From MAPGPS on the arDrone api forum: https://projects.ardrone.org/boards/1/topics/show/852
Setings: AT*CONFIG=1,\"control:altitude_max\",\"2000\"
Basic controls
Takeoff: AT*REF=101,290718208
Landing: AT*REF=102,290717696
Hovering: AT*PCMD=201,1,0,0,0,0
Of course the first parameter (101,102,etc..) should be replaced with the correct sequence number.