How does the alternating possession arrow work?

The scorer operates the arrow (Art. 12.6 and 49.1).

• Setting it first: the team that does not gain the first control of a live ball after the opening jump ball gets the first alternating possession. Point the arrow towards that team's opponents' basket (the basket it is attacking).
• Jump ball situations: in every jump ball situation after the opening tip, the team the arrow favours gets a throw-in from the nearest place, not directly behind the backboard. Examples are a held ball, the ball going out when the referees are unsure or disagree who touched it last, and a live ball lodging between the ring and the backboard (except between free throws).
• Reverse it as soon as the alternating possession throw-in ends.
• Start of quarters: the team entitled to the next alternating possession starts the 2nd, 3rd and 4th quarters and each overtime with a throw-in from the centre line extended, opposite the scorer's table.
• Half-time: reverse the arrow immediately after the end of the first half, because the teams swap baskets.
• Violation on the throw-in: if the team violates during its own alternating possession throw-in, it loses that possession. Reverse the arrow straight away, and the ball goes to the opponents for a throw-in from the same place.
• Fouls: a foul by either team before a quarter (other than the 1st) or overtime starts, or during the alternating possession throw-in, does not cost the team its possession. The arrow stays where it is.