The receipt and processing of {HEAD ~ the communication packet} may be acknowledged by the central controller to {TAIL ~ computer}  
The receipt and processing of { HEAD ~ the communication packet } may be acknowledged by the central controller to { TAIL ~ computer }
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH