{TAIL ~ An input/output port} allows encrypted/unencrypted data to be input to/output from {HEAD ~ the BCU} 
{ TAIL ~ An input / output port } allows encrypted / unencrypted data to be input to / output from { HEAD ~ the BCU }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD