the u.s. faa has installed three dme transponder types (not including those associated with a landing system): terminal transponders (often installed at an airport) typically provide service to a minimum height above ground of 12,000 feet and range of 25 nautical miles; low altitude transponders typically provide service to a minimum height of 18,000 feet and range of 40 nautical miles; and high altitude transponders, which typically provide service to a minimum height of 45,000 feet and range of 130 nautical miles. however, many have operational restrictions largely based on line-of-sight blockage, and actual performance may be different. the aeronautical information manual states, presumably referring to high altitude dme transponders: "reliable signals may be received at distances up to 199 nautical miles at line−of−sight altitude".