In some embodiments, {HEAD ~ the combination} may further include {TAIL ~ one or more error checking codes} 
In some embodiments , { HEAD ~ the combination } may further include { TAIL ~ one or more error checking codes }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL