Product Description
This book explains why people and companies are converting some or all of their existing (legacy) telephone systems from dedicated telephone systems (such as proprietary PBX) to more standard IP telephony systems. These conversions allow for telephone bill cost reduction, increased ability to control telephone services, and the addition of new telephone information services. Through the use of IP telephony service, companies can immediately reduce their telecommunication costs 40% to 70%. This book provides an overview of the different types of IP Telephony systems including IP PBX, IP Centrex and Internet Telephone systems. You will learn the key functional parts of voice over IP systems and how voice over Internet protocol (VoIP) systems work. Explained are the processes used to setup and control IP telephony service. The common IP Telephony protocols including session initiation protocol (SIP), Media Gateway Control Protocol (MGCP) and H.323 are desc… More >>

Introduction to IP Telephony: Why and How Companies are Upgrading Private Telephone Systems to use VoIP Services, Second Edition