Data exchange systems comprising portable data processing units

The data exchange system comprises at least one portable processing unit (5), the (5) comprises the communication device (14), processing (15) and a storage unit (16), wherein the rear comprises an input actuating (17) and one or more application descrptors (18(1) than 18 (n)), the application descriptions comprises at least one correlation context (19(1) than), The context a command and data element and data quotation, process, state of access and an; andThe so as to achieve such as the intelligent card and a on limited storage space in the manner of selecting data element and data of quotations and quotation the structure of efficient is.