Network+ Guide to Networks 7th ed. Quiz Ch. 5 – Flashcards
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A device that is responsible for modulating digital signals into analog signals, and demodulating analog signals into digital signals at the receiving end, is known as?
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A modem
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What type of cross-talk occurs between wire pairs near the source of a signal?
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near end cross talk
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What is modulation? Provide two examples of how it can be used.
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Modulation is technology used to modify analog signals to make them suitable to carry data over a communication path. In modulation, the simple wave, called carrier wave, combines with another analog signal - the information or data wave - to produce a unique signal that gets transmitted from one node to another. Modulation can be used to make a signal conform to a certain path. For example, FM (Frequency Modulation) radio - the frequency of the carrier signal is modified by the application of the data signal. AM (Amplitude Modulation) radio - the amplitude of the carrier signal is modified by the application of the data signal.
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Digital signals are composed of pulses of precise, positive voltages and zero voltages.
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True
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___________ causes problems only when a receiving node is expecting some type of communication, such as the rest of the data stream it has begun to accept.
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Latency
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A __________ is a device that retransmits a digital signal in its original form, extending the length of a segment.
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repeater
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Because digital signals do not depend on amplitude or frequency differences to communicate information, they are more vulnerable to EMI noise.
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False
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The amount of data that a medium transmits during a given period of time.
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throughput
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Cross-talk measured at the far end of the cable from the signal source.
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far end cross-talk (FEXT)
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A term used to refer to a type of twisted-pair cable. All of the category cables fall under the TIA/EIA 568 standard.
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Cat (category)
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A form of transmission that allows multiple signals to travel simultaneously over one medium.
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multiplexing
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The distance between corresponding points on a wave's cycle, expressed in meters or feet.
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wavelength
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An unwanted connection, such as when exposed wires touch each other.
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short circuit
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Physical layer standard for networks that specifies 1-Gbps transmission over fiber-optic cable using baseband transmission, relying on 1300 nanometer wavelengths.
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1000Base-LX
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A Physical layer standard for networks that achieves 1 Gbps over Cat 6 or better cabling using only two pairs of wires.
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1000Base-TX
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A character encoding system consisting of 128 characters.
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ASCII
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A multiplexing technique used over single-mode or multimode fiber-optic cable in which each signal is assigned a different wavelength for its carrier wave.
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DWDM (Dense Wavelength Division Multiplexing)
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A continuity tester should not be used on a live network segment.
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True
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Multimode fiber contains a core that is larger than a single mode fiber core.
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True
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Which of the following connectors is the most common for multimode fiber?
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MT-RJ
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A measure of a signal's strength at any given time is known as which term below?
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amplitude
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Using a form of transmission that allows multiple signals to travel simultaneously over one medium is known as which of the following options?
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multiplexing
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What Ethernet standard below is also referred to as "thinnet"?
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10Base2
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What is the minimum category of UTP cable required in order to support Gigabit speeds?
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Cat 5e
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The most common multiplexing technology used in conjunction with fiber optics is which option below?
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DWDM
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A __________ is a voltage, frequency, pulse, or phase change in an analog transmission.
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symbol
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How many cable pairs are needed for 1000Base-T transmission over CAT5e cable?
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4
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Phone companies make use of what type of multiplexing in order to allow for phone services and DSL services over the same line?
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FDM
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Since cable TV and cable Internet can share the same coaxial cable, they are considered to be what type of technology?
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broadband
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A _________ is a simple instrument that can measure many characteristics of an electric circuit, including its resistance, voltage, and impedance.
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multimeter
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What term below is used to describe the outer-most layer of protective covering of a coaxial cable?
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sheath
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Standard PoE devices must be provided with how much power in order to function?
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15.4 watts
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What is the maximum distance for 10GBase-ER and 10GBase-EW on a segment of single mode fiber?
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40km
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What is the maximum supported throughput and bandwidth / signal rate of Cat 5e?
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1000 Gbps, 350 MHz
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Using DWDM, a single fiber can carry between what two numbers of channels?
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80, 160
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What two connector types are typically used to terminate RG-6 and RG-59 cables?
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f-connectors, BNC
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Ethernet is an example of what type of technology?
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baseband
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Which type of multiplexing is defined by wavelength instead of frequency?
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CWDM
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Which option below reflects the standard impedance of an RG-6 cable?
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75 ohms
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The number of times that a wave's amplitude cycles from its starting point, through its highest amplitude and its lowest amplitude, and back to its starting point over a fixed period of time, is known as what term below?
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frequency
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What is the maximum supported throughput of a CAT6 cable?
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10 Gbps
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What two items below are commonly expressed as bits transmitted per second?
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throughput, bandwidth
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WDM divides a beam of light into how many different wavelengths or colors?
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40
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Frequencies used to convey speech over telephone lines fall between what two frequencies below?
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300 Hz, 3.3 KHz
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A _________ cable reverses all of the wires without regard to how they are paired.
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rollover
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A serial cable with an RJ-45 connector is capable of being used through an RJ-45 Ethernet port.
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False
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How does a digital signal compare to an analog signal?
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Digital signals are composed of pulses of precise, positive voltages and zero voltages. It has no infinite or continuous signal because it is inherently either on or off. A pulse of positive voltage represents a 1, and a pulse of zero voltage represents a 0. 1s and 0s represent information as in a binary system. A digital signal pulse is a binary digit, or bit. An analog signal, such as the electromagnetic wave in the air or copper wires, varies infinitely and continuously. A drawback in Analog signals is their infinite variations, which are susceptible to transmission flaws such as noise or the types of interferences that degrades the signal.
