A counter counts a first time duration commencing from the last transition to inspiration and whereby if the first time duration elapses before a transition to expiration is detected, {HEAD ~ the controller} initiates {TAIL ~ the supply} of a given expiratory pressure 
initiates
A counter counts a first time duration commencing from the last transition to inspiration and whereby if the first time duration elapses before a transition to expiration is detected , { HEAD ~ the controller } initiates { TAIL ~ the supply } of a given expiratory pressure
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH