Chapter 1 Flashcards

1
Q

If the input signal power to a communication system is 1 W and the output power is 1 mW, the system attenuation is:
A. 3 dB
B. 20 dB
C. 30 dB
D. 40 dB
E. 1000 dB

A

C. 30 dB

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2
Q

The signal at the input to a balanced twisted pair cable is 10 mW. The cable is 1000 feet long and has an attenuation of 1 dB per 100 feet. This cable is connected to the input of a receiver. The noise level at the input to the receiver is 1 microwatt. What is the signal-to- noise ratio (SNR) (dB) at the receiver input?
A. 10 dB
B. 30 dB
C. 40 dB
D. 60 dB
E. 100 dB

A

B. 30 dB

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3
Q

A SONET OC-1 channel can carry 672 voice signals and has a data rate of 51.84 Mbps. A
SONET OC-48 channel can carry 32,256 voice channels. What MINIMUM data rate is required for the OC-48 channel?
A. 155 Mbps
B. 622 Mbps
C. 2.5 Gbps
D. 5 Gbps
E. 10 Gbps

A

Answer : C

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4
Q

All of the following are nominal wavelengths for laser light sources EXCEPT:
A. 700 nm
B. 850 nm
C. 1300 nm
D. 1310 nm
E. 1550 nm

A

A. 700 nm

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5
Q

A video camera has a coaxial cable output. The video signal is to be distributed to devices that have balanced twisted pair inputs. The transition between these two different transmission media can be accomplished by using a:
A. Balun
B. Converter
C. Modulator
D. Cross connect
E. Transceiver

A

A. Balun

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6
Q

The public telephone system is an example of a __________ system.
A. Simplex
B. Half-duplex
C. Full-duplex
D. Purely analog
E. Purely digital

A

C. Full-duplex

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7
Q

Wave division multiplexing (WDM) is most similar to:
A. Amplitude modulation
B. Frequency modulation
C. Time division multiplexing
D. Frequency division multiplexing
E. Carrier sense multiple access with collision detection (CSMA/CD)

A

D. Frequency division multiplexing

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8
Q

You must place CAT6 cable above a factory floor with automated welding machines and hammer forges. Of the following, what type of shielding would be most effective?
A. Multi-layer braid
B. Foil and braid
C. Solid metallic conduit
D. Flex metallic conduit
E. Sch. 40 PVC conduit

A

C. Solid metallic conduit

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9
Q

You must place a cable between 2 equipment locations with separate grounds having a potential difference between them of 2.1 V rms. Which one of the following cables should
NOT be used?
A. Multimode
B. Singlemode
C. UTP
D. STP

A

D. STP

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10
Q

Two sinusoidal signals have the same amplitude (A) and the same frequency (f). They differ in phase by 180 degrees. If these two signals are added together, the result is a sinusoidal signal having an amplitude of:
A. Zero
B. 0.707A and a frequency of f
C. A and a frequency of 2f
D. 2A and a frequency of f
E. 2A and a frequency of 2f

A

A. Zero

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11
Q

Composite conductors, although not generally recommended, may be used in special circumstances because they provide all of the following advantages EXCEPT:
A. Have good digital transmission characteristics
B. Lightweight
C. Inexpensive
D. Easy to produce
E. Easily embedded into other materials

A

A. Have good digital transmission characteristics

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12
Q

Which is an advantage of stranded conductors over solid conductors?
A. Less costly
B. Simpler terminations
C. Better high frequency performance
D. More flexible

A

D. More flexible

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13
Q

The conversion of an analog speech signal to a pulse code modulation (PCM) digital signal involves all of the following steps EXCEPT:
A. Low pass filtering
B. Periodic sampling
C. Quantizing
D. Companding
E. Amplitude modulation

A

E. Amplitude modulation

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14
Q

Assume that the optical power transmitted by a 62.5/125 multimode fiber is distributed uniformly across its core. If this fiber is perfectly coupled (i.e., the two fibers are aligned and abutted) to a 50/125 fiber, what is the percent of power that is lost?
A. 0 percent
B. 36 percent
C. 50 percent
D. 80 percent
E. 100 percent

A

B. 36 percent

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15
Q

Which of the following correctly lists the lowest frequency band to the highest frequency band?
A. MF, HF, VHF, UHF
B. UHF, VHF, HF, MF
C. HF, MF, UHF, VHF
D. VHF, UHF, MF, HF
E. HF, MF, UHF, VHF

A

A. MF, HF, VHF, UHF

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16
Q

Time division multiplexing (TDM) systems are designed to transport ________ between end point systems.
A. Only analog signals
B. Only digital signals
C. A mix of both analog and digital signals
D. Both analog and digital signals, but only one type at a time

A

B. Only digital signals

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17
Q

A reasonable approximation for the signal speed in 100 ohm balanced twisted pair cable is __________, where c is the velocity of light in free space.
A. 0.2 c
B. 0.4 c
C. 0.6 c
D. 08 c
E. 0.9 c

A

C. 0.6 c

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18
Q

Which characteristic is an advantage of copper based media over optical fiber cable?
A. Weight
B. Corrosion resistance
C. Ability to handle analog signals
D. Susceptibility to EMI
E. Very high data rates

A

C. Ability to handle analog signals

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19
Q

Which electrical characteristic is displayed with the correct preferred value?
A. Dielectric constant – high value
B. Dielectric strength – high value
C. Dissipation factor – low value
D. Insulation resistance - high value

A

A. Dielectric constant – high value

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20
Q

Optical transmitters are typically one of the following types EXCEPT:
A. Light-emitting diode (LED)
B. Short wavelength laser compact disc (CD)
C. Vertical cavity surface emitting laser (VCEL)
D. Laser diode (LD)
E. Overfilled launch (OFL)

A

E. Overfilled launch (OFL)

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21
Q

You are placing Category 6 unshielded twisted-pair (UTP) in cable tray down a hallway past the elevator mechanical room. What action should you take to avoid effects of electromagnetic interference (EMI)?
A. Provide a minimum separation of 1194 mm (47 in)
B. Provide a minimum separation of 2060 mm (81 in)
C. Require the architect to install metallic foil shielding on the mechanical room walls
D. Provide RMC/IMC (rigid metallic conduit/intermediate metal conduit) through all areas within 4.6 m (15 ft) of the mechanical room

A

A. Provide a minimum separation of 1194 mm (47 in)

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22
Q

You have discovered a common mode current on the metallic cable sheaths of your building riser cables. What is the MOST likely cause for you to investigate?
A. Lack of cable protection
B. Two separate and distinct ground references
C. Improper secondary protection
D. Improper physical protection of cable
E. Improper placement and/or termination of cables

A

B. Two separate and distinct ground references

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23
Q

You are required by architectural design to place UTP cables in the same space as unshielded power lines. How should you proceed with the placement of your cables?
A. Require the architect/electrical engineer to place shielding in the space before your UTP is placed.
B. You should provide a minimum separation of 610 mm (24 in).
C. You should provide a minimum separation of 229 mm (9 in).
D. You should provide a minimum of two 101 mm (4 in) RMC.

A

B. You should provide a minimum separation of 610 mm (24 in).

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24
Q

What is the recommended MINIMUM separation of unshielded twisted-pair (UTP) cables from fluorescent light fixtures?
A. 77 mm (3 in)
B. 30 mm (5.12 in)
C. 203 mm (8 in)
D. 324 mm (12.75 in)
E. 483 mm (19 in)

A

B. 30 mm (5.12 in)

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25
Which of the following is NOT a form of signal coupling between two (2) circuits? A. Conductive B. Inductive C. Reactive D. Capacitive E. Electromagnetic
C. Reactive
26
A common mode (CM) signal can be converted to a differential mode (DM) signal as a result of a(n): A. Unbalanced circuit B. Grounded circuit C. Poorly timed signal D. Improper dielectric material
A. Unbalanced circuit
27
The electromagnetic spectrum of visible light lies in the ___________ frequency range of the spectrum. A. 1 GHz B. 100 GHz C. 10 THz D. 1 PHz E. 100 PHz
D. 1 PHz
28
The potential for ______ occurs when devices or systems share a common electromagnetic environment and their operational frequencies overlap. A. Electromagnetic interference (EMI) B. (EMC) C. Radio frequency interference (RFI) D. Fast transients E. Electrostatic discharge (ESD)
A. Electromagnetic interference (EMI)
29
Which of the following is an undesirable electromagnetic effect on a device(s)? A. (EMC) B. Electromagnetic interference (EMI) C. Radio frequency interference (RFI) D. Fast transients E. Electrostatic discharge (ESD)
B. Electromagnetic interference (EMI)
30
During a site survey you notice that several CRT displays in the vicinity of the engineering copy center have sporadic visual distortion. What is the MOST likely cause? A. Electromagnetic interference (EMI) B. Radio frequency interference (RFI) C. (EMC) D. Fast transients E. Electromagnetic discharge (ESD)
A. Electromagnetic interference (EMI)
31
The ability of a device to withstand electromagnetic disturbances from another device is: A. Electromagnetic interference (EMI) B. Radio Frequency Interference (RFI) C. (EMC) D. Fast transients E. Electrostatic Discharge (ESD)
C. (EMC)
32
Which of the following is NOT a source of electromagnetic interference (EMI)? A. Copiers - B. Transformers - C. Incandescent lights - D. Fluorescent lights - E. Electrical power supply cable
C. Incandescent lights -
33
If looking to specify an optical fiber backbone within a building going 275 m (902 ft) between the equipment room (ER) and the telecommunications room (TR), what type of fiber should be specified to support a 10 GB ethernet application? A. OM1 B. 50 micron multimode C. 50 micron laser optimized multimode D. 62.5 micron multimode
C. 50 micron laser optimized multimode
34
What type of optical fiber is used primarily for outside plant (OSP) applications? A. Tight-buffer B. Loose-tube C. Breakout style D. Duplex zip cord E. Ribbon
B. Loose-tube
35
What is the insertion loss guideline for a multimode mechanical splice? A. 0.05 dB B. 0.1 dB C. 0.3 dB D. 0.5 dB E. 1.0 dB
C. 0.3 dB
36
What is the International Organization for Standardization/International Electrotechnical Commission ISO/IEC class rating for American National Standards Institute/Telecommunication Industry Association (ANSI/TIA) Category 5e cable? A. Class B B. Class C C. Class D D. Class E E. Class F
C. Class D
37
There are three buildings approximately 400 meters apart and the customer wants to use 10 Gig Ethernet. What fiber should be specified for this application? A. 8 - 9 micron singlemode B. 50 micron multimode C. 50 micron laser optimized multimode D. 62.5 micron multimode
A. 8 - 9 micron singlemode
38
Which of the following is true about screened twisted pair cable assemblies? A. The drain wire and screen foil must be bonded at one end only. B. The drain wire and screen foil must be bonded at every connection. C. There is no need to bond the screen foil or drain because it is not important. D. The drain wire and screen foil must be separately bonded at opposite ends.
B. The drain wire and screen foil must be bonded at every connection.
39
Which of the following is NOT a design consideration for broadband video distribution? A. Amplifier link budgets B. Adhering to the 90 meter (295 feet) rule for horizontal distribution C. Amplifier cascade limitations D. Environmental factors E. Drop length
B. Adhering to the 90 meter (295 feet) rule for horizontal distribution
40
You are extending 1000 MHz video service from your existing headend to a new equipment room (ER). Your existing incoming video signal is plus (+) 15 dBmV. You have three two- way splitters with a total of minus (-) 15 dB. You are adding 122 m (400 ft) of series 11 (RG 11) cable with a minus (-) 18 dB with eight single end F-connectors with a total of minus (-) 1.2 dB. From the selections below, what is the MINIMUM gain amplifier required in the headend room? A. Plus (+) 15 dB B. Plus (+) 20 dB C. Plus (+) 25 dB D. Plus (+) 30 dB E. Plus (+) 35 dB
A. Plus (+) 15 dB
41
What is the connector of choice for Series 59, Series 6, and Series 11 applications? A. F-Style B. Bayonet Neill-Conncelman (BNC-Style) C. N-Style D. SMA E. Ultra high frequency (UHF)
A. F-Style
42
You must extend a video systems backbone coax cable that was recently installed. Which of the following coaxial cable types would provide the best performance for both analog and digital video? A. Series 6 B. Series 11 C. RG 16 D. RG 59 E. RG 62
B. Series 11
43
The RJ-45 is now known as the 8P8C style connector, per the Telecommunications Industry Association (TIA) standard. What does the P and C stand for? A. Plug and connector B. Position and connector C. Position and contact D. Plug and contact
C. Position and contact
44
What is the testing frequency of a Category 6/Class E cable? A. 100 MHz B. 200 MHz C. 250 MHz D. 500 MHz E. 600 MHz
C. 250 MHz
45
What type of fiber optic cable is manufactured to protect individual glass strands and is primarily designed for use inside buildings? A. Ribbon B. Tight buffered C. Loose tube D. Air blown
B. Tight buffered
46
The ability of a conductors insulation to transmit an electric field is called: A. Conductivity B. Transmitability C. Permittivity D. Capacitance E. Reactance
C. Permittivity
47
This type of cable is an unbalanced system: A. Unshielded twisted-pair (UTP) B. Shielded twisted-pair (STP) C. Screened twisted-pair (ScTP) D. Coaxial
D. Coaxial
48
What is the frequency rating of an International Organization for Standardization/International Electrotechnical Commission (ISO/IEC) Category 7/Class F cable? A. 100 MHz - B. 250 MHz - C. 500 MHz - D. 600 MHz - E. 1000 MHz -
D. 600 MHz
49
A furniture cluster with 26 requires a MINIMUM of how many multiuser telecommunications outlet assembly (MUTOA)? A. 1 B. 2 C. 3 D. 4 E. 5
C. 3
50
Which of the following is NOT an example of a perimeter pathway? A. Furniture pathways B. Surface raceways C. Multi channel raceways D. Under carpet cabling E. Raceways integrated within walls
A. Furniture pathways
51
On a project with three small conference rooms, a break room, and twelve private offices, what is the MINIMUM number of telecommunications outlet boxes required? A. 16 B. 24 C. 28 D. 40 E. 46
A. 16
52
Which of the following is NOT a type of connector for optical fiber? A. LC B. ST C. SFF D. S/FTP E. SC
D. S/FTP
53
When specifying telecommunications outlet boxes, all of the following should be considered EXCEPT: A. Outlet box shall be a minimum of 100 mm (4 in) x 100 mm (4 in) x 76 mm (3 in) B. Outlet boxes should be installed near an electric outlet at the same height C. Different outlet boxes have different support requirements D. Floor mounted telecom outlet boxes should be coordinated with furniture to minimize the potential trip hazard E. Outlet boxes must be of adequate size so that minimum cable bend radius requirements are not exceeded
A. Outlet box shall be a minimum of 100 mm (4 in) x 100 mm (4 in) x 76 mm (3 in)
54
Assuming the total fill capacity of a pathway is 100 cables (all of the same cable type and size), the MAXIMUM number of cables to be installed during the initial installation, without exceeding the fill ratio is: A. 25 B. 40 C. 50 D. 60
B. 40
55
When installing outlet boxes in ten private offices in an area which may prove to be difficult to install future additional telecommunications outlets, the MINIMUM quantity of outlet boxes that should be installed is: A. 10 B. 20 C. 30 D. Based on the type of cabling specified
B. 20
56
Amplitude
The maximum absolute value reached by a voltage or current waveform. TDMM.* Page G-9
57
Amplitude Modulation (AM)
The modulation in which the amplitude of a carrier wave is varied in accordance with some characteristic of the modulating signal. TDMM.* Page G-9
58
Analog Signal
A signal in the form of a wave that uses continuous variations of a physical characteristic over time (e.g., voltage amplitude, frequency) to transmit information. TDMM.* Page G-9
59
Attenuation
The ratio in decibels of output to input power (or voltage) where the terminations are perfectly matched to the characteristic impedance of the cable. TDMM.* Page 1-53
60
ATM
Asynchronous Transfer Mode A high-speed packet switching protocol that uses fixed-length 53-byte packets organized into cells to carry all types of traffic (e.g., voice, data, still image, audio/video). Fixed-length cells allow cell processing to occur in the hardware, thereby reducing transit delays. ATM is designed to take advantage of high-speed transmission media, such as E3, synchronous optical network (SONET), and T3. TDMM.* Page G-73
61
AWG
American Wire Gauge A system used to specify wire size. The greater the wire diameter, the smaller the AWG value. TDMM.* Page G-8
62
Bandwidth
A range of frequencies available for signaling expressed in hertz (Hz). It is used to denote the potential information handling capacity of the medium, device, or system. TDMM.* Page G-78
63
Broadband Cable
An analog design simultaneously using multiple communication channels separated by guard bands. Commonly used to describe a high-speed digital signal associated with backbone or multiplexed transmissions. TDMM: Page G-23
64
CO
Central Office A common carrier switching center office (also called public exchange) that is conveniently located in areas to serve subscriber homes and businesses. It provides telephony services (lines) that are connected on a local loop. The CO contains switching equipment that can switch calls locally or to long- distance carrier telephone offices. TDMM.* Page G-34
65
Codec
A device that converts speech to a digital signal and its subsequent decoding to speech. TDMM.* Page 1-30
66
Crosstalk
The signal interference between cable pairs, which may be caused by a pair picking up unwanted signals from either adjacent pairs of conductors or nearby cables. TDMM.* Page 1-54
67
Decibel
A logarithmic unit for measuring the relative voltage, current, or power of a signal. One tenth of a bel. TDMM.* Page G-53
68
Delay Skew
The difference in propagation delay between any pairs within the same cable sheath. TDMM.* Page 7-55
69
Digital Signal
Information used by digital devices in the form of a sequence of discrete pulses (e.g., a binary signal with two values used to transmit the two states [0, TDMM: Page G-57
70
Dispersion
1 . The loss of signal resulting from the scattering of light pulses as they are transmitted through a medium. 2. The widening or spreading out of the modes in a light pulse as it progresses along an optical fiber. 3. The characteristics of the sound coverage field of a speaker. TDMM.* Page G-60
71
EMI
Electromagnetic Interference Stray electrical energy radiated from electronic equipment and electronics systems (including cabling). TDMM.* Page 1-10
72
Frequency
The number of cycles that a periodic signal completes in a given time. If the unit of time is one second, the frequency is stated in hertz (Hz). One Hz is equal to one cycle per second. TDMM.* Page G-83
73
IP
Internet Protocol The Open Systems Interconnection (OSI) Reference Model Layer 3 (network layer) protocol most commonly used for internetworking. Required for communications over the internet. TDMM.* Page G-IOO
74
ISDN
Integrated Services Digital Network A digital communications facility designed to provide transparent end-to-end transmission of voice, data, audio/video and still images across the public switched telephone network (PSTN). Different versions and configurations exist regionally and internationally. TDMM.* Page G-98
75
NVP
Nominal Velocity of Propagation The coefficient used to determine the speed of transmission along a cable relative to the speed of light in a vacuum, typically expressed as a percentage. Also called phase velocity and velocity of propagation. TDMM.* Page G-130
76
PCM
Pulse Code Modulation A technique for representing an analog signal as a string of bits. The analog signal is converted to a bit string by periodically sampling the amplitude of the analog signal and representing each sample as a binary number. TDMM.* Page G-155
77
Phase
1 . The relationship in time between two waveforms of the same frequency. 2. The relationship in time between two parameters of a single waveform (e.g., voltage and current). TDMM.* Page G-740
78
PoE
Power over Ethernet A network subsystem that offers the ability for the LAN switching infrastructure to provide power over balanced twisted-pair cabling to an endpoint device (e.g., access point [AP], camera, telephone set). TDMM.* Page G-147
79
Propagation Delay
The time required for a signal to travel from one end of the transmission path to the other end. (T IA) TDMM.* Page G-151
80
QAM
Quadrature Amplitude Modulation A means of encoding digital information over radio, wireline, or optical fiber transmission links. It is a modulation technique that uses variations in signal amplitude and phase, allowing data encoded symbols to be represented as a multitude of 2N states, where each state encodes 2N bits (e. . 2, 4, 8, 16, 32, 64, 128, 256 TDMM.* Page G-155
81
Sinusoid
An oscillating, periodic signal that is completely described by three parameters: amplitude, frequency, and phase. TDMM.* Page 1-18
82
TDM
Time Division Multiplexing A process that combines binary data from several different sources (e.g., voice channels) into a single composite bit stream. TDMM.* Page 1-31
83
What is an electrical conductor?
Any material that can carry an electric charge from one point to another TDMM.* Page 1-2
84
Name the 4 most common electrical conductors for ICT wire and cables.
1 .Copper 2. COPPer-covered steel 3.High-strength copper alloys 4.Aluminum TDMM.* Page 1-2
85
Silver and gold are good conductors, but they are not generally used for ICT wires and cables. Why?
Because of their high cost TDMM.* Page 1-2
86
Which conductor sets the standard for comparing the conductivity of other metals?
Copper TDMM.* Page 1-3, Table 1.1
87
What type of copper is used to set the reference value?
Annealed copper TDMM.* Page 7-3, Table 1.1
88
What type of conductor is typically used for aerial, self-supporting drop wire?
Copper-covered TDMM.* Page 1-3, Table 7.1
89
How does the alloying of pure copper affect its conductivity?
The alloying of pure copper always has an adverse effect on its conductivity. TDMM: Page 1-3, Table 1.1
90
How does the conductivity of aluminum compare the conductivity of copper?
It has about 60 percent conductivity compared to copper. TDMM: Page 7-3, Table 1.1
91
Where are aluminum conductors commonly used?
In electrical utility distribution lines TDMM.* Page 1-3, Table 7.1
92
Which type of solid conductor has the poorest corrosion resistance?
High-strength alloy TDMM.* Page 1-4, Table 7.2
93
What type of solid conductor has the poorest oxidation resistance?
Aluminum TDMM.* Page 1-4, Table 1.2
94
Which type of solid conductor has the best tensile strength?
High-strength alloy TDMM: Page 7-4, Table 1.2
95
Which type of solid conductor has the best ductility
High-strength alloy TDMM: Page 7-4, Table 1.2
96
What is the conductivity for a high-strength alloy conductor?
85% of typical TDMM.* Page 1-4, Table 1.2
97
How are stranded conductors created?
By bundling together a number of small-gauge solid conductors to create a single, larger conductor TDMM.* Page 1-4
98
Name 4 advantages of solid conductors.
1 .Less costly 2.Less complex termination systems 3.Better transmission performance at high frequencies 4.Less resistance TDMM.* Page 1-4
99
Name 3 advantages of stranded conductors.
1 .More flexible 2.Longer flex life 3.Less susceptible to damage during crimp termination processes TDMM.* Page 1-4
100
What is a composite conductor?
A conductor constructed from nontraditional materials (e.g., metallic resins or graphite) TDMM.* Page 1-5
101
Name 5 advantages of composite conductors.
1 .HighIy flexible 2.Lightweight 3.Inexpensive and easy to produce 4.Easily embedded into other materials 5.Low coefficient of expansion TDMM: Page 1-5
102
Name 4 disadvantages of composite conductors.
1 .Poor analog transmission characteristics including high attenuation, especially above 4000 Hz 2.Poor digital transmission characteristics 3.Easily damaged unless encased in a rigid material 4.Inconsistent quality TDMM.* Page 1-5
103
Are cables with composite conductors recommended for use with modern telecommunications networks?
No. Cables with composite conductors are not recommended for use with modern telecommunications networks. If equipment is shipped with this type of cable, discard and replace it with the proper structured cabling patch cord for the project. TDMM.* Page 1-5
104
Why is the AWG system important?
Because it provides a standard reference for comparing various conductor materials TDMM.* Page 1-6
105
What is the purpose of insulation on a cable?
To isolate the flow of current by preventing direct contact between conductors and a conductor and its environment TDMM.* Page 1-6
106
How do dielectrics reduce EM coupling between conductors?
By increasing conductor separation TDMM.* Page 1-6
107
What is the dielectric constant?
The ratio of the capacitance of an insulated conductor to the capacitance of the same conductor uninsulated in the air TDMM.* Page 7-8, Table 1.4
108
What does dielectric strength measure?
The maximum voltage that an insulation can withstand without breakdown TDMM.* Page 1-8, Table 1.4
109
What is dissipation factor?
The relative power loss in the insulation due to molecular excitement and subsequent kinetic and thermal energy losses TDMM: Page 1-8, Table 1.4
110
What is insulation resistance?
The insulation's ability to resist the flow of current through it TDMM.* Page 1-8, Table 1.4
111
How is insulation resistance typically expressed?
In megaohm*km or megaohm*1000 ft TDMM.* Page 1-8, Table 7.4
112
How does cable length affect cable resistance?
As the cable length increases, the insulation resistance becomes smaller. TDMM.* Page 1-8, Table 1.4
113
What is the main reason for twisting conductor pairs?
To minimize crosstalk and noise by decreasing capacitance unbalance and mutual inductance coupling between pairs TDMM.* Page 1-9
114
What does pair-to-pair capacitance unbalance measure?
The electric field coupling between two pairs if a differential voltage is applied on one pair and a differential noise voltage is measured on another pair in close proximity TDMM.* Page 1-9
115
What is mutual inductance?
A measure of the magnetic field coupling between two pairs if a differential current is applied on one pair and a differential noise current is measured on another pair in close proximity TDMM.* Page 1-9
116
How is crosstalk within a multipair cable minimized?
By giving each pair a different twist length within a standard range TDMM.* Page 1-9
117
What type of twist is generally used for voice and low-frequency data cables?
A counterclockwise twist length between -50 mm and -150 mm (1.97 in and 6 in) TDMM.* Page 1-9
118
What is tight twisting?
Creating pair twist lengths that are less than ~12.7 mm (0.50 in) TDMM: Page 1-9
119
Where is tight twisting commonly used?
Within and between computers and other data processing equipment TDMM.* Page 1-9
120
Which cable categories employ tight twisting for optimum transmission performance?
Category 5e, 6, 6A, and higher TDMM.* Page 1-9
121
What term is used to refer to stray electrical radiated from electrical equipment and electronics systems?
Electromagnetic interference (EMI) TDMM.* Page 1-70
122
At what temperature does attenuation increase in balanced twisted-pair cables?
Above 20 ºc (68 ºF) TDMM.* Page 1-10
123
What temperature reference is cited in cabling standards for all twisted- pair cables?
20 ºC +/- 3 ºC (68º F +/- 5.4ºF) TDMM.* Page 1-70
124
What is a cable shield?
A metallic covering or envelope enclosing an insulated conductor, individual group of conductors within a core, and cable core TDMM.* Page 1-73
125
Name 3 potential benefits of using a cable shield if it is properly terminated, bonded, and grounded (earthed).
1 .Reduces the radiated signal from the cable 2.Reduces the effects of electrical hazards 3.Minimizes the effect of external EMI on the conductors within the shielded cable TDMM.* Page 1-13
126
Name 3 factors that can affect a shield's effectiveness.
1 . Type and thickness of the shield material 2.Number and size of openings in the shield 3.Effectiveness of the bonding connection to ground TDMM.* Page 1-13
127
How is shield effectiveness determined?
By measuring the surface transfer impedance TDMM.* Page 1-73
128
What is surface transfer impedance?
The ratio of the conductor-to- shield voltage per unit length to the shield current TDMM.* Page 1-73
129
Why are solid metal tubes inappropriate for most cable applications?
Because of their rigid nature TDMM.* Page 1-14
130
Name the 4 primary criteria for selecting cable shields.
1 .Nature of the signal to be transmitted 2.Magnitude of the EM fields through which the cable will run 3.EMC regulations 4.Physical environment and specific mechanical requirements TDMM.* Page 1-14
131
What type of cable shield has poor tensile strength?
Foil (Foil and Braid) TDMM.* Page 1-15, Table 1.5
132
Which type of cable shield is the least effective for radio frequency?
Flexible conduit TDMM.* Page 1-15, Table 1.5
133
What type of cable shield has a poor fatigue life?
Solid conduit TDMM: Page 1-15, Table 1.5
134
Which cable shields have excellent tensile strength?
1 .SingIe-layer braid 2.Multiple-Iayer braid 3.SoIid conduit TDMM.* Page 1-15, Table 1.5
135
What is permeability?
The property of a magnetic substance that determines the degree in which it modifies the magnetic flux in the region occupied by it in a magnetic field TDMM.* Page 1-15
136
Name 2 reasons for using a drain wire.
1 . To provide an easier means for grounding (earthing) the shield 2.To ensure shield continuity for metallic foil shields TDMM.* Page 1-16
137
How are drain wires typically applied?
Longitudinally next to the metallic part of the shield for the length of the cable TDMM.* Page 1-15
138
What is an analog signal?
A wave that uses continuous variations in time to transmit information (e.g. - voltage, amplitude, or frequency variations) TDMM.* Page 1-17
139
What is the most fundamental concept of an analog signal?
Sinusoid TDMM.* Page 1-17
140
Name the 3 parameters used to describe a sinusoid.
1 .Amplitude 2.Frequency 3. Phase TDMM: Page 1-18
141
What is the standard unit of frequency measurement?
Hertz (Hz) TDMM.* Page 1-18
142
What formula is used to represent the relationship between cycle time and frequency?
f=1/T TDMM.* Page 1-78
143
What is the typical range of frequencies that humans can hear?
20 Hz to 20,000 Hz TDMM.* Page 1-78
144
What range of frequencies is typically used for voice telephone circuits?
300 Hz to 3,400 Hz TDMM.* Page 1-78
145
What is a phase?
A description of the reference time, t = 0 TDMM.* Page 1-19
146
How many degrees are in a cycle?
360 degrees TDMM.* Page 1-79
147
What is a signal's spectrum?
A sum of sinusoidal signals that differ in amplitude, frequency, and phase TDMM.* Page 1-20
148
What is necessary for the received signal to be an exact duplicate of the transmitted signal?
The transmission system must not change the frequency of any signal components, and the relative amplitude and phases of all components must be maintained. TDMM.* Page 1-20
149
What defines the analog signal's bandwidth?
The frequency range of the sinusoidal signals needed to describe an analog signal TDMM.* Page 7-20
150
What is the frequency range of the very low frequency (VLF) band?
3 to 30 kHz TDMM.* Page 1-20, Table 1.7
151
What is the frequency range of the low frequency (LF) band?
30 to 300 kHz TDMM.* Page 1-20, Table 1.7
152
What is the frequency range of the medium frequency (MF) band?
300 to 3000 kHz TDMM.* Page 1-20, Table 1.7
153
What is the frequency range of the high frequency (HF) band?
3 to 30 MHz TDMM.* Page 1-20, Table 1.7
154
What is the frequency range of the very high frequency (VHF) band?
30 to 300 MHz TDMM: Page 1-20, Table 1.7
155
What is the frequency range of the ultra high frequency (UHF) band?
300 to 3000 MHz TDMM.* Page 1-20, Table 1.7
156
What is the frequency range of the community antenna TV (CAT V) band?
54 to 1002 MHz TDMM.* Page 1-20, Table 1.7
157
What is the frequency range of the super high frequency (SHF) band?
3 to 30 GHz TDMM: Page 1-20, Table 1.7
158
What is the frequency range of the extremely high frequency (EHF) band?
30 to 300 GHz TDMM.* Page 1-20, Table 1.7
159
What unit of measure is often used to express the strength of a signal?
Decibel (dB) TDMM.* Page 1-21
160
What dB change occurs when the power is doubled?
+3 dB TDMM.* Page 1-21
161
What dB change occurs when the power is reduced by half?
-3 dB TDMM: Page 1-21
162
True or False Decibel levels are used to express power ratios of all types of analog and digital signals, regardless of the medium.
True. Decibel levels are used to express power ratios of all types of analog and digital signals, regardless of the medium. TDMM.* Page 1-21
163
In telephony, which delays are perceptible?
Delays greater than 50 ms if they are of sufficient strength TDMM.* Page 1-22
164
Name the 3 basic components of a telecommunications transmission system.
1 .Source of energy 2.Medium to carry the energy 3.Receiving device TDMM.* Page 1-23
165
What is the purpose of an analog telephone?
To convert sound waves into electrical analog signals that can be transmitted over much longer distances than the sound waves can travel TDMM: Page 1-23
166
True or False Early telephones were designed to match the frequencies used in human speech, which includes frequencies from 50 Hz to 12 kHz.
False. Although speech may contain frequencies from 50 Hz to 12 kHz, early studies found that good quality speech intelligibility could be obtained if only the frequency range of about 300 Hz to 3400 Hz was actually transmitted. Consequently, this is the frequency band that early telephone circuits were designed to support. TDMM.* Page 1-23
167
What type of device converts electrical energy back into sound energy?
Receiver TDMM.* Page 1-23
168
When does the maximum transmission of electrical power occur in a telephone line?
When a transmitting device and a receiving device have the same load resistance or the same impedance TDMM.* Page 1-24
169
How does impedance differ from resistance?
Both are measured in ohms, but impedance has both a magnitude and a phase component. TDMM.* Page 1-24
170
What is the preferred impedance for private line circuits and trunks?
600 ohms Page 1-24
171
What is the preferred impedance for CO switching system line circuits?
900 ohms Page 1-24
172
When is an echo perceptible during a long- distance phone call?
When part of the transmitted signal is sent or reflected back to the originating end TDMM.* Page 1-24
173
What causes part of a signal to be sent back or reflected to the originating end?
Impedance mismatch between the transmission line and the receiver TDMM.* Page 1-24
174
What principal elements contribute to loss and phase distortion at voice frequencies?
*Conductor resistance *Mutual capacitance of the cable pair TDMM.* Page 1-25
175
How does increasing the frequency affect the speed of transmission through cable pairs?
Increasing the frequency increases the speed of transmission. TDMM.* Page 1-25
176
True or False Increasing the frequency to increase the speed of transmission does not noticeably affect speech intelligibility.
True. Increasing the frequency to increase the speed of transmission does not noticeably affect speech intelligibility, but it can have a great effect on data transmission. TDMM.* Page 1-25
177
What is the purpose of placing load coils along a cable?
To improve speech transmission quality TDMM.* Page 1-25
178
How do load coils improve the quality of speech transmission?
*By compensating for the capacitance of a cable pair *By reducing the capacitive current loading in the range of audio frequencies TDMM.* Page 1-25
179
What is the most common distance between loading points for D loading?
~1.37 km (4495 ft) TDMM.* Page 1-25
180
What is the most common distance between loading points for H loading?
~1.83 km (6004 ft) TDMM: Page 1-25
181
What types of signals are blocked by loading coils?
Analog high fidelity and digital signals TDMM.* Page 1-25
182
How do loading coils affect data transmission?
Load coils adversely affect data transmission.
183
What determines the upper cutoff frequency of a loading coil?
Loading coil spacing determines the upper cutoff frequency. TDMM.* Page 1-25
184
Name 3 common interface options for IP telephony.
1 .IP telephone 2.Computer with IP telephony software and a microphone/ speaker or USB handset 3.Multifunctional devices with a wireless receiver TDMM.* Page 1-26
185
True or False IP telephony software is only operational when the computer is running.
True. IP telephony software is only operational when the computer is running. TDMM.* Page 1-26
186
Name 3 common implementation options for IP telephony architecture.
1 . Separate lines 2.One line for everything using a dual-port IP telephone or a soft telephone 3.Wireless connection using APs to connect the IP telephone TDMM.* Page 1-26
187
Although using a dual-port telephone or softphone may sound like an attractive option, what are the possible drawbacks?
A single cable carrying all information reduces flexibility and redundancy. TDMM.* Page 1-26
188
How many telecommunications outlets or connectors are recommended for each individual work area?
2 TDMM: Page 1-26
189
True or False Both horizontal cables at the work area location should be considered cables that support data applications.
True. While one cable may be associated with voice and the other with data, both should be considered cables that support data applications. TDMM.* Page 1-26
190
What is used to provide uninterrupted power to the telephone set?
Power over Ethernet (POE) TDMM.* Page 1-28
191
What is the most significant property of a digital signal?
The most significant property of a digital signal is that at any time it can take on only a value from a discrete set of values. TDMM.* Page 1-29
192
What 3 steps are used to convert an analog signal to a digital signal?
1 .Filtering 2.SampIing 3.Quantizing/companding TDMM.* Page 1-29
193
Why is the analog filtered before it is sampled?
To limit its frequency content TDMM.* Page 1-29
194
What sampling rate is used to faithfully reproduce the analog signal during the conversion process?
A rate that is at least twice the highest frequency component of the analog signal TDMM.* Page 1-29
195
What is quantizing?
Assigning each sampled value a discrete level that approximates the analog signal at the sampling instant TDMM.* Page 1-30
196
What is companding?
Non-uniform mapping between the analog sampled value to an assigned digital level TDMM.* Page 1-30
197
Name the 2 forms of companding that are in current use.
1 .A-Law 2.Mu-Law TDMM.* Page 1-30
198
What type of companding is used in the United States, Canada, and Japan?
Mu-Law TDMM.* Page 1-30
199
What type of companding is used in the Europe?
A-Law TDMM.* Page 1-30
200
What term is used to describe the three-step process for converting an analog signal into a digital signal?
Pulse code modulation (PCM) TDMM.* Page 1-30
201
What is used to encode speech signals at data rates lower than 64 kb/s?
Data signal processing TDMM.* Page 1-30
202
What data rates can be used by ADPCM?
40, 32, 24, and 16 kb/s TDMM.* Page 1-30
203
What device is used to convert speech to a digital signal and its subsequent decoding to speech?
Codec TDMM.* Page 1-30
204
At what rates can vocoders transmit speech?
8 to 2.4 kbs TDMM.* Page 1-30
205
What do lower bit rates typically imply about a signal's quality?
That the signal quality is degraded TDMM.* Page 1-30
206
What process involves combining binary data from several different sources into a single composite bit stream?
Time division multiplexing (TDM) TDMM.* Page 1-31
207
What is the purpose of TDM?
To increase the information- carrying capacity of the digital telecommunications channel TDMM.* Page 1-31
208
How is TDM accomplished?
By predetermined (deterministic) interleaving of samples from different voice channels along with one or more bits for control purposes to make up a frame TDMM.* Page 1-31
209
What is the most popular form of TDM?
Statistical TDM TDMM.* 1-31
210
In the DSI format, the digital data from — speech channels is combined for transmission over a single transmission channel.
In the DSI format, the digital data from 24 speech channels is combined for transmission over a single transmission channel. TDMM.* Page 1-31
211
What is the data rate for the DSI format?
1.544 Mb/s TDMM.* Page 1-32
212
Describe the CEPT PCM-30 format.
In the CEPT PCM-30 format, the digital data from 30 speech channels is combined for transmission over a single transmission channel. TDMM.* Page 1-32
213
What is the data rate for the CEPT PCM-30 format?
2.048 Mb/s TDMM.* Page 1-32
214
What term is used to describe the process of reconstituting the individual channels from the composite signal?
Demultiplexing TDMM.* Page 1-32
215
What is a channel bank?
Multiplexing and demultiplexing equipment TDMM.* Page 1-32
216
What stages of multiplexing contain A/D conversion?
Only the first order multiplexing stage (T1 and E1) TDMM.* Page 1-32 1
217
In the United States, how many Tl frames are needed to create a superframe?
12 TDMM.* Page 1-33
218
In Europe, how many E1 frames are needed to create a multiframe?
16 TDMM.* Page 1-33
219
What is the basic unit of digital data?
Bit TDMM.* Page 1-33
220
True or False A sequence of binary pulses consisting of of Is and Os is the optimum format for transmitting digital data over balanced- twisted pair cables.
False. A sequence of binary pulses consisting of ones and zeros is not the optimum format for transmitting digital data over balanced twisted-pair cables. TDMM.* Page 1-33
221
What is the final step in the encoding process?
The modification of the shape and pattern of pulses to achieve more efficient transmission TDMM.* Page 1-33
222
What is the line-encoding technique designed to do?
*Eliminate the dc component *Improve timing recovery TDMM.* Page 1-33
223
What encoding technique is used for Tl carriers?
Bipolar alternate mark inversion (AMI) TDMM.* Page 1-33
224
What type of encoding allows signal transition to occur in the middle of every bit interval?
Manchester encoding TDMM.* Page 1-33
225
What term is used to describe the rate at which a signal can change states?
Baud TDMM.* Page 1-34
226
What transmission method is used for ISDN (basic rate)?
2BIQ TDMM.* Page 1-35, Table 1.10
227
What transmission method is used for ISDN (primary rate)?
Bipolar TDMM: Page 1-35, Table 1.10
228
What transmission method is used for HDSL?
2BIQ TDMM: Page 1-35, Table 1.10
229
What transmission method is used for 10 BASE-T?
Manchester TDMM: Page 1-35, Table 1.10
230
What is the encoding rate for ISDN (basic rate)?
160 kb/s TDMM.* Page 1-35, Table 1.10
231
What is the encoding rate for ISDN (primary rate)?
1.544 Mb/s TDMM.* Page 1-35, Table 1.10
232
What is the encoding rate for HDSL?
2 x 784 kb/s TDMM.* Page 1-35, Table 1.10
233
What is the encoding rate for 10BASE-T?
10 Mb/s TDMM.* Page 1-35, Table 1.10
234
What is a QAM signal?
A signal composed of two sinusoidal carriers, each having the same frequency but differing in phase by one quarter of a cycle TDMM.* Page 1-37
235
Which QAM sinusoid is the equivalent of a sine wave?
I signal TDMM.* Page 1-37
236
Which QAM sinusoid is the equivalent of a cosine wave?
Q signal TDMM.* Page 1-37
237
What type of modulation does DMT use?
Multicarrier modulation TDMM.* Page 1-37
238
How can data rates be adjusted with DMT?
By increasing the number of sub-bands and by varying the number of bits carried in each sub-band TDMM.* Page 1-37
239
Which line application uses 8B/1Q4 PAM 5 encoding?
1000BASE4 TDMM.* Page 1-37
240
Name 3 types of transmission circuits.
1 .Simplex 2.Half-dupIex 3.FuIl-duplex TDMM.* Page 1-39
241
What is simplex transmission?
The transmission of signals in one direction only TDMM.* Page 1-39
242
What is half-duplex transmission?
The transmission of signals in in either direction, but in one direction at a time TDMM.* Page 7-39
243
What is full-duplex transmission?
The transmission of signals in both directions at the same time TDMM.* Page 1-39
244
Why is asynchronous transmission a popular method of telecommunications among microcomputer users?
Because of a common standardized interface and protocol between machines TDMM.* Page 1-40
245
Why is asynchronous transmission less efficient than synchronous transmission?
Because it requires the addition of some combination of start and stop bits to the data stream TDMM.* Page 1-40
246
How is synchronous transmission performed?
By synchronizing the data bits in phase or in unison with equally spaced clock signals or pulses TDMM.* Page 1-40
247
What is used to prevent confusion of the characters in the data stream?
Clocking pulses TDMM.* Page 1-40
248
Who are the intended users of basic rate ISDN?
Residential and small business users TDMM.* Page 7-41
249
What is the total information capacity of basic rate ISDN?
144 kb/s (line rate = 160 kb/s) TDMM.* Page 7-41
250
Who are the intended users of primary rate ISDN North America?
Large business users TDMM.* Page 7-47
251
What is the total information capacity of primary rate ISDN North America?
1.536 Mb/s (line rate = 1.544 Mb/s) TDMM.* Page 7-47
252
Delay Skew
The difference in propagation delay between any pairs within the same cable sheath. TDMM.* Page 7-55
253
What is the total information capacity of primary rate ISDN Europe?
1.92 Mb/s (line rate = 2.048 Mb/s) TDMM.* Page 1-41
254
Dispersion
1. The loss of signal resulting from the scattering of light pulses as they are transmitted through a medium. 2. The widening or spreading out of the modes in a light pulse as it progresses along an optical fiber. 3. The characteristics of the sound coverage field of a speaker. TDMM.* Page G-60
255
HDSL requires no repeaters on lines less than ________ for 24 AWG.
HDSL requires no repeaters on lines less than 3600 m (11,811 ft) for 24 AWG. TDMM.* Page 1-42
256
What has effectively replaced HDSL?
SDSL and other xDSL technologies
257
what is SDSL?
A single-pair version of HDSL, transmitting up to DS1 rate signals over a single balanced twisted-pair TDMM.* Page 1-42
258
What is distance limitation for SDSL?
-3000 m (9842 ft) TDMM.* Page 1-42
259
What does asymmetric describe about ASDL technologies?
That they allow more bandwidth downstream (server to client) than they do upstream (client to server) TDMM.* Page 1-43
260
What down-to-upstream ratio is required for good Internet performance?
At least 10:1 TDMM.* Page 1-43
261
What do ADSL modems use to reduce errors caused by impulse noise?
Forward error correction (FEC) TDMM.* Page 1-44
262
What does RADSL allow the access provider (AP) to adjust?
The bandwidth of the DSL link to fit the need of the application and to account for the length and quality of the line TDMM.* Page 1-44
263
How does RADSL increase the percentage of users served by DSL services?
By extending the possible distance from the subscriber to the AP facility TDMM.* Page 7-44
264
What are the target ranges of VDSL downstream rates?
*12.96 to 13.8 Mb/s *25.92 to 27.6 Mb/s *51.84 to 55.2 Mb/s TDMM.* Page 1-45, Table 1-44
265
What are the general ranges of VDSL upstream rates?
*1.6 to 2.3 Mb/s *19.2 Mb/s * Equal to downstream TDMM.* Page 1-45
266
How much delay is introduced by interleaving?
In the order of 40 times the maximum length correctable impulse TDMM.* Page 1-45
267
What is a baseband analog video signal?
A baseband video signal contains all the necessary information to reproduce a picture, but it does not modulate an RF carrier. TDMM.* Page 1-46
268
Name 2 types of baseband signaling.
1 .Composite 2.Component TDMM.* Page 7-46
269
What information is contained in a composite format analog signal?
All the components necessary to construct a monochrome or color picture but no audio information TDMM.* Page 1-46
270
What colors are used to create a color video picture?
Red, green, blue (RGB) TDMM.* Page 7-47
271
How does a component video keep the three-color components of an image separate?
With three cables TDMM.* Page 1-47
272
Why is the RGB signal separated from the luminance signal in a component video?
To minimize crosstalk and permit higher resolution TDMM.* Page 1-47
273
How is RGB signaling typically used?
For high-end graphic workstations where the need for higher-quality imaging is required TDMM.* Page 7-47
274
What does an RF carrier represent?
TV channel TDMM.* Page 1-47
275
Which categories of balanced twisted-pair cabling support baseband composite signaling?
Category 3/class C or higher (for a minimum of zl 00 m [328 ft]) TDMM: Page 1-47
276
Which categories of balanced twisted-pair cabling support RGB component signaling?
Category 3/class C or higher (for a minimum of ~100 m [328 ft] using passive media adapters) TDMM.* Page 1-47
277
Which categories of balanced twisted-pair cabling support broadband analog CATV signaling?
Category 5e/class D or higher TDMM.* Page 7-47
278
What are the components of an idealized transmission line?
Two conductors separated by a dielectric material uniformly spaced over the line's length TDMM.* Page 1-48
279
What was the basis of the earliest functional model of a transmission line?
Resistive loss TDMM.* Page 1-48
280
How can a transmission line be represented?
By an electrical circuit containing only passive components that are arranged in a ladder network TDMM.* Page 7-51
281
Name the 4 primary transmission line parameters.
1 .Series resistance 2.Series inductance 3.Mutual capacitance 4.Mutual conductance TDMM.* Page 7-51
282
What is series resistance?
The loop resistance of a pair of conductors for an incremental length TDMM.* Page 1-51
283
What unit of measure is used to express series resistance?
Ohms TDMM.* Page 1-51
284
What is series inductance?
The loop inductance of a pair of conductors for an incremental length TDMM.* Page 1-51
285
What unit of measure is used to express series inductance?
Henries (H) TDMM.* Page 1-51
286
What is mutual capacitance?
The capacitance between a pair of conductors for an incremental length TDMM.* Page 1-51
287
What unit of measure is used to express mutual inductance?
Henries (H) TDMM: Page 1-51
288
How can the secondary parameters of a transmission line be determined?
Calculated from the primary parameters. Obtained by direct measurement. TDMM.* Page 1-51
289
What unit of measure is used to express mutual conductance?
Siemens (S) TDMM.* Page 7-51
290
What forms the foundation of EM wave theory?
Maxwell's equations TDMM.* Page 1-52
291
How can the secondary parameters of a transmission line be determined?
*By calculating the primary parameters *By direct measurement TDMM.* Page 1-52
292
When is maximum power transferred from the source to the load?
When the source impedance (Zs) and the terminating impedance (Zt) are equal to the complex conjugate of the transmission line characteristic impedance (Zo) TDMM.* Page 7-53
293
What term refers to the ratio of output to input power (or voltage) where the terminations are perfectly matched?
Attenuation TDMM.* Page 1-53
294
What term describes signal interference between cable pairs?
Crosstalk TDMM.* Page 1-54
295
How is NVP for balanced twisted-pair cables expressed?
As a percentage of the speed Of light TDMM.* Page 1-54
296
What is the range of typical NVP values for 100-ohm balanced twisted-pair cables?
.56c to .74c TDMM.* Page 1-54
297
What term is used to describe the difference in propagation delay between any pairs within the same cable sheath?
Delay skew TDMM.* Page 7-55
298
What term describes the ratio between the transmitted power and the reflected power?
Return loss TDMM.* Page 1-55
299
What is signal-to-noise ratio (SNR)?
The ratio between the level Of the received signal at the receiver-end and the level Of the transmitted signal TDMM.* Page 1-56
300
How is attenuation-to-crosstalk ratio (ACR) obtained?
By subtracting the attenuation (dB) from near-end crosstalk (NEXT) (dB) TDMM.* Page 1-56
301
How is ACR normally stated?
At a given frequency TDMM.* Page 1-56
302
What is power sum attenuation-to-crosstalk ratio (PSACR)?
A ratio in decibels determined by subtracting the attenuation from PSNEXT loss between cables or channels in close proximity TDMM.* Page 1-56
303
What is power sum attenuation-to-alien- crosstalk ratio at the near end (PSAACRN)?
A ratio in decibels determined by subtracting the attenuation from the PSANEXT loss between cables or channels in close proximity TDMM.* Page 1-56
304
What is power sum attenuation-to-alien- crosstalk ratio at the far end (PSAACRF)?
A ratio in decibels determined by subtracting the attenuation from the PSAFEXT loss between cables or channels in close proximity TDMM.* Page 1-56
305
How do the cabling standards define a channel?
All cables, cords, and connectors from an equipment connection at one end to the equipment connection at the other end TDMM.* Page 7-57
306
What is the nominal characteristic impedance of balanced twisted-pair cables?
100 ohms at 100 MHz TDMM.* Page 1-57
307
Name the 3 most important parameters that affect the performance of balanced twisted-pair cable in network cabling.
1 . Insertion loss 2. PSNEXT loss 3. Return loss TDMM: Page 1-59
308
What is channel insertion loss?
The sum of the attenuation of the various components in the test channel, plus all the mismatch losses at cable and connector interfaces, and the increase in attenuation adjusted for temperature TDMM.* Page 7-59
309
What is NEXT loss in a channel?
The vector sum of crosstalk induced in the cable, connectors, and patch cords TDMM.* Page 1-59
310
What is power sum equal level far-end crosstalk (PSELFEXT)?
A computation of the unwanted signal coupling from multiple transmitters at the near end into a pair measured at the far end TDMM.* Page 1-59
311
What determines the available channel bandwidth for a specified channel?
The range of frequencies that can be successfully transmitted for a given distance TDMM.* Page 1-60
312
What is the dominant noise source for most LAN systems today?
NEXT interference between all transmit pairs and receive pairs TDMM.* Page 1-60
313
How much horizontal cabling may be used in a permanent link?
Up to -90 m (295 ft) TDMM.* Page 1-62
314
True or False The transmission categories of all components used in the same cabling system must be matched.
True. The transmission categories of all components used in the same cabling system must be matched to provide a consistently high level of reliability and transmission performance. TDMM.* Page 1-63
315
What category/class of balanced twisted-pair cable provides the minimum acceptable performance level for network cabling?
Category 3/class C TDMM.* Page 1-64
316
What category/class of balanced twisted-pair cable is recommended as the minimum by most standards?
Category 5e/class D TDMM.* Page 7-64
317
What category/class of balanced twisted-pair cable represents BICSI best practices for network cabling?
Category 6/class E TDMM: Page 1-64
318
What frequency is supported by Category 3/class C cable?
16 MHz TDMM: Page 1-64, Table 1.15
319
What frequency is supported by Category 5/class D cable?
100 MHz TDMM.* Page 7-64, Table 1.75
320
What frequency is supported by Category 6/class E cable?
250 MHz TDMM.* Page 7-64, Table 1.75
321
How many 10BASE-T systems having Cat 3 transmission characteristics can share a binder group ?
No more than 12 TDMM.* Page 1-72
322
Name 3 advantages of media conversion to balanced twisted-pair.
1. lt can be a cost-effective solution. 2. Moves can be simpler to implement. 3. Less space in risers or conduits is required. TDMM.* Page 1-73
323
Name the 3 main categories of terminal interfaces.
1. Impedance-matching devices 2. Signal converters 3. Media filters TDMM.* Page 7-73
324
How are baluns used?
To adapt the balanced impedance of twisted-pairs to the unbalanced impedance of coaxial cables TDMM.* Page 1-73
325
Where are baluns required?
Wherever a transition is made from twisted-pair to coaxial or from coaxial to twisted-pair TDMM.* Page 1-73
326
What is a signal converter?
An electronic device that receives one type of signal and outputs another type of signal TDMM.* Page 1-73
327
Name 2 advantages of signal converters.
1 .Decrease the risk of transmission and EMI problems. 2. Extend the unbalanced signal reach of a DTE. TDMM.* Page 1-73
328
What is the purpose of a media filter?
To eliminate unwanted frequencies affecting link performance that could radiate from the balanced twisted-pair cable TDMM.* Page 7-74
329
What is a transceiver?
A radio frequency device capable of sending and receiving radio frequencies TDMM.* Page 1-74
330
Name 4 benefits of combining power and data onto a single cable.
1. Eliminating the need to provide AC electrical outlets at the same location 2. Faster installation times 3. Detecting loss of power to a device 4. In the event of a power failure, the network backup power system can service POE devices and systems, as well as other network devices. TDMM.* Page 1-75
331
What is the maximum power output for Type 1 POE?
15.4 W from the PSE with up to 12.95 W delivered to the PD TDMM: Page 1-76
332
What is the maximum power output for Type 2 POE?
30 W from the PSE with up to 25.5 W delivered to the PD TDMM.* Page 1-76
333
What is the maximum power output for Type 3 POE?
60 W from the PSE with up to 51 W delivered to the PD TDMM.* Page 7-75
334
What is the maximum power output for Type 4 POE?
90 W from the PSE with up to 73 W delivered to the PD TDMM.* Page 1-75
335
What is link layer discovery protocol (LLDP)?
Type 3 or 4 PSE power classification information exchanged during initial negotiation TDMM.* Page 1-76
336
Name 3 practical power sourcing equipment (PSE) options for POE.
1 .Endspan devices 2.Midspan devices 3.LocaI power sources TDMM.* Page 1-77
337
Name the 3 elements of a simple model telecommunications system.
1 .Transmitter 2.Receiver 3.Medium TDMM.* Page 1-78
338
What is the purpose of an optical transmitter?
To convert electrical signals to optical signals for transmission over an optical fiber cable TDMM.* Page 1-78
339
What are the 4 nominal wavelengths of optical fiber transmitters?
1.850 nm 2.1300 nm 3.1310 nm 4.1550 nm TDMM.* Page 1-78
340
What term refers to the range of wavelengths over which the total power emitted by a transmitter is distributed?
Spectral width TDMM.* Page 7-80
341
What unit of measure is typically used to specify spectral width?
Nanometer (nm) TDMM.* Page 7-80
342
How do wide spectral widths affect the dispersion of light pulses?
Wide spectral widths lead to increased dispersion of light pulses as the light pulses propagate through an optical fiber. TDMM.* Page 1-81
343
What is the average power of a transmitter?
The mean level of power output of a given light source during modulation TDMM.* Page 1-81
344
What is the modulation frequency of a transmitter?
The rate at which the transmission changes in intensity TDMM.* Page 1-83
345
Name 3 major types of transmitter light sources.
1 .LEDs 2.VCSELs 3.LDs TDMM.* Page 1-83
346
What center wavelength ranges are typical for LEDs?
800 to 900 nm 1250 to 1350 nm TDMM. Page 1-83, Table 1.20
347
What is the modulation frequency of most LEDs?
Under 200 MHz TDMM.* Page 1-83, Table 1.20
348
What is the average launched optical power level Of LEDS?
-10 to -30 dBm into multimode fiber TDMM.* Page 1-83, Table 1.20
349
What is the center wavelength for short wavelength lasers?
780 nm TDMM.* Page 1-84, Table 1.21
350
How does the modulation frequency of short wavelength lasers compare to that of LEDs?
It is higher than LEDs (can exceed 1 GHz). TDMM.* Page 1-84, Table 1.21
351
What is the average launched optical power level of short wavelength lasers?
+1 to -8 decibels per mw (dBm) TDMM.* Page 7-84, Table 1.21
352
What are the center wavelengths used for VCSELs?
*850 nm *1300 nm TDMM.* Page 7-85, Table 1.22
353
How does the modulation frequency for VCSELs compare to that of LEDs?
It is much higher than that of LEDs, allowing up to 56 GHz. TDMM.* Page 1-85, Table 1.22
354
What is the average launched power level of VCSELs?
-1 to -8 decibels per milliwatt into multimode fiber TDMM.* Page 1-85, Table 1.22
355
What is the most predominate center wavelength for laser diodes (LDs)?
1310 nm TDMM.* Page 1-86, Table 1.23
356
How does the spectral width for LDs compare to that of LEDs?
Narrow in comparison TDMM.* Page 7-86, Table 1.23
357
Where are typical LD sources used?
Almost exclusively in singlemode optical fiber links TDMM.* Page 1-86, Table 1.23
358
What is the average launched optical power level of LDs?
Common values of +4 to -9 power level decibels per milliwatt into singlemode optical fibers TDMM.* Page 1-86, Table 1.23
359
Which type of transmitter is the most expensive: LED, VCSEL, or LD?
LD TDMM.* Page 1-87, Table 1.24
360
What is the primary type of optical fiber used with LD transmitters?
Singlemode TDMM.* Page 1-87, Table 1.24
361
Name the 3 characteristic parameters of optical fiber receivers.
1. Sensitivity 2. Bit error rate (BER) 3. Dynamic range TDMM.* Page 1-88
362
Define sensitivity in terms of optical fiber receivers.
The minimum power level an incoming signal must have to achieve an acceptable level of performance TDMM.* Page 1-88
363
What is bit error rate (BER)?
The fractional number of errors allowed to occur between the transmitter and receiver TDMM.* Page 7-88
364
What happens to the BER if the power of the incoming signal falls below the receiver sensitivity?
The number of bit errors will increase beyond the maximum BER specified for the receiver. TDMM.* Page 1-88
365
What is dynamic range?
The range of power that a receiver can process at a specified bit error rate (BER) TDMM.* Page 1-88
366
Name 3 key factors that are used to determine which optical fiber to use in a given application.
1. Active equipment 2. Distance 3. Bandwidth (data rate) TDMM.* Page 1-89
367
Which classes of multimode cable are recognized for use in new installations?
OM3 OM4 OM5 TDMM.* Page 1-90
368
Name the 2 essential determinants of the end-to-end bandwidth for an optical fiber system.
1. Transmitter 2. Optical fiber TDMM.* Page 1-91
369
What is rise time?
The time it takes transmitters to change from a low-power state (logical 0) to a high-power state (logical 1) TDMM.* Page 1-92
370
How does dispersion affect a light pulse?
It causes the light pulse to broaden in duration as it travels through the optical fiber. TDMM.* Page 1-94
371
What is often used in place of bandwidth to define system capacity in singlemode systems?
Maximum pulse distortion TDMM.* Page 7-94
372
Name the 3 effects that are combined to calculate and predict the bandwidth requirements for a multimode system.
1. Transmitter rise time 2. Optical fiber modal dispersion 3. Chromatic dispersion TDMM.* Page 1-94
373
What type of dispersion occurs when the wider range of wavelengths in each pulse travels at a wider range of individual speeds?
Chromatic dispersion TDMM.* Page 1-95
374
What is modal dispersion?
An event that occurs when a pulse of light, which consists of hundreds of modes in a multimode optical fiber, broadens in time as it travels through the optical fiber TDMM.* Page 1-95
375
What are the 2 major classifications of optical fiber cable?
1 . Singlemode 2. Multimode TDMM: Page 1-98
376
What are the 2 popular sizes of multimode optical fiber cables?
1.62.5/125 2.50/125 TDMM.* Page 1-99, Table 1.27
377
What are the most common wavelength windows for optical fiber cables?
* 850 nm * 1300 nm * 1550 nm TDMM.* Page 1-701
378
What is the characteristic core diameter for singlemode optical fiber?
Between 8 and 9 um TDMM.* Page 1-102, Table 1.30
379
What is the diameter of the cladding on a singlemode optical fiber cable?
125 pm TDMM.* Page 7-102, Table 1.30
380
What is bandwidth for singlemode optical fiber?
Greater than 20 GHz TDMM.* Page 71-102, Table 1.30
381
What are the operating wavelengths for singlemode optical fiber?
*1310 nm *1550 nm TDMM.* Page 1-102, Table 1.30
382
What establishes the maximum supportable distance for optical fiber cables?
Application standards TDMM.* Page 1-103
383
What establishes maximum channel attenuation?
The difference between the minimum transmitter output power coupled into the optical fiber and the receiver sensitivity, less any power penalties established TDMM.* Page 1-103
384
What is the maximum attenuation value for 50/125 pm multimode cable at 850 nm?
3.5 dB/km TDMM.* Page 1-104, Table 1.31
385
What is the maximum attenuation value for 62.5/125 pm multimode cable at 1300 nm?
1.5 dB/km TDMM.* Page 1-104, Table 1.31
386
What is the maximum attenuation value for singlemode inside plant cable at 1310 nm?
1.0 dB/km TDMM.* Page 7-704, Table 1.31
387
What is the maximum attenuation value for singlemode outside plant cable at 1550 nm?
0.4 dB/km TDMM.* Page 1-104, Table 1.31
388
How is optical fiber cable bandwidth validated?
Through the manufacturer's specification and quality checking of the product specification sheets with the installed components TDMM.* Page 1-107
389
What determines the maximum permissible end- to-end system attenuation in a given link?
The average transmitter power and the receiver sensitivity TDMM.* Page 1-107
390
What connector loss value should be used for 0 to 4 connector pairs?
The maximum value TDMM.* Page 1-113
391
What connector loss value should be used for 5 or more connector pairs?
The typical value TDMM.* Page 1-113
392
What is the recommended maximum loss value for optical fiber cable connectors?
0.75 dB TDMM.* Page 1-173
393
What is the average splice loss for a fusion splice in multimode cabling?
0.05 dB TDMM.* Page 1-113, Table 1.36
394
What is the maximum splice loss for mechanical and fusion splices in multimode cabling?
0.3 dB TDMM.* Page 1-113, Table 1.36
395
How is the minimum required system loss calculated?
By subtracting the receiver's dynamic range from the system gain TDMM.* Page 1-114
396
What device can be used to add additional loss to an optical fiber system?
Attenuator TDMM.* Page 1-115
397
Name the 2 standards that have been established for optical fiber carrier transmissions.
1 .Synchronous Optical Network (SONET)-North America 2.Synchronous Digital Hierarchy (SDH)—lnternational TDMM.* Page 1-716