Well, this is actually a general question. Sometimes we need to communicate with the coaches & the players though there's no such title or term on the rule book & mechanics. I once read the FIBA - Referee & Players' Relationship, that tells me a ref should always be neutral & kind, but his "game call" & "game voice" should be absolute. The most impressive thing is that it says "the game is not a rules clinic, so if it's necessary to explain a call, do that as brief as possible."
So, I'd like to learn from you guys how to be a sensible ref who can communicate with the coaches & players. And I hope you could give me some examples, thanks.