{HEAD ~ Interface} 710 generates a header error correction code, adds {TAIL ~ the HEC code} to the header, packs the ATM cells into the STS 3c frame, and sends the data out serially at the 155.52 Mbps data rate 
adds
{ HEAD ~ Interface } 710 generates a header error correction code , adds { TAIL ~ the HEC code } to the header , packs the ATM cells into the STS 3c frame , and sends the data out serially at the 155.52 Mbps data rate
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH REL 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 OTH OTH OTH OTH OTH OTH OTH