Don Hanson checks for telephone dial tones on a mainframe Jan. 26, 2012, Eielson Air Force Base, Alaska. The mainframe hosts more than 4,000 telephone lines and provides Eielson's comm. capabilities. Hanson is an Altech voice systems network technician assigned to the 354th Communications Squadron. (U.S. Air Force photo/Staff Sgt. Christopher Boitz/Released)