The control system may update {TAIL ~ the shadow ledger} directly or interrogate the remote communications unit for {HEAD ~ an update} after the remote ledger is updated 
The control system may update { TAIL ~ the shadow ledger } directly or interrogate the remote communications unit for { HEAD ~ an update } after the remote ledger is updated
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH