This Recommendation is part of the set of Specification and description language Recommendations for SDL-2008. It adds the data and action language used to define data types and expressions. In SDL-2008 it is allowed to use different concrete data notations, such as the SDL-2000 data notation or C with bindings to the abstract grammar and the predefined data package. This Recommendation is revised to be consistent with the rest of the Z.100 series for SDL-2008. It replaces the data part of ITU-T Z.100 for SDL-2000 and previous ITU-T Z.104 on encoding of data.