7.4 7-1 GUIDED MEDIA Guided media, which are those that provide a conduit from one device to another, include twisted-pair cable, coaxial cable, and fiber-optic cable. Twisted-Pair Cable Coaxial Cable Fiber-Optic Cable Topics discussed in this section:
7.6 UTP Used in LAN, DSL, telephone lines to provide voice and data channels. UTP are classified in categories, 1 through 7. One wire carries the signal, the other is the ground reference. By twisting the wires, the effect of unwanted signals is the same on both wires, thus not affecting the difference. The number of twist per inch has some effect on the quality of the cable.
7.13 Fiber-Optic Cables Made of glass or plastic, transmits signal in the form of light. Optical fibers use reflection to guide light through a channel. Multimode: Multiple beams in the core. Single-mode: Highly focused source of light
7.21 7-2 UNGUIDED MEDIA: WIRELESS Unguided media transport electromagnetic waves without using a physical conductor. This type of communication is often referred to as wireless communication. Radio Waves Microwaves Infrared Topics discussed in this section:
7.22 Figure 7.17 Electromagnetic spectrum for wireless communication