In Australia, amateur radio licensing is governed by the Australian Communications and Media Authority (ACMA) under federal regulations. Licences to operate amateur stations are granted to individuals of any age after they demonstrate a knowledge of the appropriate Amateur Operator's Certificate of Proficiency syllabus for their license grade. Operator's licences are divided into different classes, and offer different operating privileges in accordance with the increasing knowledge required per licence class. Over time these classes and their knowledge requirements have changed and there now remain three different classes.