NFHS 2-2-1 NOTE
A state association may permit game or replay officials to use a replay monitor during state championship series contests to determine if a try for goal at the expiration of time in the fourth quarter or any overtime period (0:00 on the game clock) should be counted, and if so, determine if it is a two- or a three-point goal.
NFHS 1-14
A red light behind each backboard or an LED light on each backboard is permitted to signal that time has expired for a quarter or extra period. In facilities without a red light behind or an LED light on each backboard, the audible timer's signal shall indicate that time has expired.
NFHS 5-6-2
Each quarter or extra period ends when the signal illuminates or sounds indicating time has expired, as in 1-14.