Phone calls between the dugout and bullpen will be made using cellphones this season as part of T-Mobile becoming the official wireless partner of Major League Baseball.

"Everyone wanted to make this deal happen," said Tim Brosnan, MLB's executive vice president of business. "It just took a while to get here."

T-Mobile built the new On-Field Communication System, which is encrypted and won't be compromised by the in-stadium wireless used by fans. The communication system uses geofencing, meaning the network won't operate if the phones are taken into seats or the clubhouse.

"Technology had to be at the forefront of this deal," said Mike Belcher, T-Mobile's vice president of branded communication and experience marketing. "We're coming into a sport that is rich in tradition, and we have to use technology to better the game both on and off the field."

The phone system will use T-Mobile's 4G network and a Samsung Galaxy 3, a standard phone that is available to consumers. However, the dugout phones will remain in place in case teams prefer to use them.

T-Mobile officials say they will make the multiyear partnership work through branding in dugouts and by making the stadium experience better for fans. The company promises to make wireless connectivity better in stadiums through cooperation with Major League Baseball Advanced Media, the digital arm of the league.

"We want to help fans who follow the No. 1 digitally consumed sport," Belcher said. "We want to enhance the experience, whether it's allowing them to see special highlights or to order food or merchandise from their seat."

The deal is done with MLB, but teams will get the choice to opt in, depending on whether they have a competing carrier. The deal does not give exclusive wireless highlights rights to T-Mobile, as the league sells that to fans through its MLB At-Bat App, which has been the highest-grossing sports app on the iPhone and the iPad for four straight years.

There has been some brush-back over the years when the idea of replacing the landline has been brought up, but a high-profile recent snafu at least got the general public thinking it was time for a change.

In Game 5 of the 2011 World Series, the St. Louis Cardinals bullpen coach Derek Lilliquist misunderstood what manager Tony LaRussa was saying. Lilliquist warmed up the wrong pitchers, sending in reliever Lance Lynn instead of closer Jason Motte.

Telephones have been used for dugout-to-bullpen communications since at least 1930, according to baseball historian Peter Morris. The move from a hard line to wireless in the dugout mimics the move away from public telephone booths.

Federal data indicates there were about 2.1 million pay phones across the country in 1999. Today, that number is about 425,000.

MLB's partnership with T-Mobile was unveiled Tuesday at the International Consumer Electronics Show (CES) with appearances by American League MVP Miguel Cabrera, National League Rookie of the Year Bryce Harper, MLB president of baseball operations and former Yankees manager Joe Torre and former Chicago White Sox slugger Frank Thomas.

T-Mobile's deal with MLB means the end to their NBA investment, which included a partnership with the league and broadcaster Charles Barkley and Miami Heat guard Dwyane Wade.

The company is the fourth-largest wireless carrier in the United States.