NBA differences?

[Danvrapp]

I attended my first NBA game last night since becoming a basketball official and I noticed something that I thought was odd. During the first half, the teams were going towards their own basket, and vice versa in the second half. I know that in High School and below (college...?), you go towards your own basket in the second half. Anyone know why this is???

It was funny last night, but I spent more time watching the officials than the players. Very different mechanics