Book Image

Building Telephony Systems With Asterisk

By : Barrie Dempster, David Gomillion
Book Image

Building Telephony Systems With Asterisk

By: Barrie Dempster, David Gomillion

Overview of this book

<p>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 station-to-station calls, line trunking, call distribution, call detail rerecords, and call recording.<br /> <br /> Asterisk can be used to provide Interactive Voice Response (IVR). The power and flexibility of a programmable phone system gives us the ability to respond to our customers in meaningful ways. <br /> <br /> Asterisk has also a fully-functional voicemail system included. It supports voicemail contexts so that multiple organizations can be hosted from the same server.&nbsp; It supports different time zones so that users can track when their phone calls come in.&nbsp; It even provides the option to notify the recipient of new messages via email.&nbsp; In fact, we can even attach the message in audio!<br /> <br /> Finally, Asterisk is a Voice Over IP (VoIP) system. The benefits of VoIP are numerous. For instance, we can have multiple users using the same Asterisk service from a variety of locations; we can have users in the local office using PSTN phones or IP phones; we can have remote VoIP users; we can even have entire Asterisk systems operated and run completely separately but with integrated routing; We can have an extension anywhere we have a reasonably fast Internet connection, which means employees can have an extension on the phone system at home if they have a broadband connection. The benefits are too many to list.<br /> <br /> Flexibility often means complexity, and this is true in the case of Asterisk. 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.</p>
Table of Contents (14 chapters)
Copyright
Credits
About the Reviewers
About the Authors
Introduction

Introduction

Telephony systems are an integral part of business, and it's important that the framework used is flexible enough to cover as many areas of application as possible, and at the same time is user friendly. This book is an attempt at exploring one such system—Asterisk.

What This Book Covers

Chapter 1 introduces Asterisk and talks about the possible scenarios that would demand its usage, and the realistic trade-offs that you should consider when choosing it.

Chapter 2 discusses a basic deployment plan, and takes you through various aspects such as requirements and the how-tos of choosing the right terminal equipment and hardware.

Chapter 3 discusses installation of Asterisk. It starts with a section on preparing a system for installation, takes you through installation of necessary components, and ends with an introduction to the way Asterisk behaves.

Chapter 4 deals with the basic Asterisk configuration, and discusses the Zaptel interfaces in detail, and then the configuration of protocols and various features.

Chapter 5 deals with creating a dialplan. This involves creating a context and extensions, and the chapter also discusses advanced call distribution and automatic attendants.

Chapter 6 discusses quality assurance issues that concern most companies, and gives an overview of call detail records, call monitoring, and recording, etc.

Chapter 7 talks about Asterisk@Home—a simplified Asterisk solution that retains most of its functionality for its so-called "home" users—and a customer relationship management system, SugarCRM.

In Chapter 8 we've shown a few case studies of working Asterisk-based phone systems, and have discussed scenarios for home offices and small businesses.

Chapter 9 deals with Asterisk's maintenance and security aspects. The topics range from backups of configuration files to disaster management plans to server security. This chapter also discusses Asterisk's scalability aspects and support channels.

Conventions

In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

There are three styles for code. Code words in text are shown as follows: "We can include other contexts through the use of the include directive."

A block of code will be set as follows:

[default]
exten => s,1,Dial(Zap/1|30)
exten => s,2,Voicemail(u100)
exten => s,102,Voicemail(b100)
exten => i,1,Voicemail(s0)

When we wish to draw your attention to a particular part of a code block, the relevant lines or items will be made bold:

[default]
exten => s,1,Dial(Zap/1|30)
exten => s,2,Voicemail(u100)

exten => s,102,Voicemail(b100)exten => i,1,Voicemail(s0)

Any command-line input and output is written as follows:

# cp /usr/src/asterisk-addons/configs/cdr_mysql.conf.sample     /etc/asterisk/cdr_mysql.conf

New terms and important words are introduced in a bold-type font. Words that you see on the screen, in menus or dialog boxes for example, appear in our text like this: "clicking the Next button moves you to the next screen".

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