The instruments 44 are coupled to {HEAD ~ the control unit} 16 by {TAIL ~ a cable} 46 
by
The instruments 44 are coupled to { HEAD ~ the control unit } 16 by { TAIL ~ a cable } 46
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH