{HEAD ~ The common format} includes at least the transmission data length, the transmission data, the data frame number and the repeat request frame number, and is added with {TAIL ~ the error detection code} for all the data 
is added with
{ HEAD ~ The common format } includes at least the transmission data length , the transmission data , the data frame number and the repeat request frame number , and is added with { TAIL ~ the error detection code } for all the data
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH