Within the IS 54 standard, which describes the interface between mobile and base equipment for North American digital cellular systems, {HEAD ~ each information time slot} is preceded by {TAIL ~ a known sequence}, designated as the preamble 
is preceded by
Within the IS 54 standard , which describes the interface between mobile and base equipment for North American digital cellular systems , { HEAD ~ each information time slot } is preceded by { TAIL ~ a known sequence } , designated as the preamble
OTH 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 HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH