Technical information

W24 Embedded Web Server
2-76 AT+i Commands Reference Manual May 31, 2008
In Host interaction mode, W24 is used to host, serve, and manage web interactions with a remote
web browser on behalf of the embedded device's host processor. The host gains access to the
web-based parameters via AT+i commands sent to W24 through the serial connection..
Figure 2-7: W24 Web Server Modes
The Application Website
The application website is stored in non-volatile memory. It consists HTML code, which can
include links to local or remote web pages, graphic images, text files, Java applets, WAP pages,
and more.
Device manufacturers can design their own embedded website using any web authoring tool. The
W24 implementation supports a maximum website size of 64K. The site is uploaded to W24
through the serial connection, or through W24's configuration website.
Parameter Tags
W24 and host real-time parameters can be referred to in the embedded websites through the use
of Parameter Tags. When Parameter Tags are placed in an HTML web page, actual values are sent
by W24's web server component when the page is served out. Parameter Tags are also used to
change corresponding parameter values from a remote web browser. Syntactically, Parameter
Tags are parameter names enclosed between two (~) characters. If the (~) character needs to be
included in a Web page, two consecutive (~) characters must be used (~~).
The W24 Internet configuration parameters defined in the AT+i API retain their name when used
as Parameter Tags. For example, the value of the TOA AT+i parameter (Send to E-Mail Address)
may be referenced in the website by ~TOA~.
Host Parameter Tags defined by the parameter name <param>, may be referenced in the website
using ~<param>~. <param> can be any freeform parameter name consisting of a single word
that does not include blanks or W24 delimiters. For example, a parameter reflecting a temperature
reading can be called temperature and referenced in the website as ~temperature~.
W24 Configuration Mode
W24 configuration entails monitoring and updating W24 parameter values. By making use of
W24's inherent configuration website, a W24 device can be configured remotely using a standard
web browser in addition to being configurable locally using the Ymodem protocol over the serial
link, via PSTN in a modem environment, or remotely via e-mail. The W24 RPG parameter is
used to password-protect remote W24 parameter updates. See Security and Restrictions.