A1 attempts a pass to A2 during pressing action in A’s backcourt. The ball hits B’s backboard and deflects directly back to A1 who catches the ball and: (a) passes the ball to A2; or (b) starts a dribble.
The pass against B’s backboard was the start of a dribble which ended when A1 caught the ball. In (a), the pass is legal action. In (b), it is a violation for a second dribble.