In some embodiments the tag backscatters a combination of {TAIL ~ its tag response} and {HEAD ~ one or more other codes} 
In some embodiments the tag backscatters a combination of { TAIL ~ its tag response } and { HEAD ~ one or more other codes }
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD