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The content in chapter 5 explain basic data transmission concepts, including full duplexing, attenuation, latency, and noise; describe the physical characteristics of coaxial cable, STP, UTP, and fiber-optic media; compare the benefits and limitations of different networking media;. | Transmission Basics Transmit - Issue signals along network medium Transmission - Process of transmitting - Signal progress after transmitted Transceiver - Transmit and receive signals 9 7 2011 Objectives Explain basic data transmission concepts including full duplexing attenuation latency and noise Describe the physical characteristics of coaxial cable STP UTP and fiber-optic media Compare the benefits and limitations of different networking media Explain the principles behind and uses for serial connector cables Identify wiring standards and the best practices for cabling buildings and work areas Analog and Digital Signaling Important data transmission characteristic - Signaling type analog or digital Volt - Electrical current pressure Electrical signal strength - Directly proportional to voltage - Signal voltage Signals - Current light pulses electromagnetic waves 1 t . Voltage V Amplitude 9 2 25 .5 75 ỉ 2 3 -5V . n 1 Figure 3-1 An example of an analog signal Analog data signals - Voltage varies continuously - Properties Amplitude frequency wavelength phase 9 7 2011 Analog and Digital Signaling cont d. Amplitude - Analog wave s strength Frequency - Number of times amplitude cycles over fixed time period - Measure in hertz Hz Wavelength - Distance between corresponding wave cycle points - Inversely proportional to frequency - Expressed in meters or feet Analog and Digital Signaling cont d. Analog signal benefit over digital - More variable Convey greater subtleties with less energy Drawback of analog signals - Varied and imprecise voltage Susceptible to transmission flaws Digital signals - Pulses of voltages Positive voltage represents a 1 Zero voltage represents a 0 2 Figure 3-3 An example of a digital signal Binary system - 1s and Os represent information Bit binary digit - Possible values 1 or 0 - Digital signal pulse Data Modulation Data relies on digital transmission Network connection may handle only analog signals Modem - Accomplishes translation - .
