setter or hitter call the set/play

Question
I was just wondering what is more common, having the setter call out who they are setting to, or having the hitters yell out their position (or whatever has been predetermined) to let the setter know they are available and then just all be ready for what the setter decides. Also, who should call the predetermined plays, the setter or possibly the coach relaying it to the team?

Answer
Kimimi-
 There's a reason you'll see setters flashing signs prior to the serve...and that's so they don't have to call anything out once the offense begins to form.  The key is not allowing the defense to tune into what you're doing, hence the signs.  The setter shouldn't be calling sets out loud, ecspecially on the first play.  Now, in transition, you'll often times see hitters call a suprise shoot or quick, but typically even in transition each player has a "basic" ball that is set to them should there be no other call.
As for your second quesiton, your coach is going to determine that.  However, most coaches will want some part in the offensive calling.  a lot of times you'll see the coach with the clip board flashing sings to the setter...which are then relayed to the team.  Sometimes the coach will call one set that he would like to see the setter play, but ultimately the setter will decide if he/she feels that particular set weill work against the defense they are showing.  At the end of the day, a lot of coaches will put there trust in the setter to ultimately run the offense. Just remember, the setter of any team is the quarterback...not the hitters.  They are the ones who call the shots.  

I hope this helps.  If you have any other quesitons...please feel free!

Matt