{HEAD ~ The method} 21, further comprising detecting errors in the signals at {TAIL ~ a receiving terminal}, when no error is detected transmitting positive acknowledgment from a receiving terminal, and otherwise sending negative acknowledgments 
{ HEAD ~ The method } 21 , further comprising detecting errors in the signals at { TAIL ~ a receiving terminal } , when no error is detected transmitting positive acknowledgment from a receiving terminal , and otherwise sending negative acknowledgments
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH