Eliot Christian, United States Geological Survey XER: the XML Encoding Rules (abstract) There are several communities that develop network protocols that are themselves defined using ASN.1 (Abstract Syntax Notation) together with encoding rules such as BER (Basic Encoding Rules). Especially relevant to this conference is the Information Search and Retrieval protocol, ANSI Z39.50/ISO 23950. ASN.1 specifies tag, length, value data structures to comprise protocol data units. The basic idea of XER (XML Encoding Rules) is to standardize rules for transforming appropriate ASN.1 encoded data structures into equivalent XML data structures and vide versa. For developer communities making significant investments in XML, XER may leverage investments already made in ASN.1-based applications and thereby preserve the hard-won interoperability already achieved among such applications. For developer communities currently using ASN.1, XER may leverage investments being made in XML-based applications becoming widespread on the Internet. Information about XER is available at ----------------------------------------------------------------------