ne 500." However, if one checked the "Fortune 100 Utilities," the Bell System was up on the top. Transferring this information to the "Fortune 500" put Bell System as the leader on the list. We know it is big business; but what is telecommunications? Webster's (Ref. 1) calls it communications at a distance. The IEEE Standard Dictionary (Ref. 2) defines telecom- munications as the transmission of signals over long distance, such as by telegraph, radio, or television. Another term we often hear is electrical communication. This is a descriptive term, but of somewhat broader scope. Some take the view that telecommunication deals only with voice telephony, and the typical provider of this service is the local telephone company. We hold a wider interpretation. Telecommunication encompasses the electrical communication at a distance of voice, data, and image information (e.g., TV and facsimile). These media, therefore, will be major topics of this book. The word media (medium, singular) also is used to describe what is transporting telecommunication signals. This is termed transmission media. There are four basic types of medium: wire pair, coaxial cable, fiber optics, and radio. 1.2 TELECOMMUNICATION WILL TOUCH EVERYBODY In industrialized nations, the telephone is accepted as a way of life. The telephone is connected to the public switched telecommunications network (PSTN) for local, national, and international voice communications. These same telephone connections may also The source for the data in this paragraph is the (US) FCC Study on Telephone Trends 2004. Fundamentals of Telecommunications, Second Edition, by Roger L. Freeman ISBN 0-471-71045-8 Copyright © 2005 by Roger L. Freeman INTRODUCTORY CONCEPTS carry data and image information (e.g., television). In the United States the connection to the PSTN may be via a local exchange carrier (LEC) or by a competitive local exchange carrier (CLEC). The personal computer (PC) is beginning to take on a role similar to that of the telephone-namely, being ubiquitous. Of 