tents 6.8.6 Applications and Future of ATM Problems and Review Questions References Future Developments in Telecommunications Information Networks Telephone Services Wireless Communications Optical Technology Digital Broadcast Systems Summary About the Author Index Preface Telecommunications is one of the fastest growing business sectors of modern information technologies. A couple of decades ago, to have a basic under- standing of telecommunications, it was enough to know how the telephone network operated. Today, the field of telecommunications encompasses a vast variety of modern technologies and services. Some services, such as the fixed telephone service in developed countries, have become mature, and some have been exploding (e.g., cellular mobile communications and the Internet). The deregulation of the telecommunications industry has increased business growth, even though, maybe because, tariffs have decreased. The present telecommunications environment, in which each of us has to make choices, has become complicated. In the past, there was only one local telephone network operator that we chose to use or not use. Currently, many operators offer us ADSL or cable modem for Internet access and we have many options for telephone service as well. Telecommunications is a strategically important resource for most modern corporations and its importance continues to increase. Special atten- tion has to be paid to the security aspects and costs of services. The ever- changing telecommunications environment provides new options for users, and we should be more aware of telecommunications as a whole to be able to capitalize on the possibilities available today. The business of telecommunications has been growing rapidly, and many newcomers have found employment in this area. Even if these Introduction to Telecommunications Network Engineering newcomers have a technical background, they may feel that they have a very restricted overall view of the telecommunications network as a whole. The first purpose of this book 