ISO 4217 codes (STANAG 1059, 9th edition) use "X" codes for imaginary exercise countries ranging from XXB for "Brownland" to XXR for "Redland", as well as for major commands such as XXE for SHAPE or XXS for SACLANT. Consequently, ISO 4217 can use "X" codes for non-country-specific currencies without risk of clashing with future country codes. The inclusion of EU (denoting the European Union) in the ISO 3166-1 reserved codes list, allows the euro to be coded as EUR rather than assigned a code beginning with X, even though it is a supranational currency. The ISO 4217 standard includes a crude mechanism
International Organization for Standardization International Organization for Standardization The International Organization for Standardization (ISO ) is an international standard-setting body composed of representatives from various national standards organizations. Founded on 23 February 1947, the organization promotes worldwide proprietary, industrial and commercial standards. It is headquartered in Geneva, Switzerland, and works in 162 countries. It was one of the first organizations granted general consultative status with the United Nations Economic and Social Council. The International Organization for Standardization is an independent, non-governmental organization, the members of which are the standards organizations of the 168 member countries. It is the world's largest developer of voluntary international