Chapter 1. The Dialplan

The dialplan is the routing core of an Asterisk server. Its sole role is to look at what is dialed, and route the call to its destination. This is the core of any telephony system and Asterisk is no different.

The dialplan is made up of three elements—extensions, contexts, and priorities. An extension is number or pattern that the dialed number is to be matched against and a context is a collection of extensions (and possibly other included contexts too). Each extension will have one or more priorities, each of which appear on a separate line, and the priority sequence always starts with the priority "1".

If you have read Building Telephony Systems with Asterisk, you will know how to use extensions, priorities, contexts, and included contexts to handle incoming and outgoing calls as well as to set up features such as:

In this chapter, we will build on this knowledge by looking at:

We will then use this knowledge to provide examples of: