21.1 Introduction

Transmission media, the interconnect pathway that ties together all associated communications hardware, must be considered an integral part of the communications network. The media, commonly referred to as cabling, is that part of the communications network that is buried in the ground, hidden behind walls, or run between floors at a relatively high installation cost. Swapping out a computer or workstation is fairly easy, but changing the wiring in a building is difficult and expensive. State-of-the-art building designs provide for communications network requirements and adhere to building wiring standards. [1 -4 ]

This chapter reviews the two dominant transmission types, copper and fiber optic cabling. The copper cable types considered are coaxial shielded and unshielded twisted-pair. Fiber optic cable, a flexible strand of glass, is either of the single-mode or multimode type. These cable-specific types, along with their physical characteristics, are defined subsequently in this chapter. The transmission line theory for each cable type is discussed and referenced.

Wireless also is a means of communication. The phrase wireless media, or communication via radio waves through air or a vacuum, is confusing; "wireless cabling" is a contradiction in terms. The reader should refer to the specific wireless technology of interest to gain an understanding of its inherent transmission characteristics.

21.2 Copper Media

Copper media...