1. Overview

The file is located in the /etc/asterisk/ directory.

The extensions.conf file is one of the most used and most important configuration file in Asterisk PBX - it contains the dialplan. What is a dialplan? The dialplan , or we can say "the heart of the Asterisk System", defines how Asterisk PBX will handle incoming and outgoing calls, it also contains all extension numbers. The dialplan is divided in sections called contexts. Every context consists from more than one extensions. What is an extension? The extension is the telephone number, it can be numbers, letters or both. Every extension has a priority and an application. With the help of contexts we can organize our dialplan.

In general a dialplan looks like this:



2. Contexts
2.1 [general]


2.2 [globals]

2.3 "Real" call contexts

3. Extension
Extension = telephone number? Yes, in general it is true.There are three types of extensions : litteral, predifined and pattern.

The litteral extensions can contain in their name: numbers (0-9), letters A,B,C,D (some hardphones have these letters) or all letters (a-z). Are extension names case sensitive? Yes and no. They are case sensitive when Asterisk have to match a user dialed extension to the extensions that are defined in a context. Extension names are not case sensitive when you try define two extensions (in one context) with same name but different case (you can not do this).

There are several predefined extension names:


Example:


If extension name starts with '_', it is consider as pattern.
For the extension that use pattern, some characters have special meaning:


Note: Do not use '_.', because it will match everything even the predefined extensions!!!

Example:


So you can see that with help of patterns you can group calls as national, international or local, the only thing you must do is to write the pattern.

4. Other very useful stuff included in extensions.conf
4.1 ignorepad
4.2 switch

4.3 include