This property appears in exactly 3 places in the DFDL spec. * Section 13.5 where it is defined * Appendix G: 36.1 Parser - property precedence tables * Appendix G: 36.2 Unparser - property precedence tables. The definition in Section 13.5 says Indicates whether an xs:decimal element is signed. See 13.6.2 Converting logical numbers to/from text representation and 13.7.1 Converting Logical Numbers to/from Binary to see how this affects the presence of the sign in the data stream. 'yes' means that the xs:decimal element is signed 'no' means that the xs:decimal element is not signed Neither Section 13.6.2 nor 13.7.1 mention the decimalSigned property. We need to add language which clarifies this. I believe this is roughly what is needed: In Section 13.6.2, add this material at the start of the section: *The signed number types are byte, short, int, long, integer, float, double* *The unsigned number types have names beginning with "unsigned", as well as nonNegativeInteger.* *For type xs:decimal the decimal is considered signed if dfdl:decimalSigned="yes" and unsigned if dfdl:decimalSigned="no". * In Section 13.7.1 we need to add this: *When dfdl:binaryNumberRep="binary", then dfdl:decimalSigned controls whether the underlying representation is interpreted as a twos-complement signed binary integer or an unsigned binary integer. This value is then scaled using dfdl:binaryDecimalVirtualPoint to convert to/from the infoset value. * *When dfdl:binaryNumberRep is 'bcd', no sign is possible and the dfdl:decimalSigned property is ignored. * *When dfdl:binaryNumberRep is 'packed' a sign nibble is required and the dfdl:decimalSigned property is ignored.* *(rationale: packed but unsigned is the same as BCD)* *When dfdl:binaryNumberRep is "ibm4690Packed" the dfdl:decimalSigned property is used to determine if negative values are allowed, i.e., the packed digits may be preceded by a negative sign nibble.* *If dfdl:decimalSigned is "no" then no sign nibble is expected or allowed. * Mike Beckerle Apache Daffodil PMC | daffodil.apache.org OGF DFDL Workgroup Co-Chair | www.ogf.org/ogf/doku.php/standards/dfdl/dfdl Owl Cyber Defense | www.owlcyberdefense.com