XML (eXtensible Markup Language)

An internet specification for web documents that enables tags to be used that provide functionality beyond that in Hyper Text Markup Language (HTML). In contrast to HTML XML has the ability to allow information of indeterminate length to be transmitted to a PSAP call taker or dispatcher versus the current restriction that requires information to fit the parameters of pre-defined fields.

eXtensible Markup Language (XML) instance document

An XML document that conforms to a given schema, as a specific instance of that schema.

eXtensible Markup Language (XML) Schema

The formal document definition (structure, content type and constraints) describing a class of XML instance documents. There are various XML schema languages, but in this document, all schemas are assumed to be defined using the W3C XML Schema definition language.