|  | Overview
Networking media is literally and physically the backbone of a network. Inferior quality of network cabling results in network failures and unreliable performance. Copper, optical fiber, and wireless networking media all require testing to determine the quality. These tests involve certain electrical and mathematical concepts and terms, such as signal, wave, frequency, and noise. Understanding this vocabulary is helpful when learning about networking, cabling, and cable testing. The goal of the first lesson in this module is to provide some basic definitions so that the cable testing concepts presented in the second lesson will be better understood. The second lesson of this module describes the issues relating to the testing of media used for physical layer connectivity in local-area networks (LANs). In order for the LAN to function properly, the physical layer medium must meet the industry standard specifications. Attenuation (signal deterioration) and noise (signal interference) cause problems in networks because the data is not recognizable when it is received. Proper attachment of cable connectors and proper cable installation are important. If standards are followed in these areas, attenuation and noise levels are minimized. After cable has been installed, it must be tested with quality cable testers to verify that the specifications of the TIA/EIA standards are met. This module also describes the various important tests that are performed. Students completing this module should be able to: Differentiate between sine waves and square waves Define and calculate exponents and logarithms Define and calculate decibels Define basic terminology related to time, frequency, and noise Differentiate between digital bandwidth and analog bandwidth Compare and contrast noise levels on various types of cabling Define and describe the affects of attenuation and impedance mismatch Define crosstalk, near-end crosstalk, far-end crosstalk, and power sum near-end crosstalk Describe how crosstalk and twisted pairs help reduce noise Describe the ten copper cable tests defined in TIA/EIA-568-B Describe the difference between Category 5 and Category 6 cable