Chapter 3 ITM 301 Mid Term NotesSummary Notes:- Information can be transmitted via two methods: analog or digital. Analog signals arecontinuous waves that result in variable and inexact transmission. Digital signals arebased on electrical or light pulses that represent information encoded in binary form.-In half-duplex transmission, signals can travel in both directions over a medium but inonly one direction at a time. When signals can travel in both directions over amedium simultaneously, the transmission is considered full-duplex.-A form of transmission that allows multiple signals to travel simultaneously over onemedium is known as multiplexing. In multiplexing, the single medium is logicallyseparated into multiple channels, or subchannels.-Throughput is the amount of data that the medium can transmit during a givenperiod of time. Throughput is usually measured in bits per second and depends on thephysical nature of the medium.-Baseband is a form of transmission in which digital signals are sent through directcurrent pulses applied to the wire. Baseband systems can transmit only one signal, or one channel, at a time. Broadband, on theother hand, uses modulated analogfrequencies to transmit multiple signals over the same wire.-Noise is interference that distorts an analog or digital signal. It may be caused byelectrical sources, such as power lines, fluorescent lights, copiers, and microwaveovens, or by broadcast signals.- Analog and digital signals both suffer attenuation, or loss of signal, as they travelfarther from their sources. To compensate, analog signals are amplified, and digitalsignals are regenerated through repeaters.-Every network is susceptible to a delay between the transmission of a signal and itsreceipt. This delay is called latency. The length of the cable contributes to latency, asdoes the presence of any intervening connectivity device.-Coaxial cable consists of a central metal conducting core (often copper) surrounded by aplastic insulator, a braided metal shielding, and an outer plastic cover called the sheath.The conducting core carries the electromagnetic signal, and the shielding acts as both aprotection against noise and a ground for the signal. The insulator layer protects thecopper core from the metal shielding. The sheath protects the cable from physical damage.-Most networks no longer rely on coaxial cable; however, if you obtain Internet service from a cable company, the cable that enters your home will be a type of coax known as RG-6.-Twisted pair cable consists of color-coded pairs of insulated copper wires, each with adiameter of 0.4 to 0.8 mm, twisted around each other and encased in plastic coating.-STP (shielded twisted pair) cable consists of twisted-wire pairs that are not onlyindividually insulated, but also surrounded by a shielding made of a metallicsubstance such as foil to reduce the effects of noise on the signal.