Twenty years ago American football coaches would communicate the plays they wanted executed by sending it in with a player substitute. After that they tried using hand signals. For several years now they simply speak via communications technology directly with their key players.
Basketball coaches have no need for any communications technology. They stand directly on the side of the court within speaking distance from the action. Baseball managers continue to use hand signals.
The American military places extraordinarily high value on the development and usage of any and all technology which shorten, improves, quickens the communication between commanders and commanded. Combat helmets are outfitted with cameras and radio communication allowing for direct, one-to-one communication with each and every soldier.
It is said that the President of the United States can speak at any time, from any location, with any armed forces pilot in the sky. The 2012 raid on Osama bin Laden‘s compound was watched by the president and his national security team from the White House situation room.
