Today, there are clocks all over our TV screens on Sunday. The TV graphics are hard wired into the stadium clock. The stadium clock is the official time. The side judge times the game on a watch, but that time on the watch only serves as a backup in case of a stadium clock malfunction or if the timekeeper makes an error; then the side judge can correct the scoreboard clock.
But, before 1970, the NFL stadium clock was the unofficial time and the officiating crew kept the “real” time on the field. The referee was the first official to keep time on the field. Then starting in the 1950s, the field judge kept the official time on the field, transitioning to the line judge when the position was added in 1965. (Since 2015, the side judge is responsible for monitoring the game clock, but this was long after the stadium clock was official time.)
The official keeping time would constantly update the teams (especially late in a tight game) of the time remaining.
When time expired, the official fired a starter’s pistol to signal the end of the quarter.
In the book So You Think You Know Football, Football Zebras editor Ben Austro explained how the fans were apprised of the time remaining:
Many times in that era, football was played in baseball parks, which had no need for clocks. For instance, Cleveland Municipal Stadium (home of the Rams and Browns) and Yankee Stadium (where the New York Giants played for 18 seasons) had modified analog clocks numbered 0–14. Tiger Stadium posted only the minutes remaining on the scoreboard for Detroit Lions home games.
When stadiums were equipped with clock displays, this timing was unofficial. This led to occasions where there was still time displayed on the stadium clock, but the officials declared the game over.
One rule remains today that had a different purpose in that era: the two-minute warning was just that — an official notification to both sidelines that the end of the half was coming up.
It seems completely foreign to fans today, but 50 years ago, that’s the way the NFL kept time, and teams and fans seemed to accept it.
Rival league had a different idea
When the American Football League came into existence, score board technology had advanced to the point where the AFL decided that the score board was the official time. That meant the timer up in the press box needed to stay on his toes and watch the officials for the stop the clock and wind the clock signals.
The entire AFL existence had official time on the scoreboard. In a concession by the NFL, each of the first four Super Bowls adopted the AFL rule that the official time was on the scoreboard.
When the NFL and AFL officially merged in 1970, the NFL adopted the AFL’s rule and official time went to the score board. NFL officials had to learn to look to the stadium scoreboard clock to check the time and not simply rely on the line judge and his starter’s pistol.
When the 2019 season draws to a close, the NFL will have turned the corner fully into the modern era: exactly half of its history would have the time kept on the field, and half would have the official time on display.