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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
Q

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

A

C. Reactive

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26
Q

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

A. Unbalanced circuit

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27
Q

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

A

D. 1 PHz

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28
Q

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

A. Electromagnetic interference (EMI)

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29
Q

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)

A

B. Electromagnetic interference (EMI)

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30
Q

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

A. Electromagnetic interference (EMI)

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31
Q

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)

A

C. (EMC)

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32
Q

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

A

C. Incandescent lights -

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33
Q

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

A

C. 50 micron laser optimized multimode

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34
Q

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

A

B. Loose-tube

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35
Q

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

A

C. 0.3 dB

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36
Q

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

A

C. Class D

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37
Q

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

A. 8 - 9 micron singlemode

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38
Q

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.

A

B. The drain wire and screen foil must be bonded at every connection.

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39
Q

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

A

B. Adhering to the 90 meter (295 feet) rule for horizontal distribution

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40
Q

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

A. Plus (+) 15 dB

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41
Q

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

A. F-Style

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42
Q

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

A

B. Series 11

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43
Q

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

A

C. Position and contact

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44
Q

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

A

C. 250 MHz

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45
Q

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

A

B. Tight buffered

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46
Q

The ability of a conductors insulation to transmit an electric field is called:
A. Conductivity
B. Transmitability
C. Permittivity
D. Capacitance
E. Reactance

A

C. Permittivity

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47
Q

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

A

D. Coaxial

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48
Q

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 -

A

D. 600 MHz

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49
Q

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

A

C. 3

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50
Q

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

A. Furniture pathways

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51
Q

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

A. 16

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52
Q

Which of the following is NOT a type of connector for optical fiber?
A. LC
B. ST
C. SFF
D. S/FTP
E. SC

A

D. S/FTP

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53
Q

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

A. Outlet box shall be a minimum of 100 mm (4 in) x 100 mm (4 in) x 76 mm (3 in)

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54
Q

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

A

B. 40

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55
Q

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

A

B. 20

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56
Q

Amplitude

A

The maximum absolute value
reached by a voltage or current
waveform.
TDMM.* Page G-9

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57
Q

Amplitude Modulation (AM)

A

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

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58
Q

Analog Signal

A

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

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59
Q

Attenuation

A

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

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60
Q

ATM

A

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

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61
Q

AWG

A

American Wire Gauge
A system used to specify wire
size. The greater the wire
diameter, the smaller
the AWG value.
TDMM.* Page G-8

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62
Q

Bandwidth

A

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

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63
Q

Broadband Cable

A

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

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64
Q

CO

A

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

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65
Q

Codec

A

A device that converts speech to
a digital signal and its
subsequent decoding to speech.
TDMM.* Page 1-30

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66
Q

Crosstalk

A

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

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67
Q

Decibel

A

A logarithmic unit for measuring the relative voltage, current, or
power of a signal. One tenth of a bel.
TDMM.* Page G-53

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68
Q

Delay Skew

A

The difference in propagation
delay between any pairs within
the same cable sheath.
TDMM.* Page 7-55

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69
Q

Digital Signal

A

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

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70
Q

Dispersion

A

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

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71
Q

EMI

A

Electromagnetic Interference
Stray electrical energy radiated
from electronic equipment
and electronics systems
(including cabling).
TDMM.* Page 1-10

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72
Q

Frequency

A

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

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73
Q

IP

A

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

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74
Q

ISDN

A

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

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75
Q

NVP

A

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

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76
Q

PCM

A

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

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77
Q

Phase

A

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

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78
Q

PoE

A

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

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79
Q

Propagation Delay

A

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

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80
Q

QAM

A

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

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81
Q

Sinusoid

A

An oscillating, periodic signal
that is completely described by
three parameters: amplitude,
frequency, and phase.
TDMM.* Page 1-18

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82
Q

TDM

A

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

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83
Q

What is an electrical
conductor?

A

Any material that can carry an
electric charge from one point
to another
TDMM.* Page 1-2

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84
Q

Name the 4 most common
electrical conductors for
ICT wire and cables.

A

1 .Copper
2. COPPer-covered steel
3.High-strength copper alloys
4.Aluminum
TDMM.* Page 1-2

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85
Q

Silver and gold are good
conductors, but they are
not generally used for ICT
wires and cables. Why?

A

Because of their high cost
TDMM.* Page 1-2

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86
Q

Which conductor sets the
standard for comparing the
conductivity of other
metals?

A

Copper
TDMM.* Page 1-3, Table 1.1

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87
Q

What type of copper is
used to set the reference
value?

A

Annealed copper
TDMM.* Page 7-3, Table 1.1

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88
Q

What type of conductor is
typically used for aerial,
self-supporting drop wire?

A

Copper-covered
TDMM.* Page 1-3, Table 7.1

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89
Q

How does the alloying of
pure copper affect its
conductivity?

A

The alloying of pure copper
always has an adverse effect on
its conductivity.
TDMM: Page 1-3, Table 1.1

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90
Q

How does the conductivity of aluminum compare the conductivity of copper?

A

It has about 60 percent
conductivity compared
to copper.
TDMM: Page 7-3, Table 1.1

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91
Q

Where are aluminum
conductors commonly
used?

A

In electrical utility
distribution lines
TDMM.* Page 1-3, Table 7.1

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92
Q

Which type of solid
conductor has the poorest
corrosion resistance?

A

High-strength alloy
TDMM.* Page 1-4, Table 7.2

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93
Q

What type of solid
conductor has the poorest
oxidation resistance?

A

Aluminum
TDMM.* Page 1-4, Table 1.2

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94
Q

Which type of solid
conductor has the best
tensile strength?

A

High-strength alloy
TDMM: Page 7-4, Table 1.2

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95
Q

Which type of solid
conductor has the
best ductility

A

High-strength alloy
TDMM: Page 7-4, Table 1.2

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96
Q

What is the conductivity for
a high-strength alloy
conductor?

A

85% of typical
TDMM.* Page 1-4, Table 1.2

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97
Q

How are stranded
conductors created?

A

By bundling together a number
of small-gauge solid conductors
to create a single, larger
conductor
TDMM.* Page 1-4

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98
Q

Name 4 advantages of
solid conductors.

A

1 .Less costly
2.Less complex termination
systems
3.Better transmission
performance at high
frequencies
4.Less resistance
TDMM.* Page 1-4

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99
Q

Name 3 advantages of
stranded conductors.

A

1 .More flexible
2.Longer flex life
3.Less susceptible to damage
during crimp termination
processes
TDMM.* Page 1-4

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100
Q

What is a composite
conductor?

A

A conductor constructed from
nontraditional materials (e.g.,
metallic resins or graphite)
TDMM.* Page 1-5

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101
Q

Name 5 advantages of
composite conductors.

A

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

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102
Q

Name 4 disadvantages of
composite conductors.

A

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

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103
Q

Are cables with composite
conductors recommended
for use with modern
telecommunications
networks?

A

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

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104
Q

Why is the AWG
system important?

A

Because it provides a standard
reference for comparing various
conductor materials
TDMM.* Page 1-6

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105
Q

What is the purpose of
insulation on a cable?

A

To isolate the flow of current by
preventing direct contact
between conductors and a
conductor and its environment
TDMM.* Page 1-6

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106
Q

How do dielectrics reduce
EM coupling between
conductors?

A

By increasing conductor
separation
TDMM.* Page 1-6

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107
Q

What is the dielectric
constant?

A

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

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108
Q

What does dielectric
strength measure?

A

The maximum voltage that an
insulation can withstand
without breakdown
TDMM.* Page 1-8, Table 1.4

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109
Q

What is dissipation factor?

A

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

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110
Q

What is insulation
resistance?

A

The insulation’s ability to resist
the flow of current through it
TDMM.* Page 1-8, Table 1.4

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111
Q

How is insulation
resistance typically
expressed?

A

In megaohmkm or
megaohm1000 ft
TDMM.* Page 1-8, Table 7.4

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112
Q

How does cable length
affect cable resistance?

A

As the cable length increases,
the insulation resistance
becomes smaller.
TDMM.* Page 1-8, Table 1.4

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113
Q

What is the main reason for
twisting conductor pairs?

A

To minimize crosstalk and noise
by decreasing capacitance
unbalance and mutual
inductance coupling
between pairs
TDMM.* Page 1-9

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114
Q

What does pair-to-pair
capacitance unbalance
measure?

A

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

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115
Q

What is mutual inductance?

A

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

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116
Q

How is crosstalk within a
multipair cable minimized?

A

By giving each pair a different
twist length within a
standard range
TDMM.* Page 1-9

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117
Q

What type of twist is
generally used for voice
and low-frequency data
cables?

A

A counterclockwise twist length
between -50 mm and -150 mm
(1.97 in and 6 in)
TDMM.* Page 1-9

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118
Q

What is tight twisting?

A

Creating pair twist lengths that
are less than ~12.7 mm (0.50 in)
TDMM: Page 1-9

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119
Q

Where is tight twisting
commonly used?

A

Within and between computers
and other data processing
equipment
TDMM.* Page 1-9

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120
Q

Which cable categories
employ tight twisting for
optimum transmission
performance?

A

Category 5e, 6, 6A, and higher
TDMM.* Page 1-9

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121
Q

What term is used to refer
to stray electrical radiated
from electrical equipment
and electronics systems?

A

Electromagnetic interference
(EMI)
TDMM.* Page 1-70

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122
Q

At what temperature does
attenuation increase in
balanced twisted-pair
cables?

A

Above 20 ºc (68 ºF)
TDMM.* Page 1-10

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123
Q

What temperature
reference is cited in cabling
standards for all twisted-
pair cables?

A

20 ºC +/- 3 ºC (68º F +/- 5.4ºF)
TDMM.* Page 1-70

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124
Q

What is a cable shield?

A

A metallic covering or envelope
enclosing an insulated
conductor, individual group of
conductors within a core, and
cable core
TDMM.* Page 1-73

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125
Q

Name 3 potential benefits
of using a cable shield if it
is properly terminated,
bonded, and grounded
(earthed).

A

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

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126
Q

Name 3 factors that can
affect a shield’s
effectiveness.

A

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

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127
Q

How is shield effectiveness
determined?

A

By measuring the surface
transfer impedance
TDMM.* Page 1-73

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128
Q

What is surface transfer
impedance?

A

The ratio of the conductor-to-
shield voltage per unit length to
the shield current
TDMM.* Page 1-73

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129
Q

Why are solid metal tubes
inappropriate for most
cable applications?

A

Because of their rigid nature
TDMM.* Page 1-14

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130
Q

Name the 4 primary criteria
for selecting cable shields.

A

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

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131
Q

What type of cable shield
has poor tensile strength?

A

Foil (Foil and Braid)
TDMM.* Page 1-15, Table 1.5

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132
Q

Which type of cable shield
is the least effective for
radio frequency?

A

Flexible conduit
TDMM.* Page 1-15, Table 1.5

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133
Q

What type of cable shield
has a poor fatigue life?

A

Solid conduit
TDMM: Page 1-15, Table 1.5

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134
Q

Which cable shields have
excellent tensile strength?

A

1 .SingIe-layer braid
2.Multiple-Iayer braid
3.SoIid conduit
TDMM.* Page 1-15, Table 1.5

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135
Q

What is permeability?

A

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

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136
Q

Name 2 reasons for
using a drain wire.

A

1 . To provide an easier means
for grounding (earthing) the
shield
2.To ensure shield continuity for
metallic foil shields
TDMM.* Page 1-16

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137
Q

How are drain wires
typically applied?

A

Longitudinally next to the
metallic part of the shield for the
length of the cable
TDMM.* Page 1-15

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138
Q

What is an analog signal?

A

A wave that uses continuous
variations in time to transmit
information (e.g. - voltage,
amplitude, or frequency
variations)
TDMM.* Page 1-17

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139
Q

What is the most
fundamental concept of an
analog signal?

A

Sinusoid
TDMM.* Page 1-17

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140
Q

Name the 3 parameters
used to describe a sinusoid.

A

1 .Amplitude
2.Frequency
3. Phase
TDMM: Page 1-18

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141
Q

What is the standard unit of
frequency measurement?

A

Hertz (Hz)
TDMM.* Page 1-18

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142
Q

What formula is used to
represent the relationship
between cycle time and
frequency?

A

f=1/T
TDMM.* Page 1-78

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143
Q

What is the typical range of
frequencies that humans
can hear?

A

20 Hz to 20,000 Hz
TDMM.* Page 1-78

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144
Q

What range of frequencies
is typically used for voice
telephone circuits?

A

300 Hz to 3,400 Hz
TDMM.* Page 1-78

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145
Q

What is a phase?

A

A description of the reference
time, t = 0
TDMM.* Page 1-19

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146
Q

How many degrees
are in a cycle?

A

360 degrees
TDMM.* Page 1-79

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147
Q

What is a signal’s
spectrum?

A

A sum of sinusoidal signals that
differ in amplitude, frequency,
and phase
TDMM.* Page 1-20

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148
Q

What is necessary for the
received signal to be an
exact duplicate of the
transmitted signal?

A

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

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149
Q

What defines the analog
signal’s bandwidth?

A

The frequency range of the
sinusoidal signals needed to
describe an analog signal
TDMM.* Page 7-20

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150
Q

What is the frequency
range of the very low
frequency (VLF) band?

A

3 to 30 kHz
TDMM.* Page 1-20, Table 1.7

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151
Q

What is the frequency
range of the low frequency
(LF) band?

A

30 to 300 kHz
TDMM.* Page 1-20, Table 1.7

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152
Q

What is the frequency
range of the medium
frequency (MF) band?

A

300 to 3000 kHz
TDMM.* Page 1-20, Table 1.7

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153
Q

What is the frequency
range of the high frequency
(HF) band?

A

3 to 30 MHz
TDMM.* Page 1-20, Table 1.7

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154
Q

What is the frequency
range of the very high
frequency (VHF) band?

A

30 to 300 MHz
TDMM: Page 1-20, Table 1.7

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155
Q

What is the frequency
range of the ultra high
frequency (UHF) band?

A

300 to 3000 MHz
TDMM.* Page 1-20, Table 1.7

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156
Q

What is the frequency
range of the community
antenna TV (CAT V) band?

A

54 to 1002 MHz
TDMM.* Page 1-20, Table 1.7

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157
Q

What is the frequency
range of the super high
frequency (SHF) band?

A

3 to 30 GHz
TDMM: Page 1-20, Table 1.7

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158
Q

What is the frequency
range of the extremely high
frequency (EHF) band?

A

30 to 300 GHz
TDMM.* Page 1-20, Table 1.7

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159
Q

What unit of measure is
often used to express the
strength of a signal?

A

Decibel (dB)
TDMM.* Page 1-21

160
Q

What dB change occurs
when the power is
doubled?

A

+3 dB
TDMM.* Page 1-21

161
Q

What dB change occurs
when the power is
reduced by half?

A

-3 dB
TDMM: Page 1-21

162
Q

True or False
Decibel levels are used to
express power ratios of all
types of analog and digital
signals, regardless of the
medium.

A

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
Q

In telephony, which delays
are perceptible?

A

Delays greater than 50 ms if
they are of sufficient strength
TDMM.* Page 1-22

164
Q

Name the 3 basic
components of a
telecommunications
transmission system.

A

1 .Source of energy
2.Medium to carry the energy
3.Receiving device
TDMM.* Page 1-23

165
Q

What is the purpose of an
analog telephone?

A

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
Q

True or False
Early telephones were
designed to match the
frequencies used in human
speech, which includes
frequencies from 50 Hz to
12 kHz.

A

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
Q

What type of device
converts electrical energy
back into sound energy?

A

Receiver
TDMM.* Page 1-23

168
Q

When does the maximum
transmission of electrical
power occur in a
telephone line?

A

When a transmitting device and
a receiving device have the
same load resistance or the
same impedance
TDMM.* Page 1-24

169
Q

How does impedance differ
from resistance?

A

Both are measured in ohms, but
impedance has both a
magnitude and a phase
component.
TDMM.* Page 1-24

170
Q

What is the preferred
impedance for private line
circuits and trunks?

A

600 ohms
Page 1-24

171
Q

What is the preferred
impedance for CO
switching system line
circuits?

A

900 ohms
Page 1-24

172
Q

When is an echo
perceptible during a long-
distance phone call?

A

When part of the transmitted
signal is sent or reflected back
to the originating end
TDMM.* Page 1-24

173
Q

What causes part of a
signal to be sent back or
reflected to the originating
end?

A

Impedance mismatch between
the transmission line and
the receiver
TDMM.* Page 1-24

174
Q

What principal elements
contribute to loss and
phase distortion at voice
frequencies?

A

*Conductor resistance
Mutual capacitance of the
cable pair
TDMM. Page 1-25

175
Q

How does increasing the
frequency affect the speed
of transmission through
cable pairs?

A

Increasing the frequency
increases the speed of
transmission.
TDMM.* Page 1-25

176
Q

True or False
Increasing the frequency to increase the speed of transmission does not noticeably affect speech intelligibility.

A

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
Q

What is the purpose of
placing load coils along
a cable?

A

To improve speech
transmission quality
TDMM.* Page 1-25

178
Q

How do load coils improve
the quality of speech
transmission?

A

*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
Q

What is the most common
distance between loading
points for D loading?

A

~1.37 km (4495 ft)
TDMM.* Page 1-25

180
Q

What is the most common
distance between loading
points for H loading?

A

~1.83 km (6004 ft)
TDMM: Page 1-25

181
Q

What types of signals are
blocked by loading coils?

A

Analog high fidelity and
digital signals
TDMM.* Page 1-25

182
Q

How do loading coils affect
data transmission?

A

Load coils adversely affect
data transmission.

183
Q

What determines the upper
cutoff frequency of a
loading coil?

A

Loading coil spacing determines
the upper cutoff frequency.
TDMM.* Page 1-25

184
Q

Name 3 common interface
options for IP telephony.

A

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
Q

True or False
IP telephony software is
only operational when the
computer is running.

A

True. IP telephony software is
only operational when the
computer is running.
TDMM.* Page 1-26

186
Q

Name 3 common
implementation options for
IP telephony architecture.

A

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
Q

Although using a dual-port
telephone or softphone
may sound like an
attractive option, what are
the possible drawbacks?

A

A single cable carrying all
information reduces flexibility
and redundancy.
TDMM.* Page 1-26

188
Q

How many
telecommunications
outlets or connectors are
recommended for each
individual work area?

A

2
TDMM: Page 1-26

189
Q

True or False
Both horizontal cables at
the work area location
should be considered
cables that support data
applications.

A

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
Q

What is used to provide
uninterrupted power to the
telephone set?

A

Power over Ethernet (POE)
TDMM.* Page 1-28

191
Q

What is the most
significant property of a
digital signal?

A

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
Q

What 3 steps are used to
convert an analog signal to
a digital signal?

A

1 .Filtering
2.SampIing
3.Quantizing/companding
TDMM.* Page 1-29

193
Q

Why is the analog filtered
before it is sampled?

A

To limit its frequency content
TDMM.* Page 1-29

194
Q

What sampling rate is used
to faithfully reproduce the
analog signal during the
conversion process?

A

A rate that is at least twice the
highest frequency component
of the analog signal
TDMM.* Page 1-29

195
Q

What is quantizing?

A

Assigning each sampled value a
discrete level that approximates
the analog signal at the
sampling instant
TDMM.* Page 1-30

196
Q

What is companding?

A

Non-uniform mapping between
the analog sampled value to an
assigned digital level
TDMM.* Page 1-30

197
Q

Name the 2 forms of
companding that are in
current use.

A

1 .A-Law
2.Mu-Law
TDMM.* Page 1-30

198
Q

What type of companding
is used in the United States,
Canada, and Japan?

A

Mu-Law
TDMM.* Page 1-30

199
Q

What type of companding
is used in the Europe?

A

A-Law
TDMM.* Page 1-30

200
Q

What term is used to describe the three-step process for converting an analog signal into a digital signal?

A

Pulse code modulation (PCM)
TDMM.* Page 1-30

201
Q

What is used to encode
speech signals at data
rates lower than 64 kb/s?

A

Data signal processing
TDMM.* Page 1-30

202
Q

What data rates can be
used by ADPCM?

A

40, 32, 24, and 16 kb/s
TDMM.* Page 1-30

203
Q

What device is used to
convert speech to a digital
signal and its subsequent
decoding to speech?

A

Codec
TDMM.* Page 1-30

204
Q

At what rates can vocoders
transmit speech?

A

8 to 2.4 kbs
TDMM.* Page 1-30

205
Q

What do lower bit rates
typically imply about a
signal’s quality?

A

That the signal quality
is degraded
TDMM.* Page 1-30

206
Q

What process involves
combining binary data from
several different sources
into a single composite
bit stream?

A

Time division multiplexing
(TDM)
TDMM.* Page 1-31

207
Q

What is the purpose
of TDM?

A

To increase the information-
carrying capacity of the digital
telecommunications channel
TDMM.* Page 1-31

208
Q

How is TDM
accomplished?

A

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
Q

What is the most popular
form of TDM?

A

Statistical TDM
TDMM.* 1-31

210
Q

In the DSI format, the
digital data from — speech
channels is combined for
transmission over a single
transmission channel.

A

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
Q

What is the data rate for
the DSI format?

A

1.544 Mb/s
TDMM.* Page 1-32

212
Q

Describe the
CEPT PCM-30 format.

A

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
Q

What is the data rate for
the CEPT PCM-30 format?

A

2.048 Mb/s
TDMM.* Page 1-32

214
Q

What term is used to
describe the process of
reconstituting the individual
channels from the
composite signal?

A

Demultiplexing
TDMM.* Page 1-32

215
Q

What is a channel bank?

A

Multiplexing and demultiplexing
equipment
TDMM.* Page 1-32

216
Q

What stages of
multiplexing contain
A/D conversion?

A

Only the first order multiplexing stage (T1 and E1)
TDMM.* Page 1-32 1

217
Q

In the United States, how
many Tl frames are
needed to create a
superframe?

A

12
TDMM.* Page 1-33

218
Q

In Europe, how many E1 frames are needed to create a multiframe?

A

16
TDMM.* Page 1-33

219
Q

What is the basic unit of
digital data?

A

Bit
TDMM.* Page 1-33

220
Q

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.

A

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
Q

What is the final step in the
encoding process?

A

The modification of the shape
and pattern of pulses to achieve
more efficient transmission
TDMM.* Page 1-33

222
Q

What is the line-encoding
technique designed to do?

A

*Eliminate the dc component
Improve timing recovery
TDMM. Page 1-33

223
Q

What encoding technique is
used for Tl carriers?

A

Bipolar alternate mark inversion
(AMI)
TDMM.* Page 1-33

224
Q

What type of encoding
allows signal transition to
occur in the middle of every
bit interval?

A

Manchester encoding
TDMM.* Page 1-33

225
Q

What term is used to
describe the rate at which a
signal can change states?

A

Baud
TDMM.* Page 1-34

226
Q

What transmission
method is used for
ISDN (basic rate)?

A

2BIQ
TDMM.* Page 1-35, Table 1.10

227
Q

What transmission
method is used for
ISDN (primary rate)?

A

Bipolar
TDMM: Page 1-35, Table 1.10

228
Q

What transmission method
is used for HDSL?

A

2BIQ
TDMM: Page 1-35, Table 1.10

229
Q

What transmission method
is used for 10 BASE-T?

A

Manchester
TDMM: Page 1-35, Table 1.10

230
Q

What is the encoding rate for ISDN (basic rate)?

A

160 kb/s
TDMM.* Page 1-35, Table 1.10

231
Q

What is the encoding rate
for ISDN (primary rate)?

A

1.544 Mb/s
TDMM.* Page 1-35, Table 1.10

232
Q

What is the encoding
rate for HDSL?

A

2 x 784 kb/s
TDMM.* Page 1-35, Table 1.10

233
Q

What is the encoding rate for 10BASE-T?

A

10 Mb/s
TDMM.* Page 1-35, Table 1.10

234
Q

What is a QAM signal?

A

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
Q

Which QAM sinusoid is the
equivalent of a sine wave?

A

I signal
TDMM.* Page 1-37

236
Q

Which QAM sinusoid is the
equivalent of a cosine wave?

A

Q signal
TDMM.* Page 1-37

237
Q

What type of modulation
does DMT use?

A

Multicarrier modulation
TDMM.* Page 1-37

238
Q

How can data rates be
adjusted with DMT?

A

By increasing the number of
sub-bands and by varying the
number of bits carried
in each sub-band
TDMM.* Page 1-37

239
Q

Which line application uses
8B/1Q4 PAM 5 encoding?

A

1000BASE4
TDMM.* Page 1-37

240
Q

Name 3 types of
transmission circuits.

A

1 .Simplex
2.Half-dupIex
3.FuIl-duplex
TDMM.* Page 1-39

241
Q

What is simplex
transmission?

A

The transmission of signals in
one direction only
TDMM.* Page 1-39

242
Q

What is half-duplex
transmission?

A

The transmission of signals in in
either direction, but in one
direction at a time
TDMM.* Page 7-39

243
Q

What is full-duplex
transmission?

A

The transmission of signals in
both directions at the same time
TDMM.* Page 1-39

244
Q

Why is asynchronous
transmission a popular method
of telecommunications among
microcomputer users?

A

Because of a common
standardized interface and
protocol between machines
TDMM.* Page 1-40

245
Q

Why is asynchronous transmission less efficient than synchronous
transmission?

A

Because it requires the addition of some combination of start and stop bits to the data stream
TDMM.* Page 1-40

246
Q

How is synchronous
transmission performed?

A

By synchronizing the data bits in
phase or in unison with equally
spaced clock signals or pulses
TDMM.* Page 1-40

247
Q

What is used to prevent
confusion of the characters
in the data stream?

A

Clocking pulses
TDMM.* Page 1-40

248
Q

Who are the intended users
of basic rate ISDN?

A

Residential and
small business users
TDMM.* Page 7-41

249
Q

What is the total
information capacity
of basic rate ISDN?

A

144 kb/s (line rate = 160 kb/s)
TDMM.* Page 7-41

250
Q

Who are the intended users
of primary rate ISDN
North America?

A

Large business users
TDMM.* Page 7-47

251
Q

What is the total
information capacity
of primary rate ISDN
North America?

A

1.536 Mb/s
(line rate = 1.544 Mb/s)
TDMM.* Page 7-47

252
Q

Delay Skew

A

The difference in propagation
delay between any pairs within
the same cable sheath.
TDMM.* Page 7-55

253
Q

What is the total
information capacity
of primary rate ISDN
Europe?

A

1.92 Mb/s (line rate = 2.048 Mb/s)
TDMM.* Page 1-41

254
Q

Dispersion

A
  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
Q

HDSL requires no repeaters on lines less than ________ for 24 AWG.

A

HDSL requires no repeaters on lines less than 3600 m (11,811 ft) for 24 AWG.

TDMM.* Page 1-42

256
Q

What has effectively
replaced HDSL?

A

SDSL and other xDSL
technologies

257
Q

what is SDSL?

A

A single-pair version of HDSL,
transmitting up to DS1 rate
signals over a single balanced
twisted-pair
TDMM.* Page 1-42

258
Q

What is distance
limitation for SDSL?

A

-3000 m (9842 ft)
TDMM.* Page 1-42

259
Q

What does asymmetric
describe about ASDL
technologies?

A

That they allow more bandwidth
downstream (server to client)
than they do upstream
(client to server)
TDMM.* Page 1-43

260
Q

What down-to-upstream
ratio is required for good
Internet performance?

A

At least 10:1
TDMM.* Page 1-43

261
Q

What do ADSL modems
use to reduce errors
caused by impulse noise?

A

Forward error correction (FEC)
TDMM.* Page 1-44

262
Q

What does RADSL allow the
access provider (AP)
to adjust?

A

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
Q

How does RADSL increase
the percentage of users
served by DSL services?

A

By extending the possible
distance from the subscriber
to the AP facility
TDMM.* Page 7-44

264
Q

What are the target ranges of
VDSL downstream rates?

A

*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
Q

What are the general ranges
of VDSL upstream rates?

A

*1.6 to 2.3 Mb/s
19.2 Mb/s
* Equal to downstream
TDMM. Page 1-45

266
Q

How much delay is
introduced by interleaving?

A

In the order of 40 times
the maximum length
correctable impulse
TDMM.* Page 1-45

267
Q

What is a baseband analog
video signal?

A

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
Q

Name 2 types of
baseband signaling.

A

1 .Composite
2.Component
TDMM.* Page 7-46

269
Q

What information is
contained in a composite
format analog signal?

A

All the components necessary to
construct a monochrome or
color picture but no audio
information
TDMM.* Page 1-46

270
Q

What colors are used to
create a color video
picture?

A

Red, green, blue (RGB)
TDMM.* Page 7-47

271
Q

How does a component
video keep the three-color
components of an
image separate?

A

With three cables
TDMM.* Page 1-47

272
Q

Why is the RGB signal
separated from the
luminance signal in a
component video?

A

To minimize crosstalk and
permit higher resolution
TDMM.* Page 1-47

273
Q

How is RGB signaling
typically used?

A

For high-end graphic
workstations where the need
for higher-quality imaging
is required
TDMM.* Page 7-47

274
Q

What does an RF carrier
represent?

A

TV channel
TDMM.* Page 1-47

275
Q

Which categories of
balanced twisted-pair
cabling support baseband
composite signaling?

A

Category 3/class C or higher
(for a minimum of zl 00 m [328
ft])
TDMM: Page 1-47

276
Q

Which categories of
balanced twisted-pair
cabling support RGB
component signaling?

A

Category 3/class C or higher (for a minimum of ~100 m [328 ft] using passive media adapters)
TDMM.* Page 1-47

277
Q

Which categories of
balanced twisted-pair
cabling support broadband
analog CATV signaling?

A

Category 5e/class D or higher
TDMM.* Page 7-47

278
Q

What are the components of an
idealized transmission line?

A

Two conductors separated by a
dielectric material uniformly
spaced over the line’s length
TDMM.* Page 1-48

279
Q

What was the basis of the
earliest functional model of
a transmission line?

A

Resistive loss
TDMM.* Page 1-48

280
Q

How can a transmission
line be represented?

A

By an electrical circuit
containing only passive
components that are arranged in
a ladder network
TDMM.* Page 7-51

281
Q

Name the 4 primary
transmission line
parameters.

A

1 .Series resistance
2.Series inductance
3.Mutual capacitance
4.Mutual conductance
TDMM.* Page 7-51

282
Q

What is series resistance?

A

The loop resistance of a pair of
conductors for an incremental
length
TDMM.* Page 1-51

283
Q

What unit of measure is
used to express series
resistance?

A

Ohms
TDMM.* Page 1-51

284
Q

What is series inductance?

A

The loop inductance of a pair of
conductors for an incremental
length
TDMM.* Page 1-51

285
Q

What unit of measure is
used to express series
inductance?

A

Henries (H)
TDMM.* Page 1-51

286
Q

What is mutual
capacitance?

A

The capacitance between a
pair of conductors for an
incremental length
TDMM.* Page 1-51

287
Q

What unit of measure is used to express mutual inductance?

A

Henries (H)
TDMM: Page 1-51

288
Q

How can the secondary
parameters of a
transmission line be
determined?

A

Calculated from the primary parameters.
Obtained by direct measurement.
TDMM.* Page 1-51

289
Q

What unit of measure is
used to express mutual
conductance?

A

Siemens (S)
TDMM.* Page 7-51

290
Q

What forms the foundation
of EM wave theory?

A

Maxwell’s equations
TDMM.* Page 1-52

291
Q

How can the secondary parameters of a transmission line be determined?

A

*By calculating the primary parameters
By direct measurement
TDMM. Page 1-52

292
Q

When is maximum power transferred from the source to the load?

A

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
Q

What term refers to the
ratio of output to input
power (or voltage) where
the terminations are
perfectly matched?

A

Attenuation
TDMM.* Page 1-53

294
Q

What term describes signal
interference between cable
pairs?

A

Crosstalk
TDMM.* Page 1-54

295
Q

How is NVP for balanced
twisted-pair cables
expressed?

A

As a percentage of
the speed Of light
TDMM.* Page 1-54

296
Q

What is the range of typical
NVP values for 100-ohm
balanced twisted-pair
cables?

A

.56c to .74c
TDMM.* Page 1-54

297
Q

What term is used to
describe the difference in
propagation delay between
any pairs within the same
cable sheath?

A

Delay skew
TDMM.* Page 7-55

298
Q

What term describes the
ratio between the
transmitted power and the
reflected power?

A

Return loss
TDMM.* Page 1-55

299
Q

What is signal-to-noise
ratio (SNR)?

A

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
Q

How is attenuation-to-crosstalk ratio (ACR) obtained?

A

By subtracting the attenuation (dB) from near-end crosstalk (NEXT) (dB)
TDMM.* Page 1-56

301
Q

How is ACR normally
stated?

A

At a given frequency
TDMM.* Page 1-56

302
Q

What is power sum
attenuation-to-crosstalk
ratio (PSACR)?

A

A ratio in decibels determined by
subtracting the attenuation from
PSNEXT loss between cables or
channels in close proximity
TDMM.* Page 1-56

303
Q

What is power sum
attenuation-to-alien-
crosstalk ratio at the near
end (PSAACRN)?

A

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
Q

What is power sum
attenuation-to-alien-
crosstalk ratio at the far
end (PSAACRF)?

A

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
Q

How do the cabling
standards define a
channel?

A

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
Q

What is the nominal
characteristic impedance
of balanced twisted-pair
cables?

A

100 ohms at 100 MHz
TDMM.* Page 1-57

307
Q

Name the 3 most important
parameters that affect the
performance of balanced
twisted-pair cable in
network cabling.

A

1 . Insertion loss
2. PSNEXT loss
3. Return loss
TDMM: Page 1-59

308
Q

What is channel
insertion loss?

A

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
Q

What is NEXT loss
in a channel?

A

The vector sum of crosstalk
induced in the cable, connectors,
and patch cords
TDMM.* Page 1-59

310
Q

What is power sum equal
level far-end crosstalk
(PSELFEXT)?

A

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
Q

What determines the
available channel
bandwidth for a specified
channel?

A

The range of frequencies that
can be successfully transmitted
for a given distance
TDMM.* Page 1-60

312
Q

What is the dominant noise
source for most LAN
systems today?

A

NEXT interference between all
transmit pairs and receive pairs
TDMM.* Page 1-60

313
Q

How much horizontal
cabling may be used in a
permanent link?

A

Up to -90 m (295 ft)
TDMM.* Page 1-62

314
Q

True or False
The transmission categories
of all components used in the
same cabling system must
be matched.

A

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
Q

What category/class of
balanced twisted-pair cable
provides the minimum
acceptable performance
level for network cabling?

A

Category 3/class C
TDMM.* Page 1-64

316
Q

What category/class of
balanced twisted-pair cable
is recommended as the
minimum by most
standards?

A

Category 5e/class D
TDMM.* Page 7-64

317
Q

What category/class of
balanced twisted-pair cable
represents BICSI best
practices for network cabling?

A

Category 6/class E
TDMM: Page 1-64

318
Q

What frequency is supported
by Category 3/class C cable?

A

16 MHz
TDMM: Page 1-64, Table 1.15

319
Q

What frequency is supported
by Category 5/class D cable?

A

100 MHz
TDMM.* Page 7-64, Table 1.75

320
Q

What frequency is supported
by Category 6/class E cable?

A

250 MHz
TDMM.* Page 7-64, Table 1.75

321
Q

How many 10BASE-T systems having Cat 3 transmission characteristics can share a binder group ?

A

No more than 12
TDMM.* Page 1-72

322
Q

Name 3 advantages of media conversion to balanced twisted-pair.

A
  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
Q

Name the 3 main
categories of terminal
interfaces.

A
  1. Impedance-matching devices
  2. Signal converters
  3. Media filters
    TDMM.* Page 7-73
324
Q

How are baluns used?

A

To adapt the balanced impedance of twisted-pairs to the unbalanced impedance of coaxial cables
TDMM.* Page 1-73

325
Q

Where are baluns required?

A

Wherever a transition is made from twisted-pair to coaxial or from coaxial to twisted-pair
TDMM.* Page 1-73

326
Q

What is a signal converter?

A

An electronic device that
receives one type of signal and
outputs another type of signal
TDMM.* Page 1-73

327
Q

Name 2 advantages of
signal converters.

A

1 .Decrease the risk of transmission and EMI problems.
2. Extend the unbalanced signal reach of a DTE.
TDMM.* Page 1-73

328
Q

What is the purpose of a
media filter?

A

To eliminate unwanted
frequencies affecting link
performance that could radiate
from the balanced twisted-pair
cable
TDMM.* Page 7-74

329
Q

What is a transceiver?

A

A radio frequency device
capable of sending and
receiving radio frequencies
TDMM.* Page 1-74

330
Q

Name 4 benefits of
combining power and data
onto a single cable.

A
  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
Q

What is the maximum
power output for
Type 1 POE?

A

15.4 W from the PSE with up to
12.95 W delivered to the PD
TDMM: Page 1-76

332
Q

What is the maximum
power output for
Type 2 POE?

A

30 W from the PSE with up to
25.5 W delivered to the PD
TDMM.* Page 1-76

333
Q

What is the maximum
power output for
Type 3 POE?

A

60 W from the PSE with up to
51 W delivered to the PD
TDMM.* Page 7-75

334
Q

What is the maximum
power output for
Type 4 POE?

A

90 W from the PSE with up to
73 W delivered to the PD
TDMM.* Page 1-75

335
Q

What is link layer discovery
protocol (LLDP)?

A

Type 3 or 4 PSE power
classification information
exchanged during initial
negotiation
TDMM.* Page 1-76

336
Q

Name 3 practical power
sourcing equipment (PSE)
options for POE.

A

1 .Endspan devices
2.Midspan devices
3.LocaI power sources
TDMM.* Page 1-77

337
Q

Name the 3 elements
of a simple model
telecommunications
system.

A

1 .Transmitter
2.Receiver
3.Medium
TDMM.* Page 1-78

338
Q

What is the purpose of an
optical transmitter?

A

To convert electrical signals to
optical signals for transmission
over an optical fiber cable
TDMM.* Page 1-78

339
Q

What are the 4 nominal
wavelengths of optical fiber
transmitters?

A

1.850 nm
2.1300 nm
3.1310 nm
4.1550 nm
TDMM.* Page 1-78

340
Q

What term refers to the
range of wavelengths over
which the total power
emitted by a transmitter is
distributed?

A

Spectral width
TDMM.* Page 7-80

341
Q

What unit of measure is
typically used to specify
spectral width?

A

Nanometer (nm)
TDMM.* Page 7-80

342
Q

How do wide spectral
widths affect the
dispersion of light pulses?

A

Wide spectral widths lead to
increased dispersion of light pulses
as the light pulses propagate
through an optical fiber.
TDMM.* Page 1-81

343
Q

What is the average power
of a transmitter?

A

The mean level of power output
of a given light source during
modulation
TDMM.* Page 1-81

344
Q

What is the modulation
frequency of a transmitter?

A

The rate at which the
transmission changes in
intensity
TDMM.* Page 1-83

345
Q

Name 3 major types of
transmitter light sources.

A

1 .LEDs
2.VCSELs
3.LDs
TDMM.* Page 1-83

346
Q

What center wavelength ranges are typical for LEDs?

A

800 to 900 nm
1250 to 1350 nm
TDMM. Page 1-83, Table 1.20

347
Q

What is the modulation
frequency of most LEDs?

A

Under 200 MHz
TDMM.* Page 1-83, Table 1.20

348
Q

What is the average
launched optical power
level Of LEDS?

A

-10 to -30 dBm into
multimode fiber
TDMM.* Page 1-83, Table 1.20

349
Q

What is the center
wavelength for short
wavelength lasers?

A

780 nm
TDMM.* Page 1-84, Table 1.21

350
Q

How does the modulation
frequency of short
wavelength lasers compare
to that of LEDs?

A

It is higher than LEDs (can
exceed 1 GHz).
TDMM.* Page 1-84, Table 1.21

351
Q

What is the average
launched optical power
level of short wavelength
lasers?

A

+1 to -8 decibels per mw (dBm)
TDMM.* Page 7-84, Table 1.21

352
Q

What are the center
wavelengths used for
VCSELs?

A

*850 nm
1300 nm
TDMM. Page 7-85, Table 1.22

353
Q

How does the modulation frequency for VCSELs compare to that of LEDs?

A

It is much higher than that of LEDs, allowing up to 56 GHz.
TDMM.* Page 1-85, Table 1.22

354
Q

What is the average
launched power level of
VCSELs?

A

-1 to -8 decibels per milliwatt
into multimode fiber
TDMM.* Page 1-85, Table 1.22

355
Q

What is the most predominate
center wavelength for laser
diodes (LDs)?

A

1310 nm
TDMM.* Page 1-86, Table 1.23

356
Q

How does the spectral
width for LDs compare to
that of LEDs?

A

Narrow in comparison
TDMM.* Page 7-86, Table 1.23

357
Q

Where are typical LD
sources used?

A

Almost exclusively in
singlemode optical fiber links
TDMM.* Page 1-86, Table 1.23

358
Q

What is the average launched optical power level of LDs?

A

Common values of +4 to -9 power level decibels per milliwatt into singlemode optical fibers
TDMM.* Page 1-86, Table 1.23

359
Q

Which type of transmitter is the most expensive: LED, VCSEL, or LD?

A

LD
TDMM.* Page 1-87, Table 1.24

360
Q

What is the primary type of
optical fiber used with LD
transmitters?

A

Singlemode
TDMM.* Page 1-87, Table 1.24

361
Q

Name the 3 characteristic
parameters of optical
fiber receivers.

A
  1. Sensitivity
  2. Bit error rate (BER)
  3. Dynamic range
    TDMM.* Page 1-88
362
Q

Define sensitivity in terms of optical fiber receivers.

A

The minimum power level an incoming signal must have to achieve an acceptable level of performance
TDMM.* Page 1-88

363
Q

What is bit error rate (BER)?

A

The fractional number of errors
allowed to occur between the
transmitter and receiver
TDMM.* Page 7-88

364
Q

What happens to the BER if the power of the incoming signal falls below the receiver sensitivity?

A

The number of bit errors will increase beyond the maximum BER specified for the receiver.
TDMM.* Page 1-88

365
Q

What is dynamic range?

A

The range of power that a receiver can process at a specified bit error rate (BER)
TDMM.* Page 1-88

366
Q

Name 3 key factors that are used to determine which optical fiber to use in a given application.

A
  1. Active equipment
  2. Distance
  3. Bandwidth (data rate)
    TDMM.* Page 1-89
367
Q

Which classes of multimode cable are recognized for use in
new installations?

A

OM3
OM4
OM5
TDMM.* Page 1-90

368
Q

Name the 2 essential determinants of the end-to-end bandwidth for an optical fiber system.

A
  1. Transmitter
  2. Optical fiber
    TDMM.* Page 1-91
369
Q

What is rise time?

A

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
Q

How does dispersion
affect a light pulse?

A

It causes the light pulse to
broaden in duration as it travels
through the optical fiber.
TDMM.* Page 1-94

371
Q

What is often used in place
of bandwidth to define
system capacity in
singlemode systems?

A

Maximum pulse distortion
TDMM.* Page 7-94

372
Q

Name the 3 effects that are combined to calculate and predict the bandwidth requirements for a multimode system.

A
  1. Transmitter rise time
  2. Optical fiber modal dispersion
  3. Chromatic dispersion
    TDMM.* Page 1-94
373
Q

What type of dispersion occurs when the wider range of wavelengths in each pulse travels at a wider range of individual speeds?

A

Chromatic dispersion
TDMM.* Page 1-95

374
Q

What is modal dispersion?

A

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
Q

What are the 2 major
classifications of optical
fiber cable?

A

1 . Singlemode
2. Multimode
TDMM: Page 1-98

376
Q

What are the 2 popular
sizes of multimode optical
fiber cables?

A

1.62.5/125
2.50/125
TDMM.* Page 1-99, Table 1.27

377
Q

What are the most
common wavelength
windows for optical fiber
cables?

A
  • 850 nm
  • 1300 nm
  • 1550 nm
    TDMM.* Page 1-701
378
Q

What is the characteristic core diameter for singlemode optical fiber?

A

Between 8 and 9 um
TDMM.* Page 1-102, Table 1.30

379
Q

What is the diameter of the
cladding on a singlemode
optical fiber cable?

A

125 pm
TDMM.* Page 7-102, Table 1.30

380
Q

What is bandwidth for singlemode optical fiber?

A

Greater than 20 GHz
TDMM.* Page 71-102, Table 1.30

381
Q

What are the operating
wavelengths for
singlemode optical fiber?

A

*1310 nm
1550 nm
TDMM. Page 1-102, Table 1.30

382
Q

What establishes the
maximum supportable
distance for optical
fiber cables?

A

Application standards
TDMM.* Page 1-103

383
Q

What establishes
maximum channel
attenuation?

A

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
Q

What is the maximum
attenuation value for
50/125 pm multimode
cable at 850 nm?

A

3.5 dB/km
TDMM.* Page 1-104, Table 1.31

385
Q

What is the maximum
attenuation value for
62.5/125 pm multimode
cable at 1300 nm?

A

1.5 dB/km
TDMM.* Page 1-104, Table 1.31

386
Q

What is the maximum
attenuation value for
singlemode inside plant
cable at 1310 nm?

A

1.0 dB/km
TDMM.* Page 7-704, Table 1.31

387
Q

What is the maximum
attenuation value for
singlemode outside plant
cable at 1550 nm?

A

0.4 dB/km
TDMM.* Page 1-104, Table 1.31

388
Q

How is optical fiber cable
bandwidth validated?

A

Through the manufacturer’s
specification and quality
checking of the product
specification sheets with the
installed components
TDMM.* Page 1-107

389
Q

What determines the
maximum permissible end-
to-end system attenuation
in a given link?

A

The average transmitter power
and the receiver sensitivity
TDMM.* Page 1-107

390
Q

What connector loss value
should be used for 0 to 4
connector pairs?

A

The maximum value
TDMM.* Page 1-113

391
Q

What connector loss value
should be used for 5 or
more connector pairs?

A

The typical value
TDMM.* Page 1-113

392
Q

What is the recommended
maximum loss value for
optical fiber cable
connectors?

A

0.75 dB
TDMM.* Page 1-173

393
Q

What is the average splice
loss for a fusion splice in
multimode cabling?

A

0.05 dB
TDMM.* Page 1-113, Table 1.36

394
Q

What is the maximum splice
loss for mechanical and
fusion splices in multimode
cabling?

A

0.3 dB
TDMM.* Page 1-113, Table 1.36

395
Q

How is the minimum required system loss calculated?

A

By subtracting the receiver’s dynamic range from the system gain
TDMM.* Page 1-114

396
Q

What device can be used to
add additional loss to an
optical fiber system?

A

Attenuator
TDMM.* Page 1-115

397
Q

Name the 2 standards that
have been established for
optical fiber carrier
transmissions.

A

1 .Synchronous Optical Network
(SONET)-North America
2.Synchronous Digital Hierarchy
(SDH)—lnternational
TDMM.* Page 1-716

MJ Class (23 decks)

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