NFL communication before the snap
Saw this tonight on Reddit and thought you chimps might enjoy it. This guy explains what happens before the ball is snapped in the NFL in terms of the communication and play calling.
Typically:
1 - The offensive coordinator calls the plays (some head coaches serve as their own OC's). If the OC is in the booth, he relays it down to the sideline because the radio communication to the QB is only allowed from the sideline. Usually the QB coach is the relay man. If the OC is down on the field, he speaks to the QB directly.
2 - Everyone wearing a headset talks and listens to each other. The HC is listening and comments (and calling plays if he serves as his own OC.) The other guys are chiming in with whatever they observe and are offering suggestions. Some guy in the booth is tasked with saying to the HC whether or not to challenge a play. All of this is open line (I believe) - so it's a perpetual conference call.
3a - Huddle talk. A play is called, and often some codes to switch to different plays. Also, the QB will say if (using Peyton Manning as an example) "Omaha!" means something or not. For example, the QB can say we'll run play X unless I say "eagle" in which case we'll run play Y. Omaha means the snap count is changed to two instead of one - beware of the hard count.
3b - LOS talk - the Center is calling out the blocking scheme. The QB is deciding, based on what he sees whether or not to go to Eagle, and whether or not Omaha will be invoked. The QB may signal a man to go in motion so he can see how the defense responds (if someone runs with him, it's man, if not, it's zone). If he has called "Eagle" then the teams knows to run the play designated Eagle. But the QB could call out "Raptor" which means nothing - he's just making sure that the defense can't figure out the code words, or he's seeing if the defense will change alignment. Even if he has called "eagle" he can then kill it and go back to the original play (usually "Kill! Kill! Kill!"). He can then go to his hard count, which is an attempt to draw the D offsides, but's it's also a chance to see how LB's and DB's move.
Going through a scenario:
QB calls Play X, Eagle Y, Omaha 4 (X and Y are usually very jargon-y, so we'll skip that for now) in the huddle.
They come to the line. the Center informs the rest of the line, that the D is lined up in a base 3-4, which due to study sessions previously in the week, means the line will use Blocking scheme A for X or blocking scheme B for Y. Or the center could use a code word to switch up the blocking scheme if it wasn't covered in the study session. Furthermore adjusts can be made by identifying the "Mike" - the primary MLB. Hence "54 is the Mike! 54 is the Mike!"
Meanwhile the QB decides whether the original play X or the Eagle play Y (and note, they could be other code words that mean specific plays - if the QB says "Hawk" every knows that Hawk is play Z). Let's say he wants to stick with play X, but he wants to know more about the defense. He calls his WR to go in motion, but then return to his original spot. The defender runs with the motion man. So it's likely man coverage, at least for that guy. Play X really only works against zone coverage, so he changes: "Eagle! Eagle! Eagle!" The QB pauses and see if the defense changes - they don't, so he calls Omaha which means we're going on the 4th hut. "Omaha! Omaha! HUUUUTTTTT!"
No one jumps offside on defense, but two LB's show blitz. the QB decides they we're fooled by the count. So now he knows that it's man coverage with a two man blitz. Furthermore, he might notice that the identity of "Mike" has changed. So instead of continuing the count, he calls (and points) "51 is the Mike! 51 is the Mike!"
The defense now has to decide if knowing that the offense knows it's a blitz will be too risky, in which case, they can start calling codes, too. They will have codes to switch to a different blitz, change back to base defense, or possibly anything. The d-signal caller now starts yelling (well, continues, as he, like the QB has been calling signals since he saw the O come to the line).
Now the QB has to decide if the D has switched out of the scheme he thinks they're in, or if it was a bluff, and they're still gonna do it. So, he starts the count again. "Omaha! Omaha!" - turns the count back to 4.
HUTT-HUTT!!!!
Now the defense may jump again, and the QB will think he's got them in the man coverage, two LB blitz for real, and so he continues his count.
HUTT-HUTT!!!!
That's four HUTs so the ball is snapped, and the play has begun.
4 Pointing
Covered earlier, but the QB often corrects the C's call of Mike (or in some cases has sole authority to decide on who the Mike is). Or if he thinks, based on what he thinks he knows, that, say the SS is on a blitz, he'll point it out, so his back will know who to look for on the blitz pickup (or the OL will change protection schemes to pick up the blitz themselves.
5 Defense signals.
Imagine the whole process in reverse, without access to the snap count. the D signal called gets a call from the sideline (either relayed to him from the sideline, or called by the DC or HC from the sideline). They'll have one defense called, another to switch to on a code word. They will also have other code words to change to specific other schemes and of course Kill! as well.
As the offense does it's things, the defensive signal caller tries to glean what he can about the play they've called. If the O-line is in three point stances, they may favor the run (or they may be pretending to run and then pass). If they are in a two point stance (standing up, it's the opposite. The offense alignment may tell the defense what types of plays it can run from that set, so the d-signal caller can remind his teammates either through codes or or through just yelling "watch for the draw!" (for example) directly. Then if the QB is switching things around or pretending to, the d-signal caller can switch things up or pretend to.
6 The Booth
If the OC or DC is up there, he is communicating to the sideline the plays he wants. He is also communicating with his subordinate coaches and the HC other things that may be of value. If he's not up there, someone else will be, relaying his observations from the booth. They also have phone lines to speak to players directly on the sideline. There is another guy who, among his other responsibilities, will be to monitor the stadium replays and (I think) the telecast to see whether or not to challenge a play (or even directly because he has a better view). Someone else will be logging a bunch of things (plays called, penalties, observations about the opponents, play results, etc for analysis the following week.
The shocking thing about all of this is they either 25 or 40 seconds to accomplish all of this shit. It's sort of ridiculous - it's like high speed poker and then high speed violence all at once.
