Chapter 3. Programming in the dialplan

In Asterisk, functions or programs can be implemented either externally, through an AGI script (in much the same way that a CGI script can add functionality to a web page) or internally, through functions and applications in the dialplan. This chapter will focus strictly on the internal functions; AGI is treated in depth in a separate chapter.
The dialplan is defined in the extensions.conf configuration file. The dialplan itself looks much like a BASIC program. The administrator can implement features and call flow using a simple scripting language.