ISO 4217 "ruble". In addition to codes for most active national currencies ISO 4217 provides codes for "supranational" currencies, procedural purposes, and several things which are "similar to" currencies: The use of an initial letter "X" for these purposes is facilitated by the ISO 3166 rule that no official country code beginning with X will ever be assigned. Because of this rule ISO 4217 can use X codes without risk of clashing with a future country code. ISO 3166 country codes beginning with "X" are used for private custom use (reserved), never for official codes. For instance, the ISO 3166-based NATO country
ISO Standards for colour ink jet printers ISO Standards for colour ink jet printers In 2009, the ISO (International Organization for Standardization) published the International Standard for determining the ink cartridge yield for colour inkjet printers and multifunctional devices. This standard is used to prescribe the test method that manufacturers and test labs use to determine ink jet cartridge yields. It also standardizes the appropriate method of describing the yield of cartridges in documentation supplied to the consumer by the manufacturer. Manufacturers of printers or devices that use colour ink jet technology are meant to abide by this standard when testing for, and labeling the estimated yields