Major League Baseball announced a partnership with T-Mobile on Tuesday that will allow phone calls between the dugout and bullpen during games this season to be made with cellphones.  T-Mobile, which is the fourth-largest wireless carrier in the United States, built the new communication system.  The program uses geofencing which won't allow the phones to operate if removed from the dugout or bullpen.  The system also won't be compromised by in-stadium wireless that is used by fans and other employees.  MLB says the regular landline phones will remain in place in case teams prefer to use them during the season.