The new system links camera feeds from the 30 ballparks to the operations center. M.L.B. has also installed its own stationary high home plate cameras at each stadium to offer its video officials the best possible view of base runners who might have to be repositioned depending on their decisions.

A manager must leave the dugout and tell the umpire he is challenging a call. He cannot yell his request from the dugout. He cannot throw a flag or sunflower seeds. He can also argue a play but must answer if an umpire asks, “Are you making a challenge or not, buddy?”

Each manager gets one challenge a game, but if he is correct, he gets another. He must specify to the umpire exactly what he is challenging and can ask that more than one element of a play be reviewed.

There are long lists of what can or cannot be challenged. Force plays, tag plays, ground-rule doubles, hit by pitches and fan interference are on the roster of challengeable situations.

But balks, foul tips, balls and strikes, and the so-called neighborhood play at second base during a double-play attempt are on an even lengthier list of plays that cannot be challenged.

During the testing of the system in spring training — which involved broadcast trucks outside each ballpark, not the Manhattan operations center — 61 plays had been reviewed and 11 had been overturned, through Tuesday. Forty-nine of the reviews came from managers’ challenges; the other 12 were initiated by the umpires’ crew chief (which can happen only from the seventh inning on).

Baseball officials expect that force plays and tag plays will be the largest segment of challenges.

Joe Torre, the former Yankees manager who is now M.L.B.’s executive vice president for baseball operations, said the system was intended to preserve the “instinctive” desire of managers to dispute a call while providing a remedy to reverse incorrect calls that in the past could not be.