Describes the use, implementation, and maintenance procedures for the Data Reconfiguration Service (DRS) Compiler that reformats messages passing between dissimilar computers in real time. Several ARPANET sites will provide the DRS so that the reconfiguration service can be compared and contrasted with current operations requiring standard data representations for user and server. The compiler processes descriptions of data reconfigurations as instructions for reformatting the data entailing a lexical scan of the reconfiguration definition, a syntactic verification of the resulting lexical units, and the generation of instructions for the interpreter. It operates through a file system to retrieve descriptions and emit the instruction sequence. Emphasis is on expediting implementation rather than on producing a fast compiler or highly efficient instructions. (See also R-860.) 127 pp.