Grandstream GXP21xx XML Application Guide - Manual (Page 5)

FIRMWARE VERSION 1.0.4.23 GXP21xx XML APPLICATION GUIDE Page 5 of 36
WHAT IS XML
XML (eXtensible Markup Language) is a markup language* for documents and applications containing
structured information. This information contains both content (text, pictures, input box and etc.) and an
indication of what role that content plays (e.g. content in a section header is different from content in a
footnote, or content in a figure caption, or content in a database table, etc.). Almost all documents have
certain kind of structure.
*A markup language is a mechanism to identify structures in a document. The XML specification defines a
standard way to add markup to documents.
WHY XML
What benefits does XML provide to SIP endpoints? XML enables our SIP phones to serve as output
devices for web services and other online applications. The XML infrastructure allows the phones to
interact with external applications in a flexible and programmable manner. Three specific XML API
supported by GXP21xx are XML Custom Screen, XML Phonebook and XML Application.
XML API ARCHITECTURE
The XML application on GXP21xx is using HTTP/HTTPS as the transport protocol. The following figure
shows how it works. Basically, GXP21xx initiates the HTTP/HTTPS GET Request to the server and waits
for the response. Once the phone receives the response with XML content in BODY, it displays the
information.
Two types of XML API architecture are introduced below, depending on if the application is within LAN or
accessed via Internet.