After an unprecedented use of digital technology to call balls and strikes, the Vallejo Admirals are back to conventional umpiring.

But for two games, the local teams was part of an unusual test of PITCHf/x, a system that uses three cameras to track and digitally record baseball pitches. The company claims accuracy within an inch, and said its technology took more than seven years to develop.

The Pacific Association of Professional Baseball Clubs is the first league to use the system in back-to-back games as its exclusive way to call balls and strikes.

The Vallejo Admirals were part of that two-game piece of baseball history, though the scores — 7-3 in Tuesday’s game and 8-2 Wednesday night — favored San Rafael.

PITCHf/x has been installed in Major League Baseball’s 30 ballparks. It is used to track pitches at those games, recording them from the time the ball leaves a pitcher’s hand until it crosses home plate. MLB already uses the system in its Gameday webcast.

Speed, location and trajectory are recorded and can be broadcast in real time, whether for fans watching televised games or for performance analysis.

But for two San Rafael Pacifics games against the visiting Admirals, PITCHF/x called the balls and strikes, leaving other duties, such as calling runners safe or out, to its human umpire counterparts.

Twitter users quickly began calling it “RoboUmp.”

Besides the two Pacific League teams, Eric Byrnes also participated in the two-game experiment. In fact, he was a big reason the independent league ran the experiment.

Byrnes is a former Oakland A’s outfielder who also played for the Colorado Rockies, Baltimore Orioles, Arizona Diamondbacks and Seattle Mariners before exchanging his glove for a broadcasting career as an MLB Network analyst and KNBR radio host.

He also made appearances for the Pacifics last year, representing the Pat Tillman Foundation.

Byrnes used that connection to convince Pacifics front office officials to get the equipment installed in their ballpark. He also made donations to the Tillman Foundation for each walk and strikeout called during the two games.

He has emphasized that he isn’t trying to put any umpire out of work.

“If anything, we’re essentially going to add an umpire,” he said earlier this week.

Two umpires still worked the field as usual in the pair of games, and the home plate umpire remained on duty to call foul balls and determine whether runners made it home or were out.

Byrnes himself took the mike those two nights, providing fans with a voice for the strikes and balls called by the PITCHf/x system.

Several players said use of the technology appears to speed up the game, and Byrnes himself said the computer system “will change the game of baseball forever.”

It was just the latest example of the Pacifics League’s willingness to be cutting-edge. In its third year, the independent professional league also boasts of Sean Conroy, a Sonoma Stompers pitcher who may be the first professional ball player to announce openly during his career that he is gay.

The Admirals themselves had their first exhibition game with the Vallejo Police Department’s Police Officers Association, a game in which Police Chief Andrew Bidou threw out the first pitch.

Vallejo contended for the championship in 2014, but this year is a rebuilding season for the team, which has found itself in the basement of the four-team league with a 17-33 record, compared to the 32-16 record of Sonoma, 25-24 for the Pittsburg Diamonds and 24-25 for the Pacifics.

The Pacifics will play Vallejo again tonight, in a game starting at 7:07. The series continues at 5:05 p.m. Saturday and 1:05 p.m. Sunday.

Next week the Admirals travel to Sonoma for a six-game away stand, after which they return to Vallejo to play Pittsburg on Aug. 11-13.

The Vallejo Admirals play home games at Wilson Park, 199 Stewart St., Vallejo. Tickets are $5 general admission and $10 premium admission, and free to children 10 and younger.

Tickets are available at the park on game day, at the Admirals office, 444 Georgia St., Vallejo, and online at VallejoAdmirals.com.