 These are established codes for determining the seniority of officer and other ranks in NATO countries for a particular joint task group or command structure, although specific appointments designate a higher level of seniority over other equivalent rank codes in a given situation.Officer ranks go from OF-1 (applying to all subaltern officers below captain) up to OF-10; OF(D) being a special category for trainee officers awaiting a commission.Other Ranks (those considered enlisted men in the United States forces) are classified from OR-1 to OR-9.