Responsive to the condition signal, the control part controls {TAIL ~ the announcing arrangement} at {HEAD ~ the particular time instant} 
Responsive to the condition signal , the control part controls { TAIL ~ the announcing arrangement } at { HEAD ~ the particular time instant }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD