Chapter 1 - Part 1 Flashcards
1
Q
Amplitude
A
The maximum absolute value reached by a voltage or current waveform.
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2
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.
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3
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.
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4
Q
Attenuation
A
The ratio in decibels of the output power (or voltage) to the input power (or voltage) when the load and source impedance are matched to the characteristic impedance of the cable.
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5
Q
ATM
A
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 DELAYS. ATM IS DESIGNED TO TAKE ADVANTAGE OF HIGH-SPEED TRANSMISSION MEDIA, SUCH AS E3, SYNCHRONOUS OPTICAL NETWORK (SONET), AND T3.
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6
Q
AWG
A
AMERICAN WIRE GUAGE
A SYSTEM USED TO SPECIFY WIRE SIZE. THE GREATER THE WIRE DIAMETER, THE SMALLER THE AWG VALUE.
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7
Q
BANDWIDTH
A
A RANGE OF FREQUENCIES AVAILABLE FOR SIGNALING EXPRESSED IN HERTZ (Hz). IT IS USED TO DENOTE THE POTENTIAL FOR INFORMATION HANDLING CAPACITY OF THE MEDIUM, DEVICE, OR SYSTEM.
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8
Q
BROADBAND CABLE
A
COMPOSITE BASEBAND VIDEO AND AUDIO SIGNALS THAT ARE AMPLITUDE AND FREQUENCY MODULATED, RESPECTIVELY, WITH AN RF CARRIER IN ACCORDANCE WITH THE VIDEO AND AUDIO INFORMATION THAT NEED TO BE CONVEYED (E.G., CATV).
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9
Q
CO
A
CENTRAL OFFICE
A COMMON CARRIER SWITCHING CENTER OFFICE (ALSO CALLED A PUBLIC EXCHANGE) THAT IS CONVIENIENTLY 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.
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10
Q
CODEC
A
A DEVICE THAT CONVERTS SPEECH TO A DIGITAL SIGNAL AND ITS SUBSEQUENT DECODING TO SPEECH.
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11
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.
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12
Q
DECIBEL
A
A LOGARITHMIC UNIT OF MEASURING THE RELATIVE VOLTAGE, CURRENT, OR POWER OF A SIGNAL. ONE TENTH OF A BEL.
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13
Q
DELAY SKEW
A
THE DIFFERENCE IN PROPOGATION DELAY BETWEEN ANY PAIRS WITHIN THE SAME CABLE SHEATH.
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14
Q
DIGITAL SIGNAL
A
INFORMATION USED BY THE DIGITAL DEVICES IN THE FORM OF A SEQUENCE OF DISCRETE PULSES (E.G., A BINARY SIGNAL WITH 2 VALUES USED TO TRANSMIT THE 2 STATES {0, 1}).
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15
Q
DISPERSION
A
- THE LOSS OF A SIGNAL RESULTING FROM THE SCATTERING OF LIGHT PULSES AS THEY ARE TRANSMITTED THROUGH A MEDIUM.
- THE WIDENING OR SPREADING OUT OF THE MODES IN A LIGHT PULSE AS IT PROGRESSES ALONG AN OPTICAL FIBER.
- THE CHARACTERISTICS OF THE SOUND COVERAGE FIELD OF A SPEAKER.
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16
Q
EMI
A
ELECTROMAGNETIC INTERFERENCE
STRAY ELECTRICAL ENERFY RADIATED FROM ELECTRONIC EQUIPMENT AND ELECTRONICS SYSTEMS (INLCUDING CABLING).
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17
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.
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18
Q
IP
A
INTERNET PROTOCOL
THE OPEN SYSTEMS INTERCONNECTION (OSI) REFERENCE MODEL LAYER 3 (NETWORK LAYER) PROTOCOL MOST COMMONLY USER FOR INTERNETWORKING. REQUIRED FOR COMMUNICATIONS OVER THE INTERNET.
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19
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 (PTSN). DIFFERENT VERSIONS AND CONFIGURATIONS EXIST REGIONALLY AND INTERNATIONALLY.
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20
Q
NVP
A
NOMINAL VELOCITY PF PROPOGATION
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 PROPOGATION.
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21
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.
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22
Q
PHASE
A
- THE RELATIONSHIP IN TIME BETWEEN 2 WAVEFORMS OF THE SAME FREQUENCY.
- THE RELATIONSHIP IN TIME BETWEEN 2 PARAMETERS OF A SINGLE WAVEFORM (E.G., VOLTAGE AND CURRENT).
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23
Q
PoE
A
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, CAMERA, TELEPHONE SET).
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24
Q
PROPOGATION DELAY
A
THE TIME REQUIRED FOR A SIGNAL TO TRAVEL FROM ONE END OF THE TRANSMISSION PATH TO THE OTHER END. (TIA)
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25
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.G., 2, 4, 8, 16, 32, 64, 128, 256).
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26
SINUSOID
AN OSCILATING, PERIODIC SIGNAL THAT IS COMPLETELY DESCRIBED BY 3 PARAMETERS: AMPLITUDE, FREQUENCY, AND PHASE.
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27
TDM
TIME DIVISION MULTIPLEXING
A PROCESS THAT COMBINES BINARY DATA FROM SEVERAL DIFFERENT SOURCES (E.G., VOICE CHANNELS) INTO A SINGLE COMPOSITE BIT STREAM.
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28
WHAT IS AN ELECTRICAL CONDUCTOR?
ANY MATERIAL THAT CAN CARRY AN ELECTRIC CHARGE FROM ONE POINT TO ANOTHER
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29
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
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30
SILVER AND GOLD ARE GOOD CONDUCTORS, BUT THEY ARE NOT GENERALLY USED FOR ICT WIRES AND CABLES. WHY?
HIGH COSTS
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31
WHICH CONDUCTOR SETS THE STANDARD FOR COMPARING THE CONDUCTIVITY OF OTHER METALS?
COPPER
TDMM: PAGE 1-3, TABLE 1.1
32
WHAT TYPE OF COPPER IS USED TO SET THE REFERENCE VALUE?
ANNEALED COPPER
TDMM: PAGE 1-3, TABLE 1.1
33
WHAT TYPE OF CONDUCTOR IS TYPICALLY USED FOR AEIRAL, SELF-SUPPORTING DROP WIRE?
COPPER-COVERED
TDMM: PAGE 1-3, TABLE 1.1
34
HOW DOS THE ALLOYING OF PURE COPPER AFFECT ITS CONDUCTIVITY?
THE ALLOYING OF PURE COPPER ALWAYS HAS ADVERSE EFFECT ON ITS CONDUCTIVITY.
TDMM: PAGE 1-3, TABLE 1.1
35
HOW DOES THE CONDUCTIVITY OF ALUMINUM COMPARE THE CONDUCTIVITY OF COPPER?
IT HAS ABOUT 60% CONDUCTIVITY COMPARED TO COPPER.
TDMM: PAGE 1-3, TABLE 1.1
36
WHAT ARE ALUMINUM CONDUCTORS COMMONLY USED?
IN ELECTRICAL UTILITY DISTRIBUTION LINES
TDMM: PAGE 1-3, TABLE 1.1
37
WHICH TYPE OF SOLID CONDUCTOR HAS THE POOREST CORROSION RESISTANCE?
HIGH STRENGTH ALLOY
TDMM: PAGE 1-4, TABLE 1.2
38
WHAT TYPE OF SOLID CONDUCTOR HAS THE POOREST OXIDATION RESISTANCE?
ALUMINUM
TDMM: PAGE 1-4, TABLE 1.2
39
WHICH TYPE OF SOLID CONDUCTOR HAS THE BEST TENSILE STRENGTH?
HIGHSTRENGTH ALLOY
TDMM: PAGE 1-4, TABLE 1.2
40
WHICH TYPE OF SOLID CONDUCTOR HAS THE BEST DUCTILITY?
HIGH STRENGTH ALLOY
TDMM: PAGE 1-4, TABLE 1,2
41
WHAT IS THE CONDUCTIVITY FOR A HIGH STRENGTH ALLOY CONDUCTOR?
85% OF TYPICAL
TDMM: PAGE 1-4, TABLE 1.2
42
HOW ARE STRANDED CONDUCTORS CREATED?
BY BUNDLING TOGETHER A NUMBER OF SMALL GUAGE SOLID CONDUCTORS TO CREATE A SINGLE, LARGER CONDUCTOR.
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43
NAME 4 ADVANTAGES OF SOLID CONDUCTORS
1. LESS COSTLY
2. LESS COMPLEC TERMINATION SYSTEMS
3. BETTER TRANSMISSION PERFORMANCE AT HIGHER FREQUENCIES
4. LESS RESISTANCE.
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44
NAME 3 ADVANATAGES OF STRANDED CONDUCTORS
1. MORE FLEXIBLE
2. LONGER FLEX LIFE
3. LESS SUCCEPTIBLE TO DAMAGE DURING CRIMP TERMINATION PROCESS
45
WHAT IS A COMPOSITE CONDUCTOR?
A CONDUCTOR CONSTRUCTED FROM NONTRADITIONAL MATERIALS (E.G., METALLIC RESINS OR GRAPHITE)
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45
NAME 5 ADVANTAGES OF COMPOSITE CONDUCTORS
1. HIGHLY FLEXIBLE
2. LIGHTWEIGHT
3. INEXPENSIVE AND EASY TO PRODUCE
4. EASILY EMBEDDED INTO OTHER MATERIALS
5. LOW COEFFICIANT OF EXPANSION
46
NAME 4 DISADVANTAGES OF COMPOSITE CONDUCTORS
1. POOR ANALOG TRANSMISSION CHARACTERISTICS INCLUDING HIGH ATTENTUATION, ESPECIALLY ABOVE 4OOO Hz
2. POOR DIGITAL TRANSMISSION CHARACTERISTICS
3. EASILY DAMAGED UNLESS ENCASED IN A RIGID MATERIAL
4. INCONSISTENT QUALITY
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47
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.
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48
WHY IS THE AWG SYSTEM IMPORTANT?
BECASUE IT PROVIDES A STANDARD REFERENCE FOR COMPARING VARIOUS CONDUCTOR MATERIALS
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49
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.
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50
HOW DO DIELECTRICS REDUCE EM COUPLING BETWEEN CONDUCTORS?
BY INCREASING THE CONDUCTOR SEPARATION.
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51
WHAT IS DIELECTRIC CONSTANT?
THE RATIO OF CAPACITANCE OF AN INSULATED CONDUCTOR TO THE CAPACITANCE OF THE SAME CONDUCTOR UNINSULATED IN THE AIR.
TDMM: PAGE 1-8, TABLE 1.4
52
WHAT DOES DIELECTRIC STRANGTH MEASURE?
THE MAXIMUM VOLTAGE THAT AN INSULATION CAN WITHSTAND WITHOUT BREAKDOWN
TDMM: 1-8, TABLE 1.4
53
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
54
WHAT IS INSULATION RESISTANCE?
THE INSULATIONS ABILITY TO RESIST THE FLOW OF CURRENT THROUGH IT.
TDMM: PAGE 1-9, TABLE 1.4
55
HOW IS INSULATION RESISTANCE TYPICALLY EXPRESSED?
IN MEGAOHM/km OR MEGAOHM/1000 ft
TDMM: PAGE 1-8, TABLE 1.4
56
HOW DOES CABLE LENGTH AFFECT CABLE RESISTANCE?
AS THE CABLE LENGTH INCREASES, THE INSULATION RESISTANCE BECOMES SMALLER.
TDMM: PAGE 1-8, TABLE 1.4
57
WHAT IS THE MAIN REASON FOR TWISTING CONDUCTOR PAIRS?
TO MINIMIZE CROSSTALK AND NOISE BY DECRESING THE CAPACITANCE UNBALANCE AND MUTUAL INDUCTANCE COUPLING BETWEEN PAIRS.
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58
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.
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59
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 MEASURE ON ANOTHER PAIR IN CLOSE PROXIMITY
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60
HOW IS CROSSTALK WITHIN A MULTIPAIR CABLE MINIMIZED?
BY GIVING EACH PAIR A DIFFERENT TWIST LENGTH WITHIN A STANDARD RANGE
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61
WHAT YPE OF TWIST IS GENERALLY USED FOR VOICE AND LOW-FREQUENCY CABLES?
A COUNTERCLOCKWISE TWIST LENGTH BETWEEN 50mm AND 150mm (1.97" AND 6")
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62
WHAT IS TIGHT TWISTING?
CREATING PAIR TWIST LENGTHS THAT ARE LESS THAN 12.7mm (.5")
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63
WHERE IS TIGHT TWISTING COMMONLY USED?
WITHIN AND BETWEEN COMPUTERS AND OTHER DATA PROCESSING EQUIPMENT.
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64
WHICH CABLE CATEGORIES EMPLOY TIGHT TWISTING FOR OPTIMUM TRANSMISSION PERFORMACE?
CATEGOR 5e, 6, 6A AND HIGHER
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65
WHAT TERM IS USED TO REFER TO STRAY ELECTRICAL RADIATED FROM EQUIPMENT AND ELECTRONIC SYSTEMS?
ELECTROMAGNETIC INTERFERENCE (EMI)
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66
AT WHAT TEMPERATURE DOES ATTENTUATION INCREASE IN BALANCED TWISTED-PAIR CABLES?
ABOVE 20°C (68°F)
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67
WHAT TEMPERATURE REFERENCE IS CITED IN CABLING STANDARDS FOR ALL TWISTED-PAIR CABLES?
20°C +/- 3°C (68°F +/- 5.4°F)
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68
WHAT IS A CABLE SHIELD?
A METALLIC COVERING OR ENVELOPE ENCLOSING AN INSULATED CONDUCTOR, INDIVISUAL GROUP OF CONDUCTORS WITHIN A CORE, AND CABLE CORE.
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69
NAME 3 POTENTIAL BENEFITS OF USING A CABLE SHIELD IF IT IS PROPERLY TERMINATED, BONDED AND GROUNDED.
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.
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70
NAME 3 FACTORS THAT CAN AFFECT A SHIELD'S EFFECTIVENESS.
1. TYPE AND THINCKNESS OF THE SHIELD MATERIAL.
2. NUMBER AND SIZE OF OPENINGS IN THE SHIELD.
3. EFFECTIVENESS OF THE BONDING CONNECTION TO GROUND.
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71
HOW IS THE SHIELD EFFECTIVENESS DETERMINED?
BY MEASURING THE SURFACE TRANSFER IMPEDANCE.
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72
WHAT IS SURFACE TRANSFER IMPEDANCE?
THE RATIO OF THE CONDUCTOR-TO-SHIELD VOLTAGE PER UNIT LENGTH TO THE SHIELD CURRENT.
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73
WHY ARE SOLID METAL TUBES INAPPROPRIATE FOR MOST CABLE APPLICATIONS?
BECAUSE OF THE RIGID NATURE
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74
NAME 4 PRIMARY CRITERIA FOR SELECTING CABLE SHEILDS.
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
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75
WHAT TYPE OF CABLE SHIELD HAS POOR TENSILE STRENGTH?
FOIL (FOIL AND BRAID)
TDMM: PAGE 1-15, TABLE 1.5
76
WHICH TYPE OF CABLE SHIELD IS THE LEAST EFFECTIVE FOR RADIO FREQUENCY?
FLEXIBLE CONDUIT.
TDMM: PAGE 1-15, TABLE 1.5
77
WHAT TYPE OF CABLE SHIELD HAS A POOR FATIGUE LIFE?
SOLID CONDUIT
TDMM: PAGE 1-15, TABLE 1.5
78
WHICH CABLE SHIELDS HAVE EXCELLENT TENSILE STRENGTH?
1, SINGLE-LAYER BRAID
2. MULITPLE-LAYER BRAID
3. SOLID CONDUIT
TDMM: PAGE 1-15, TABLE 1.5
79
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
80
NAME 2 REASONS FOR USING A DRAIN WIRE.
1. TO PROVIDE AN EASIER MEANS FOR GROUNDING THE SHIELD.
2. TO ENSURE SHIELD CONTINUITY FOR METALLIC FOIL SHIELDS.
TDMM: PAGE 1-16
81
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
82
WHAT IS AN ANALOG SIGNAL?
A WAVE THAT USES CONTINUOUS VARIATIONS IN TIME TO TRANSMIT INFORMATION.
TDMM: PAGE 1-17
83
WHAT IS THE MOST FUNDAMENTAL CONCEPT OF AN ANALOG SIGNAL?
SINUSOID
TDMM: PAGE 1-17
84
NAME THE 3 PARAMETERS USED TO DESCRIBE A SINUSOID.
1. AMPLITUDE
2. FREQUENCY
3. PHASE
TDMM: PAGE 1-18
85
WHAT IS THE STANDARD UNIT OF FREQUENCY MEASUREMENT?
HERTZ (Hz)
TDMM: PAGE 1-18
86
WHAT FORMULA IS USED TO REPRESENT THE RELATIONSHIP BETWEEN CYCLE TIME AND FREQUENCY?
f= 1/T
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87
WHAT IS THE TYPICAL RANGE OF FREQUENCIES THAT HUMANS CAN HEAR?
20 Hz TO 20,000 Hz
TDMM: PAGE 1-18
88
WHAT RANGE OF FREQUENCIES IS TYPICALLY USED FOR VOICE TELEPHONE CIRCUITS?
300 Hz TO 3,400 Hz
TDMM: PAGE 1-18
89
WHAT IS PHASE?
A DESCRIPTION OF THE REFERENCE TIME, t= 0
TDMM: PAGE 1-19
90
HOW MANY DEGREES ARE IN A CYCLE?
360 DEGREES
TDMM: PAGE 1-19
91
WHAT IS A SIGNAL'S SPECTRUM?
A SUM OF SINUSOIDAL SIGNALS THAT DIFFER IN AMPLITUDE, FREQUENCY, AND PHASE.
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92
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.
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93
WHAT DEFINES THE ANALOG SIGNAL'S BANDWIDTH?
THE FREQUENCY RANGE OF THE SINUSIODAL SIGNALS NEEDED TO DESCRIBE AN ANALOG SIGNAL.
TDMM: PAGE 1-20
94
WHAT IS THE FREQUENCY RANGE OF THE VERY LOW FREQUENCY BAND (VLF)
3 TO 30 kHz
TDMM: PAGE 1-20, TABLE 1.7
95
WHAT IS THE FREQUENCY RANGE OF THE LOW FREQUENCY BAND (LF)?
30 TO 300 kHz
TDMM: PAGE 1-20, TABLE 1.7
96
WHAT IS THE FREQUENCY RANGE OF MEDIUM FREQUENCY BAND (MF)?
300 TO 3000 kHz
TDMM: PAGE 1-20, TABLE 1.7
97
WHAT IS THE FREQUENCY RANGE OF HIGH FREQUENCY BAND (HF)?
3 TO 30 MHz
TDMM: PAGE 1-20, TABLE 1.7
98
WHAT IS THE FREQUENCY RANGE OF THE VERY HIGH FREQUENCY BAND (VHF)?
30 TO 300 MHz
TDMM: PAGE 1-20, TABLE 1.7
99
WHAT IS THE FREQUENCY RANGE OF THE ULTRA HIGH FREQUENCY BAND (UHF)?
300 TO 3000 MHz
TDMM: PAGE 1-20, TABLE 1.7
100
WHAT IS THE FREQUENCY RANGE OF THE COMMUNITY ANTENNA TV BAND (CATV)?
54 TO 1002 MHz
TDMM: PAGE 1-20, TABLE 1.7
101
WHAT IS THE FREQUENCY RANGE OF THE SUPER HIGH FREQUENCY BAND (SHF)?
3 TO 30 GHz
TDMM: PAGE 1-20, TABLE 1.7
102
WHAT IS THE FREQUENCY RANGE OF THE ETREMELY HIGH FREQUENCY BAND (EHF)?
30 TO 300 GHz
TDMM: PAGE 1-20, TABLE 1.7
103
WHAT UNIT OF MEASURE IS OFTEN USED TO EXPRESS THE STRENGTH OF A SIGNAL?
DECIBEL (dB)
TDMM: PAGE 1-21
104
WHAT dB CHANGE OCCURS WHEN THE POWER IS DOUBLED?
+3dB
TDMM: PAGE 1-21
105
WHAT dB CHANGE OCCURS WHEN THE POWER IS REDUCED BY HALF?
-3dB
TDMM: PAGE 1-21
106
TRUE OR FALSE
DECIBEL LEVELS ARE USED TO EXPRESS POWER RATIOS OF ALL TYPES OF ANALOG AND DIGITAL SIGNALS, REGARDLESS OF MEDIUM.
TRUE. THE DECIBEL LEVELS ARE USED TO EXPRESS POWER RATIOS OF ALL TYPES OF ANALOG AND DIGITAL SIGNALS, REGARDLESS OF THE MEDIUM.
TDMM: PAGE 1-21
107
IN TELEPHONY, WHICH DELAYS ARE PERCEPTIBLE?
DELAYS GREATER THAN 50 ms IF THEY ARE OF SUFFICIENT STRENGTH.
TDMM: PAGE 1-22
108
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
109
WHAT IS THE PURPOSE OF AN ANALOG TELEPHONE?
TO CONVERT SOUND WAVES INTO ELECTRICAL ANALOG SIGNALS THAT CAN BE TRANSMITTED OVER MUCH LONGER DISTANCES THE THE SOUND WAVES CAN TRAVEL.
TDMM: PAGE 1-23
110
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
111
WHAT TYPE OF DEVICE CONVERTS ELECTRICAL ENERGY BACK INTO SOUND ENERGY?
RECEIVER
TDMM: PAGE 1-23
112
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
113
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
114
WHAT IS THE PREFFERED IMPEDANCE FOR PRIVATE LINE CIRCUITS AND TRUNKS?
600 OHMS
TDMM: PAGE 1-24
115
WHAT IS THE PREFFERED IMPEDANCE FOR CO SWITCHING SYSTEM LINE CIRCUITS?
900 OHMS
TDMM: PAGE 1-24
116
WHEN IS AN ECHO PERCEPTABLE DURING A LONG DISTANCE PHONE CALL?
WHEN PART OF THE TRANSMITTED SIGNAL IS REFLECTED BACK TO THE ORIGINATING END.
TDMM: PAGE 1-24
117
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
118
WHAT PRINCIPLE ELEMENTS CONTRIBUTE TO LOSS AND PHASE DISTORTION AT VOICE FREQUENCIES?
1. CONDUCTOR RESISTANCE
2. MUTUAL CAPACITANCE OF THE CABLE PAIR
TDMM: PAGE 1-25
119
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
120
TRUE OF 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 AFFECT ON DATA TRANSMISSION.
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121
WHAT IS THE PURPOSE OF PLACING LOAD COILS ALONG A CABLE?
TO IMPROVE SPEECH TRANSMISSION QUALITY.
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122
HOW DO LOAD COILS IMPROVE THE QUALITY OF SPEECH TRANSMISSION?
1. BY COMPENSATING FOR THE CAPACITANCE OF A CABLE PAIR.
2. BY REDUCING THE CAPACITIVE CURRENT LOADING IN THE RANGE OF AUDIO FREQUENCIES.
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123
WHAT IS THE MOST COMMON DISTANCE BETWEEN LOADING POINTS FOR D LOADING?
1.37 km (4495 FT)
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124
WHAT IS THE MOST COMMON DISTANCE BETWEEN LOADING POINTS FOR H LOADING?
1.83 km (6004 FT)
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125
WHAT TYPES OF SIGNALS ARE BLOCKED BY LOADING COILS?
ANALOG HIGH FIDELITY AND DIGITAL SIGNALS.
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126
HOW DO LOADING COILS AFFECT DATA TRANSMISSION?
LOAD COILS ADVERSELY AFFECT DATA TRANSMISSION.
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127
WHAT DETERMINES THE UPPER CUTOFF FREQUENCY OF A LOADING COIL?
LOADING COIL SPACING DETERMINES THE UPPER CUTOFF FREQUENCY.
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128
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.
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129
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.
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130
NAME 3 COMMON IMPLEMENTATION OPTIONS FOR THE IP TELEPHONY ARCHITECTURE.
1. SEPERATE 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
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131
ALTHOUGH USING A DUAL-PORT TELEPHONE OR SOFTPHONE MAY SOUND LIKE AN ATTRACTIVE OPTION, WHAT ARE THE POSSIBLE DRAWBACKS?
A SINGLE CABLE CARRYING ALL THE INFORMATION REDUCES FLEXIBILITY AND REDUNDANCY.
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132
HOW MANY TELECOMMUNICATIONS OUTLETS OR CONNECTORS ARE RECOMMNEDED FOR EACH INDIVIDUAL WORK AREA?
2
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133
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 A VOICE AND THE OTHER WITH DATA, BOTH SHOULD BE CONSIDERED CABLES THAT SUPPORT DATA APPLICATIONS.
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134
WHAT IS USED TO PROVIDE UNINTERUPTED POWER TO THE TELEPHONE SET?
POWER OVER ETHERNET (POE)
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135
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.
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136
WHAT 3 STEPS ARE USED TO CONVERT AN ANALOG SIGNAL TO A DIGITAL SIGNAL?
1. FILTERING
2. SAMPLING
3. QUANTITIZING/COMPANDING
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137
WHY IS THE ANALOG FILTERED BEFORE IT IS SAMPLED?
TO LIMIT ITS FREQUENCY CONTENT
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138
WHAT SAMPLING RATE IS USED TO FAITHFULLY REPRODUCE THE ANALOF SIGNAL DURING THE CONVERSION PROCESS?
A RATE THAT IS AT LEAST TWICE THE HIGHEST FREQUENCY COMPONENT OF THE ANALOG SIGNAL.
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139
WHAT IS QUANTIZING?
ASSIGNING EACH SAMPLED VALUE A DISRETE LEVEL THAT APPROXIMATES THE ANALOG SIGNAL AT THE SAMPLING INSTANT.
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140
WHAT IS COMPANDING?
NON-UNIFORM MAPPING BETWEEN THE ANALOG SAMPLED VALUE TO AN ASSIGNED DIGITAL LEVEL.
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141
NAME THE 2 FORMS OF COMPANDING THAT ARE IN CURRENT USE.
1. A-LAW
2. Mu-LAW
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142
WHAT TYPE OF COMPANDING IS USED IN THE UNITED STATES, CANADA AND JAPAN?
Mu-LAW
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143
WHAT TYPE OF COMPANDING IS USED IN EUROPE?
A-LAW
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144
TRUE OR FALSE A-LAW AND Mu-LAW ARE COMPATIBLE.
FALSE, ALTHOUGH THEY PERFORM SIMILAR FUNCTION, A-LAW AND Mu-LAW ARE NOT COMPATIBLE.
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145
WHAT TERM IS USED TO DESCRIBE THE THREE-STEP PROCESS FOR CONVERTING AN ANALOG SIGNAL INTO A DIGITAL SIGNAL?
PULSE CODE MODULATION (PCM)
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146
WHAT IS USED TO ENCODE SPEECH SIGNALS AT DATA RATES LOWER THAN 64 kb/s?
DATA SIGNAL PROCESSING
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147
WHAT DATA RATES CAN BE USED BY ADPCM?
40, 32, 24, AND 16 kb/s
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148
WHAT DEVICE IS USED TO CONVERT SPEECH TO A DIGITAL SIGNAL AND ITS SUBSEQUENT DECODING TO SPEECH?
CODEC
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149
AT WHAT RATES CAN VOCODERS TRANSMIT SPEECH?
8 TO 2.4 kbs
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150
WHAT DO LOWER BIT RATES TYPICALLY IMPLY ABOUT A SIGNALS QUALITY?
THAT THE SIGNAL QUALITY IS DEGRADED
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151
WHAT PROCESS INVOLVES COMBINING BINARY DATA FROM SEVERAL DIFFERENT SOURCES INTO A SINGLE COMPOSITE BIT STREAM?
TIME DIVISION MULTIPLEXING
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152
WHAT IS THE PURPOSE OF TDM?
TO INCREASE THE INFORMATION-CARRYING OF THE DIGITAL TELECOMMUNICATIONS CHANNEL.
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153
HOW IS TDM ACCOMPLISHED?
BY PREDETERMINED (DETERMINISTIC) INTERLEAVING OF SAMPLES FROM DIFFRENT VOICE CHANNELS ALONG WITH ONE OR MORE BITS FOR CONTROL PURPOSES TO MAKE UP A FRAME.
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154
WHAT IS THE MOST POPULAR FORM OF TDM?
STATISTICAL TDM
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155
IN THE DS1 FORMAT, THE DIGITAL DATA FROM _____ SPEECH CHANNELS IS COMBINED FOR TRANSMISSION OVER A SINGLE TRANSMISSION CHANNEL.
24
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156
WHAT IS THE DATA RATE FOR THE DS1 FORMAT?
1.544 Mb/s
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157
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.
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158
WHAT IS THE DATA RATE FOR THE CEPT PCM-30 FORMAT?
2.048 Mb/s
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159
WHAT TERM IS USED TO DESCRIBE THE PROCESS OF RECONSTITUTING THE INDIVIDUAL CHANNELS FROM THE COMPOSITE SIGNAL?
DEMULTIPLEXING
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160
WHAT IS A CHANNEL BANK?
MULTIPLEXING AND DEMULTIPLEXING EQUIPMENT
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161
WHAT STAGES OF MULTIPLEXING CONTAIN A/D CONVERSION?
ONLY THE FIRST ORDER MULTIPLEXING STAGE (T1 AND E1)
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162
IN THE UNITED STATES, HOW MANY T1 FRAMES ARE NEEDED TO CREATE A SUPEFRAME?
12
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163
IN EUROPE, HOW MANY E1 FRAMES ARE NEEDED TO CREATE A MULTIFRAME?
16
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164
WHAT IS THE BASIC UNIT OF DIGITAL DATA?
BIT
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165
TRUE OR FALSE
A SEQUENCE OF 1S AND 0S IS THE OPTIMUM FORMAT FOR TRANSMITTING 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.
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166
WHAT IS THE FINAL STEP IN THE ENCODING PROCESS?
THE MODIFICATION OF THE SHAPE AND PATTERN OF PULSES TO ACHIEVE MORE EFFICIENT TRANSMISSION.
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167
WHAT IS THE LINE-ENCODING TECHNIQUE DESIGNED TO DO?
1. ELIMINATE THE DC COMPONENT
2. IMPROVE TIMING RECOVERY
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168
WHAT ENCODING TECHNIQUE IS USED FOR T1 CARRIERS?
BIPOLAR ALTERNATE MARK INVERSION (AMI)
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169
WHAT TYPE OF ENCODING ALLOWS SIGNAL TRANSITION TO OCCUR IN THE MIDDLE OF EVERY BIT INTERVAL?
MANCHESTER ENCODING
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170
WHAT TERM IS USED TO DESCRIBE THE RATE AT WHICH A SIGNAL CAN CHANGE STATES?
BAUD
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171
WHAT TRANSMISSIN METHOD IS USED FOR ISDN (BASIC RATE)
2B1Q
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172
WHAT TRANSMISSION METHOD IS USED FOR ISDN (PRIMARY RATE)?
BIPOLAR
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173
WHAT TRANSMISSION METHOD IS USED FOR HDSL?
2B1Q
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174
WHAT TRANSMISSION METHOD IS USED FOR 10BASE-T?
MANCHESTER
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175
WHAT IS THE ENCODING RATE FOR ISDN (BASIC RATE)?
160 kb/s
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176
WHAT IS THE ENCODING RATE FOR ISDN (PRIMARY RATE)?
1.544 Mb/s
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177
WHAT IS THE ENCODING RATE FOR HDSL?
2X 784 kb/s
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178
WHAT IS THE ENCODING RATE FOR 10BASE-T?
10 Mb/s
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179
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.
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180
WHICH QAM SINUSOID IS THE EQUIVALENT OF A SINE WAVE?
I SIGNAL
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181
WHICH QAM SINUSOID IS THE EQUIVALENT OF A COSINE WAVE?
Q SIGNAL
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182
WHAT TYPE OF MODULATION DOES DMT USE?
MULTICARRIER MODULATION
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183
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
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184
WHICH LINE APPLICATION USES 8B/1Q4 PAM 5 ENCODING
1000BASE-T
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