An overview of a data interchange is shown in Figure 34. System A wants to send a dataset to system B. To ensure a successful interchange A and B must decide on three things, i.e. a common application schema I, which encoding rule to apply R and what kind of transfer protocol to use. The application schema is the basis of a successful data transfer and defines the possible content and structure of the transferred data, whereas the encoding rule defines the conversion rules for how to code the data into a system independent data structure.