Book Image

Asterisk 1.4 - The Professional's Guide

Book Image

Asterisk 1.4 - The Professional's Guide

Overview of this book

Asterisk is the leading Open Source Telephony application and PBX software solution. It represents an effective, easy-to-administer, and accessible platform for running enterprise telephony requirements. The real world, however, offers numerous hurdles when running Asterisk in the commercial environment including call routing, resilience, or integrating Asterisk with other systems. This book will show you some of the ways to overcome these problems. As the follow-up to Packt's highly successful 2005 title Building Telephony Systems with Asterisk, this book presents the collected wisdom of Asterisk Professionals in the commercial environment. Aimed at Administrators and Asterisk Consultants who are comfortable with the basics of Asterisk operation and installation, this book covers numerous hands-on topics such as Call Routing, Network Considerations, Scalability, and Resilience ñ all the while providing practical solutions and suggestions. It also covers more business-related areas like Billing Solutions and a Winning Sales Technique. Even if your interest or experience with Asterisk is lower level, this book will provide a deeper understanding of how Asterisk operates in the real world. Asterisk is deployed across countless enterprises globally. Running on Linux, it has constantly demonstrated its resilience, stability, and scalability and is now the advanced communication solution of choice to many organizations and consultants. With a foreword from Mark Spencer, the man behind Asterisk, this book presents the accumulated wisdom of three leading Asterisk Consultants and shows the reader how to get the most out of Asterisk in the commercial environment. Over the course of eleven chapters, this book introduces the reader to topics as diverse as Advanced Dial Plans, Network Considerations, and Call Routing, through to Localization, DAHDI, Speech Technology, and Working with a GUI. The book also covers the more nebulous aspects of being an Asterisk professional such as evaluating customer requirements and pitching for contracts. This book represents the wisdom and thoughts of front line consultants. The knowledge they impart will prove informative, thought provoking and be of lasting interest to Asterisk professionals.
Table of Contents (20 chapters)
Asterisk 1.4
Credits
Foreword
About the Authors
About the Reviewers
Preface
9
Interfacing with Traditional Analog and Digital Telephony
Sample Appointment Sheet

Implementation considerations


So now you know we are going to home in on ASR and TTS for use with Asterisk. Both of these can be quite hungry in terms of processing power and memory usage be sure to use some reasonable horse-power if you are serious about implementing speech technology. At least 2GB RAM with a 2GHz CPU would be a good start.

For this reason, most providers of speech engines use a client/server architecture to allow speech processing to occur on other (perhaps more powerful) machines than that on which the telephony application is running although this will not always prove necessary.

ASR and Asterisk

There are a number of options for adding speech recognition to Asterisk and these include Sphinx and LumenVox. For our example, we will go with LumenVox as it makes use of the native speech recognition API (application programming interface) that has been part of Asterisk since version 1.4 was released.

This API allows providers of speech engines to hook their software into Asterisk...