Upon receiving a compel data command, {HEAD ~ a function block} of {TAIL ~ a device} publishes its output data on the bus 30 
of
Upon receiving a compel data command , { HEAD ~ a function block } of { TAIL ~ a device } publishes its output data on the bus 30
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH