Chapter 5- Network Cabling – Flashcards
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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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A Physical layer standard for networks that achieves 1 Gbps over Cat 6 or better cabling using only twopairs 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 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
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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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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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The distance between corresponding points on a wave's cycle, expressed in meters or feet.
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Wavelength
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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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The amount of data that a medium transmits during a given period of time.
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Throughput
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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
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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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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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What two connector types are typically used to terminate RG-6 and RG-59 cables?
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BNC and F-connectors
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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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A _____________ cable reverses all of the wires without regard to how they are paired.
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Rollover
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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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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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A ______________ is a voltage, frequency, pulse, or phase change in an analog transmission.
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Symbol
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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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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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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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Define how phase affects an analog signal.
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Phase is the progress of a wave over time in relationship to a fixed point. Suppose two separate waves have identical amplitudes and frequencies. If one wave starts at its lowest amplitude at the same time the second wave starts at its highest amplitude, these waves will have different phases. More precisely, they will be 180 degrees out of phase (using the standard assignment of 360 degrees to one complete wave). Had the second wave also started at its lowest amplitude, the two waves would be in phase.
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Describe two ways in which analog and digital signals are boosted.
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amplifier—Analog signals pass through an amplifier, an electronic device that increases the voltage, or strength, of the signals. Unfortunately, the boost can also boost the noise that has accumulated in the signal, which causes the analog signal to worsen progressively. After multiple amplifications, an analog signal may become difficult to decipher. repeater—Recall that a repeater is a device that regenerates a digital signal in its original form, without the noise it might have previously accumulated. A switch on an Ethernet network works as a multiport repeater as the bits transmitted "start over" at each port on the switch.
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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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Ethernet is an example of what type of technology?
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Baseband
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Explain what a TDR is, and describe how it is used.
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A TDR issues a signal on a cable and then measures the way the signal bounces back (or reflects) to the TDR. Bad connectors, crimps, bends, short circuits, cable mismatches, bad wiring, or other defects modify the signal' s amplitude before it returns to the TDR, thus changing the way it reflects. The TDR then accepts and analyzes the return signal, and based on its condition and the amount of time the signal took to return, determines cable imperfections. In the case of a coaxial cable network, a TDR can indicate whether terminators are properly installed and functional. A TDR can also indicate the distance between nodes and segments.
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Frequencies used to convey speech over telephone lines fall between what two frequencies below?
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3.3 KHz and 300 Hz
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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. There's nothing infinite or continuous about a digital signal because it is inherently either on or off. A pulse of positive voltage represents a 1. A pulse of zero voltage (in other words, the lack of any voltage) represents a 0. The use of 1s and 0s to represent information is characteristic of a binary system. Every pulse in the digital signal is a binary digit, or bit. An analog signal, on the other hand, such as the sound of the human voice or music, has an infinite number of tones and subtle inflections. When digitizing sound, the higher the sampling rate, the more accurate the representation of the analog signals. For example, the sampling rate for digitized voice, such as that used by iPhone' s Siri, is much lower than the sampling rate used for music albums.
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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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Multimode fiber contains a core that is larger than a single mode fiber core.
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True
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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 (Frequency Division Marketing)
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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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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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The most common multiplexing technology used in conjunction with fiber optics is which option below?
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DWDM (Dense Wavelength Division Multiplexing)
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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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Using DWDM, a single fiber can carry between what two numbers of channels?
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80 and 160
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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 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 and 350 MHz
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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 is the minimum category of UTP cable required in order to support Gigabit speeds?
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Cat 5e
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What two items below are commonly expressed as bits transmitted per second?
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Bandwidth and throughput
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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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Which of the following connectors is the most common for multimode fiber?
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MT-RJ
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Which type of multiplexing is defined by wavelength instead of frequency?
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CWDM (Coarse Wavelength Division Multiplexing)
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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
