The Dialplan is a crucial part of any FreeSWITCH installation. Indeed, any PBX must have a Dialplan, sometimes called a numbering plan, in order to handle the routing of calls. In simple terms, a Dialplan is a list of instructions on where to route a call. For example, when a user picks up a phone and dials 1000, how does the system know what to do with that call? The example Dialplan knows to connect the calling party to the telephone registered as user ID 1000. However, the Dialplan can do much more than merely connect the calling and called parties. The Dialplan contains instructions on what the call should do and how it should behave.
In the previous chapter we made small modifications to the Dialplan. In this chapter, we will build upon that foundation and introduce the basics of routing and controlling calls as we discuss the following topics:
Overview of the XML Dialplan
Contexts, extensions, and actions
Conditions, patterns, and regular expressions...