The FCC's GMDSS / Radio Operator (DO) license is required for those serving as ship radio officers. The GMDSS Radio Maintainer (DM) license is required for those who certify and repair this saftey equipment. Windows CDROM software allows you to study at your PC and take practice exams. Included is the GMDSS booklet which contains the current FCC Elements 7 & 9 questions from the question pools.