In the receive direction, {HEAD ~ the interface} receives a 155.52 Mbps serial data stream, removes the ATM cells from the STS 3c framing, and verifies {TAIL ~ the HEC code} 
verifies
In the receive direction , { HEAD ~ the interface } receives a 155.52 Mbps serial data stream , removes the ATM cells from the STS 3c framing , and verifies { TAIL ~ the HEC code }
OTH OTH OTH OTH OTH 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 REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL