How does in-game offensive/defensive play-calling work?

[SupermanXx]

I've always wondered this and never really taken the time to analyze it

So.. I hear the QB has a speaker in his helmet that the coach can call the play through. Is this speaker shut off after the play is called by an NFL worker so that the coach can't yell "HE'S OPEN LOOK LEFT RUN RIGHT OH MY GOD!" during a play?

on defense, who calls the plays and how are they called? when the d-coord sees the opposing team bust out 4 wides, does the dime package get called into the defensive captain thru a headset speaker also? or what

nothin imperative, but a response from you guys would be much appreciated

thanks!

 

[Muhast]

yes it is shut off after a certain amount of time i believe. Whenever they break the huddle it shuts off. Otherwise qb's would have an extreme advantage over defenses.

Defense is usually called from the sideline i believe.

 

[AmericasTeam31]

Usually the defense is called from the sideline with hand signals to the defensive captain, most of the time it's the middle linebacker. Or if there are subs coming in they will relay the play through the subs.