The ITU Radio Regulations (short: RR) regulates on law of nations scale radiocommunication services and the utilisation of radio frequencies. It is the supplementation to the Constitution and Convention of the International Telecommunication Union (ITU Constitution and Convention). In line to the ITU Constitution and Convention and the ITU International Telecommunication Regulations (ITR), this ITU Radio Regulations belong to the basic documents of the International Telecommunication Union. The ITU Radio Regulations comprise and regulate the part of the allocated electromagnetic spectrum (also: radio frequency spectrum) from 9 kHz to 275 GHz.