Integrated mail processing (IMP) is the method that Royal Mail uses to sort the mail (in bulk) before delivery and has been implementing the technology since 1999. The system works by automated optical character recognition of postcodes. Integrated mail processors scan the front and back of an envelope and translate addresses into machine-readable code. Letters are given a fluorescent orange barcode that represents the address. The barcode follows the RM4SCC pattern. Per mail item there are over 250 types of information that are collected from mail class to indicia type. Some scanning and detection features have been removed as they have been superseded by newer technology. This is known as the IMP Extension of Life (EoL) program.