When Interference Occurs Before the Ball Is Snapped - The New York Times
Why NFL Coaches Rely on Bose Headsets to Strategize the Super Bowl | PCMag
Technology and the Game | NFL Football Operations
The QB School Show: Episode 28 - What do Quarterbacks Hear in Their Helmets? - YouTube
When technology fails: How NFL teams handle helmet speaker outages - Green Bay Packers Blog- ESPN
Gridiron Goes Wireless / New technology makes life easier for football coaches, players and fans
Do NFL quarterbacks wear headsets in their helmets? If so, what kind of information is conveyed through their headsets during a play? - Quora
Qubit - Football, ice hockey, baseball radio communication device in helmets. NFL, NHL, NCAA, high school, youth, semi pro
Aaron Rodgers covered his helmet's earholes to play in noisy Seattle | For The Win
Ferguson: A deep dive into communication between QB and coach - CFL.ca
Coach to Player
What Does The Green Sticker On Brady's Helmet Mean? (and much more about NFL coach to QB radios) - YouTube
How do the headsets in quarterback helmets work? - SBNation.com
SB Nation GIF on Twitter: "SHOCKING DISCOVERY OF NFL HELMET EARPIECE http://t.co/M1CIK3SWAn" / Twitter
Do Quarterbacks Have Headsets in Their Helmets? – Ear Rockers
Can you hear me now? NFL headsets going digital – Orange County Register
XFL helmet change will lead to faster games
Football helmet - Wikipedia
The evolution of NFL headsets - The Boston Globe
Coach to Player
Speakers in every player's helmet would eliminate need to huddle - ProFootballTalk
