Book Image

Asterisk 1.6

Book Image

Asterisk 1.6

Overview of this book

Asterisk is a powerful and flexible open source framework for building feature-rich telephony systems. As a Private Branch Exchange (PBX) which connects one or more telephones, and usually connects to one or more telephone lines, Asterisk offers very advanced features, including extension-to-extension calls, queues, ring groups, line trunking, call distribution, call detail rerecords, and call recording. This book will show you how to build a telephony system for your home or business using this open source application. 'Asterisk 1.6' takes you step-by-step through the process of installing and configuring Asterisk. It covers everything from establishing your deployment plan to creating a fully functional PBX solution. Through this book you will learn how to connect employees from all over the world as well as streamline your callers through Auto Attendants (IVR) and Ring Groups.This book is all you need to understand and use Asterisk to build the telephony system that meets your need. You will learn how to use the many features that Asterisk provides you with. It presents example configurations for using Asterisk in three different scenarios: for small and home offices, small businesses, and Hosted PBX. Over the course of ten chapters, this book introduces you to topics as diverse as Public Switched Telephony Network (PSTN), Voice over IP Connections (SIP / IAX), DAHDI, libpri, through to advanced call distribution, automated attendants, FreePBX, and asterCRM. With an engaging style and excellent way of presenting information, this book makes a complicated subject very easy to understand.
Table of Contents (15 chapters)
Asterisk 1.6
Credits
About the Authors
About the Reviewer
Preface

Creating a context


What is a context? Simply said, a context is a group of extensions. Each extension must exist within a context. There is more to contexts than grouping extensions though.

In our extensions.conf file (or any included files), a context is denoted by square brackets "[ ]", as shown:

[mycontext]
. . .

So, if a context is a group of extensions, why do we need more than one? Let's think for a minute. Not all employees should be able to dial every phone. Would you trust your 16-year-old intern with the ability to dial international calls? I wouldn't. Also, do you want your president to be bothered by customers in the waiting room who use a courtesy phone and misdial? We could find that hazardous to our continued employment.

Certain extensions are hidden or made inaccesible from other extensions by context. This gives us some level of security. It also allows us to host multiple phone systems on a single server.

Imagine you have two businesses on the same phone system, each with...