 wherein the network comprises { HEAD ~ a plurality } of { TAIL ~ receiving units } in communication with a server
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH