ciations Functional Standards Groups Conformance Independent Testing Test Houses Figure 1.21 The standards-making process Chapter 1 Telecommunications Technology Fundamentals Table 1.2 Standards Organizations Region Standards Organizations International ITU, ITU-T, ITU-R, ITU-D, IEC, ISO Australia ACA, ACC, AIIA, ATUG Europe AFNOR (France), CEN and CENLEC, CEPT, DIN (Germany), DTI (UK), ETSI, European Community (EU) Japan JISC, TTC New Zealand ITANZ North America ANSI (USA), EIA, FCC (USA), IEEE, NIST, SCC (Canada) Chapter Traditional Transmission Media Transmission media are the physical pathways that connect computers, other devices, and people on a network-the highways and byways that comprise the informa- tion superhighway. Each transmission medium requires specialized network hard- ware that has to be compatible with that medium. You have probably heard terms such as Layer 1, Layer 2, and SO on. These refer to the OSI reference model, which defines network hardware and services in terms of the functions they perform. (The OSI reference model is discussed in detail in Chapter 5, "Data Communica- tions Basics.") Transmission media operate at Layer 1 of the OSI model: They encompass the physical entity and describe the types of highways on which voice and data can travel. It would be convenient to construct a network of only one medium. But that is impractical for anything but an extremely small network. In general, networks use combinations of media types. There are three main categories of media types: Copper cable-Types of cable include unshielded twisted-pair (UTP), shielded twisted-pair (STP), and coaxial cable. Copper-based cables are inexpensive and easy to work with compared to fiber-optic cables, but as you'll learn when we get into the specifics, a major disadvantage of cable is that it offers a rather limited spectrum that cannot handle the advanced applications of the future, such as teleimmersion and virtual reality. Wireless-Wireless media include radio frequencies, microwave, satellite, and infra