This European Standard specifies sets of data presented at an interface, the card sub-system interface, in a structured form as well as the rules for dealing with that data to enable products such as tickets to be written to a Machine Readable Card in a manner which will minimise the amount of data to be held on the card while allowing an authorised party to be able to access and interpret the data easily and efficiently.This is the basis for practical interoperability and as such, this European Standard forms the foundation of interoperability across systems subject to commercial agreements and interchange of details concerning how this European Standard has been physically interpreted. As part of this capability, the design of the data environment allows for the addition of new sets of data to represent new or modified transport products without compromising the ability of existing terminals to continue to handle all sets of data held on the card, whether or not they are to be interpreted and possibly used.Associated with the data is the set of processes which applies to the data within the application. The inclusion of process in the standard means that similar data will be treated in a similar way by all external services and terminals leading to true interoperability that can be achieved and maintained through this European Standard. In addition, acknowledgement that the application specifies both data and process also implies that it needs to consider security both at the level of access rights to data and the security of the overall environment in which it operates.