{TAIL ~ SBACK1 and SBACK2 signals} 480, 485 are asserted by the central arbitrator circuit of the system bus 110 over {HEAD ~ the bus} 110 
{ TAIL ~ SBACK1 and SBACK2 signals } 480 , 485 are asserted by the central arbitrator circuit of the system bus 110 over { HEAD ~ the bus } 110
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH