The Digital Altitude Preselect (DAP) is available for the Century 2000 and Century 41 autopilot systems. It provides the dual function of preselected altitude and an audible tone. It receives altitude information from the aircraft encoding altimeter or blind encoder. The DAP is very easy to program for it's five modes. As the aircraft approaches to within 1,000 feet of the selected altitude the display will flash and give two audible tones. Upon closure of 200 feet from the selected altitude, the display stops flashing and gives one audible tone. At the selected altitude the autopilot will smoothly transition from Arm to Alt Mode to display current encoder altitude.