The message “CAL” appears in {HEAD ~ the display} 26, prompting {TAIL ~ the user} to calibrate 
prompting
The message “ CAL ” appears in { HEAD ~ the display } 26 , prompting { TAIL ~ the user } to calibrate
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH