CS601-DATA COMMUNICATIONMCQs (LEC 23-45)

(1) ________ is basis for all protocols.SDLC HDLC LAP LAN

(2) In ___________ protocols, bits are grouped into predefined patterns forming characters.Character-oriented Bit-oriented both a and b none of given

(3) Bit-oriented data link protocols designed for,

Full duplex and Half duplexPoint-to-point and multipointBoth a and bNone of given

(4) HDLC can be characterized by,Station typeConfigurationResponse modeAll of above

(5) HDLC differentiate between _________ types of stations.2 3 4 5

(6) HDLC differentiate between station(s).Primary stationSecondary stationCombined stationAll of above

(7) ___________ is a device in point-to-point or multipoint line configuration that has complete control of the link.Primary stationSecondary stationCombined stationNone of them

(8) A ________issue commands and a ________ issue responses.Secondary, primaryPrimary, secondaryPrimary, combineNone of above

(9) A _________station can both command and response.PrimarySecondary Combined None of them

(10) A ___________is one of a set of connected peer devices programmed to behave either as primary or as a secondary depending on the nature and direction of the transmission. Primary stationSecondary stationCombined stationNone of them

(11) Primary, secondary and combined stations can be configured in _______ ways.Two three four five

(12) Primary, secondary and combined stations can be configure in,Unbalanced configurationSymmetrical configurationBalanced configurationAll of above

(13) Which configuration is also called Master/Slave configuration.

Unbalanced configurationSymmetrical configurationBalanced configurationAll of above

(14) Unbalanced configuration can be point to point if only _____device(s) is/are involved.One Two Three Four

(15) ________can be point to point if only two devices are involved.Unbalanced configurationSymmetrical configurationBalanced configurationNone of them

(16) Each _______station on a link consist of two _________ stations, one a primary and other a secondary.Logical, physicalPhysical, logicalCombined, logicalPhysical, combined

(17) HDLC does not support balanced multipoint.TrueFalse

(18) A mode in HDLC is the relationship between two devices involve in an exchange. TrueFalse

(19) HDLC supports _________modes of communication between stations.Three Four Five Six

(20) _________device must have permission from --------------- device before transmitting.Primary, secondarySecondary, primaryLogical, physicalPhysical, logical

(21) All information from the _________ still go to the __________ and are then relayed to the other devices.Primary, secondarySecondary, primaryLogical, physicalPhysical, logical

(22) All stations are equal and therefore only _____connected in point-to-point are used.PrimarySecondary Combined None of them

(23) HDLC defines _______types of framesTwo three four five

(24) ______are used to transport user data and control information relation to user data.I-FramesS-FramesU-FramesAll of above

(25) _________ are used only to transport control information.I-FramesS-FramesU-FramesAll of above

(26) ________ are reserved for system management.I-FramesS-FramesU-Frames

All of above

(27) If address field is only 1 byte, the last bit is always 0.TrueFalse

(28) The two byte case is called Extender Mode.TrueFalse

(29) If the control field is a 0, the frame is a/an _________ I-FramesS-FramesU-FramesNone of given

(30) If the first bit is 1 and the second bit is a 0, it is S-Frame.TrueFalse

(31) If both first and second bits are 1’s, It is U-Frame.TrueFalse

(32) Information field contains the user’s data in a/an ________ and network management information in a/an _______.I-Frame, U-FrameU-Frame, S-FrameS-Frame, I-FrameNone of given

(33) S-Frame has no information field.TrueFalse

(34) It is not possible to send control information in the information field of the I-Frame along with the data.TrueFalse

(35) LAN stands for Local Area NetworkTrueFalse

(36) A ___________is a data communication system that allow a number of independent devices to communicate directly with each other in a limited geographic area.LANWANMANNone of given

(37) FDDI stands for Fiber Distributed Data Interface.True False

(38) Identify the standards of IEEE.Eithernet, Token BusEithernet, Token RingEithernet, Token Bus, Token RingNone of above

(39) Fiber Distributed Data Interface (FDDI) is not an ANSI standard.TrueFalse

(40) In 1985, the computer society of IEEE started a project called ________ to set standards to enable intercommunication between equipment from a variety of manufacturers.PROJECT 801PROJECT 802

PROJECT 803PROJECT 804

(41) Logical Link Control (LLC) is non-architecture specific.TrueFalse

(42) Strength of PROJECT 802 is not Modularity.True False

(43) _________ is the upper of data link layer and is common to all LAN protocols.MACLLCOSIIEEE

(44) LLC is the upper of _________layer and is common to all LAN protocols.PhysicalNetworkData linkSession

(45) ________contains Synchronization Flag, Flow and error control specifications as well as the physical address of next station to receive and route a packet.MACLLCOSIIEEE

(46) MAC is containing ofSynchronization FlagFlow and error control specificationsPhysical address of next station to receive and route a packetAll of above

(47) The data unit in the LLC level is called the Protocol Data Unit (PDU).TrueFalse

(48) which field(s) is/are familiar from HDLC:A destination service access pointA source service access pointAn information fieldAll of above

(49) The first bit of the DSAP indicates whether the frame is intended for an individual or a group.TrueFalse

(50) The PDU has no flag field, no CRC, and no station address.TrueFalse

(51) The word ______specifies a digital signal and word _____ specifies an analog signal.Base, broadBroad, baseBase, bandBand, broad

(52) IEEE divides the base band category into ________ standards.Three Four Five Six

(53) IEEE defines only one specification for the broad band category.10 Base 510 Base 210 Base-T10 Base 36

(54) Such overlaps which turn signals to noise are called “COLLISION”.

TrueFalse

(55) The access mechanism used in Ethernet is called CSMA/CD. TrueFalse

(56) If a system transmits after checking the line and other system transmits during this small interval, collision can still occur.TrueFalse

(57) During the data transmission, the station checks for extremely _______voltages that indicate a collision. Low high extra high extra low

(58) The NIC (Network Interface Card) usually fits inside the station and provide the station with a _____Physical address.5-byte 6-byte 7-byte 8-byte

(59) Ethernet LANs can support data rate between________1 and 100 Mbps100 and 256 Mbps1 and 1000 Mbps100 and 1000 Mbps

(60) The first of physical standards defined in IEEE 802.3 model is called ______ Thick Ethernet or Thicknet.10 Base 210 Base 510 Base 410 Base 6

(61) 10 Base 5 is a ______Topology LAN.Star Ring Bus Tree

(62) RG-8 cable is a thick coaxial cable that provides the backbone of IEEE 802.3 standard.TrueFalse

(63) The spike is attached to wires outside the transceivers.TrueFalse

(64) The second Ethernet Implementation defined by IEEE 802 series is called ______ Thin Ethernet or Thin net.10 Base 210 Base 510 Base 410 Base 6

(65) Like 10 Base 5, 10 Base 2 is a _______Topology.Star Ring Bus Tree

(66) In 10 Base 2 no AUI cables are needed.TrueFalse

(67) A ______ NIC not only provides the station with an address but also checks for voltage on the link.10 Base 210 Base 510 Base 410 Base 6

(68) These cables are relatively easy to install and moves around.AUI CablesRG-8 CablesRG-58 CablesAll of above

(69) _______ Ethernet is also called Twisted pair Ethernet.10 Base 210 Base 510 Base TNone of given

(70) 10 Base T is a ________ Topology.Star Ring Bus Tree

(71) 10 Base T support a data rate of _________Mbps and has a maximum length of _____ meters.100, 10010, 100100, 100010, 500

(72) A 4-pair UTP of not more than 100 meters connects the NIC to the appropriate in 10 Base T Hub.True False

(73) The __________of a cable and the convenience of RJ-45 jack and plug makes it the easiest to install and reinstall.WeightFlexibilityWeight & FlexibilityNone of given

(74) 1 Base 5 is also called Star LAN.True False

(75) Star LAN allow ________ devices to be linked with only the lead device connected to the Hub.10 12 15 20

(76) An attempt to improve the performance of 10 Base T is usedSwitched EthernetFast EthernetGigabit EthernetNone of given

(77) Data rate can be increased by decreasing the collision domain in ________Switched EthernetFast EthernetGigabit EthernetNone of given

(78) Token ring does not allow each station to send one frame per turn.True False

(79) Token ring imposes a time limit to keep traffic move.True False

(80) In Token ring ___________generates a new token when it is lost.Monitor stationPrimarySecondary Combined

(81) In a Ring Topology one disabled or disconnected node could stop the traffic flow around the entire network.True False

(82) One Multi Access Unit (MAU) can support up to _______ stations.4 6 8 10

(83) ___________is the name of specific world wide net work.Internet internet (with small i)

(84) Y-MODEM is similar to X-MODEM with only the following major difference(s).1024-Byte data unitTwo CANs to abort transmissionITU-T CRC-16 for error checkingAll of above

(85) Z-MODEM is not a combined feature of X-MODEM and Y-MODEM.True False

(86) BLAST is more powerful than X-MODEMTrue False

(87) BLAST has characteristics like as,Full DuplexSliding window flow controlMore powerful than X-MODEMAll of given

(88) KERMIT is most widely used Asynchronous Protocol.True False

(89) ___________of synchronous transmission makes it a better choice over Asynchronous transmission for LAN, WAN and MAN technology.EfficiencySpeedCostBit rate

(90) Synchronous Protocols can be divided into ________main classes.Two Three Four Five

(91) Character-oriented Protocol is also called as Byte-oriented Protocol.True False

(92) __________Protocols interpret a transmission frame or packet as a succession of characters, each usually composed of one byte.Character-orientedBit- orientedBoth a and bNone of given

(93) __________Protocols interpret a transmission frame or packet as a succession of individual bits, made meaningful by there placement in the frame.Character-orientedBit- orientedBoth a and bNone of given

(94) Character-oriented Protocols are as efficient as bit-oriented protocols and are seldom use.True False

(95) In all data link protocols, ___________is inserted in the data frame as separate control frame.AddressControl informationData rateCharacter

(96) Flow control is needed to prevent ____________.

Collision between sender and receiverOverflow of the receiver bufferOverflow of the sender bufferBit errors

(97) In Synchronous TDM, Time slots are not same in number as input devices.

TRUE FALSE

(98) If the primary wants to receive data, it asks the second-arise if they have anything to send, this is called POLLINGSELECTING

(99) For point-to-point configuration, addressing is needed

TRUE FALSE

(100) The Hamming code is a method of __________.

Error correctionError detectionError encapsulationError detection & error encapsulation

(101) T-Connector is used thick connector

True False

(102) _____ uses a series of filters to decompose multiplexed signal into its constituent signals.

MUXDEMUXDULEXAny of given

(102) Which error detection method involves polynomials?

Simple parity checkTwo-dimensional parity checkCRCChecksum

(104) In 56K Modems Max Uploading speed is ______ bytes and downloading speed is ______ byte.

40K, 56K33.6K, 56K56K, 33.6KNone of given

(105) Synchronous protocols are _____________ than Asynchronous protocols.

Low speedEfficientBadNone of the above

(106) Permanent analog connection between two subscribers is called. _____________.

Switched/56 serviceAnalog leased serviceDDSDS

(107) Asynchronous TDM is efficient only when the size of the time slot is kept relatively ________

LargeSmallMediumZero

(108) Modem standards are _______________.

Cable ModemBell and ITU-U ModemTraditional and 56K ModemNone of given

(109) A timer is set when ___________ is (are) sent out.

A data frameAn ACKA NAKAll of given

(110) FTTC can be implemented in ______________.

Telephone systemCable systemTelephone and cable systemNone of the above

(111) Traditional Modems are limited to a data rate of ____________.

56Kbps40Kbps33.6Kbps20Kbps

(112) Cable TV provides residential premises with a _________ cable.

Fiber opticCoaxial cableTwisted-pair cable None of above

(113) _________ can be left aside to allow a user to download and upload the information from the internet.

Two bandsThree bandsFour bandsFive bands

(114) Downloading required a ______ BW in the range above _______.

10MHz, 56MHz56MHz, 16MHz10MHz, 40MHz6MHz, 40MHz

(115) The demodulation technique used in downloading is ___________.

56QAM64QAM24QAM16QAM

(116) Currently downloading rate is between_________.

3 and 10 Mbps6 and 40Mbps12 and 56Mbps32 and 100Mbps

(117) Uploading required a ______ BW in the range above _______.

6MHz, 40MHz10MHz, 56MHz56MHz, 16MHz10MHz, 40MHz

(118) The demodulation technique used in uploading is ___________.

QAMPCMQPSKPSK

(119) If a user has a BW of 10MHz he/she can download at a rate of _______.

40Mbps50Mbps60Mbps70Mbps

(120) If a user has a BW of 10MHz he/she can upload at a rate of _______.

20Mbps30Mbps40Mbps50Mbps

(121) Currently uploading rate is between 500Kbps and 1Mbps.

TRUE FALSE

(122) Signals are transmitted from one device to another in the form of ________

Mechanical energyKinetic energyElectromagnetic energyPotential energy

(123) Chose correct statement about radio waves

It can travel through air and spaceIt required specific transmitting and receiving mechanismsBoth a and bNone of given

(124) Guided media are those media that do not provide a conduit from one device to another.

TRUE FALSE

(125) Select wrong statement for twisted pair cable.

It has two forms UTP and STPIts frequency range is 100Hz to 5MHzBasic twisted pair cable is used in Telephone systemNone of given

(126) The plastic insulation is color banded for identification.TRUE FALSE

(127) In the past, ______ flat wires were used for communication.

Two non-parallelsTwo parallelTwo verticalTwo horizontal

(128) Twisting always eliminates the impact of noise but it does not significantly reduce it.

TRUE FALSE

(129) Unshielded Twisted Pair (UTP) is _________.

CheapFlexibleEasy to installAll of above

(130) Higher grades of UTP are used in many _________.

LAN technologiesLAN technologies and EthernetEthernet and Token RingLAN technologies including Ethernet and Token Ring

(131) The most frequently used of plugs is a ____ connector with ___ conductor, one for each wire of _____ twisted pairs.

RJ45, 4, 8RJ45, 8, 4RG8, 4, 8RG8, 8, 4

(132) Chose the correct statement

Shielding each pair of twisted pair can not eliminate most crosstalkSTP is most expensive than UTPSTP is most susceptible to noiseFemale connectors snap into male connector

(133) The frequency range of Coaxial Cable is between ________.

100 KHz to 500MHz100MHz to 500MHz10MHz to 100MHz10 KHz to 100MHz

(134) Radio Government (RG) number denotes a unique set of physical specification(s), including,

The wire gauge of inner connectorThe thickness and type of inner insulatorConstruction of the shieldAll of above

(135) Radio Government (RG) used in Thick Ethernet is/areRG-8 RG-9 RG-11 All of above

(136) Radio Government (RG) used in Thin Ethernet isRG-58 RG-59 RG-28 RG-45

(137) Radio Government (RG) used for TV isRG-58 RG-59 RG-28 RG-45

(138) Most common connector is called ____________ because of its shape.

Male ConnectorFemale ConnectorBarrel ConnectorNone of the above

(139) BNC connector pushes on and locks into place with ______turn.Full Half Maximum Minimum

(140) Commonly used connectors are ______________.

T-Connector and TerminatorT-Connector and U-ConnectorTerminator and U-ConnectorX-connector and T-connector

(141) T-connector is used in Thin Ethernet.TRUE FALSE

(142) __________connector allows a secondary cable or cables to branch off from a main line.

Male connectorFemale connector

T-connectorU-connector

(143) __________are required for bus topologies.

Male connectorsTerminatorsFemale connectorsT-connectors

(144) A _________absorbs the wave at end and eliminates the echo.

Male connectorTerminatorFemale connectorT-connector

(145) Identify the wrong statement

Optical Fiber is made of glass or plasticOptical Fibers transmit signals in the form of lightThe speed of light in vacuum is 300,000 Km/secT-connector is used in Thick Ethernet

(146) Identify the correct statement

Optical Fiber is made of glass or plasticOptical Fibers transmit signals in the form of ElectromagneticT-connector is used in Thick EthernetAll of above

(147) Direction in which a light is refracted depends upon the ________ of a medium.

HeightDensityStructureQuality

(148) The incident angle at which the refracted angle is _____ degree is called Critical angle.

90604530

(149) The incident angle at which the refracted angle is 90 degree is called _________.

Vertical angleHorizontal angleCritical angleNone of above

(150) Optical fibers are used reflection to guide light through a channel.TRUE FALSE

(151) Fiber technology support _____ modes for the propagation of light.

Two Three Four Five

(152) Identify the wrong statement

Some beams travel straight and reach the destination without reflectingEach beam angle is equal to its angle of reflectionThe signals are introduced at the bottom of the coreA grade index fiber is the one with varying densities

(153) Single Mode Fiber is manufactured with a much ________ diameter than Multimode.

SmallerGreater

(154) Optical Fibers are defined by the ratio of the diameter of _____ to the diameter of ____.

Cladding, CoreCore, CladdingSource, destination Circle, Core

(155) In the Fiber type 62.5/125 the Core is ______ and Cladding is_______.

62.5, 125125, 62.50.5, 0.1062.5, 0.5

(156) Both Core and Cladding can be made of either glass or plastic but must be same densities.

TRUE FALSE

(157) The outer jacket of Optical Fiber can made of material(s)_____

TeflonFiber PlasticMetal tubingAll of above

(158) Identify the correct statement

Plastic provides structural strength Metal tubing provides strengthTeflon provide the cable strengthNone of the given

(159) Photodiode converts the light into current usable by the computer.

TRUE FALSE

(160) All of the popular connector are Barrel shaped that come in male and female versions.

TRUE FALSE

(161) The major advantages of Optical Fiber over twisted-pair and coaxial cables are____.

Noise restriction, Fragility, Higher bandwidthLess Signal Attenuation, Noise restriction, higher bandwidthNoise restriction, Fragility, Less Signal AttenuationNone of the given

(162) The disadvantage(s) of Optical Fiber is/are____.

Noise restriction, FragilityLess Signal Attenuation, Noise restrictionFragility, Less Signal AttenuationFragility

(163) Radio wave transmission utilized ________ different type of propagation.

Two Three Four Five

(164) Radio Technology considers the earth as surrounded by ___ layers of atmosphere.

Two Three Four Five

(165) The portion of the atmosphere extended outward approx. 30 miles from the earth surface is called___________

TROPOSHEREIONOSPHEREBoth a and bNone of given

(166) A signal can be directed in a straight from Antenna to Antenna is called ________

Ionosphere BroadcastLine-of-sightSpace

(167) What propagation allows greater distance to be covered?

Ionosphere BroadcastLine-of-sightSpace

(168) The type of propagation used in radio transmission depends upon the ______ of the signal.

QualityTypeFrequencyAmplitude

(169) Very Low Frequency (VLF) is used for ______ radio navigation and submarine communication.

Long-rangeShort-rangeBoth a and bNone of given

(170) The range of Very Low Frequency (VLF) is ______________.

3 KHz to 15 KHz3 KHz to 30 KHz3 KHz to 12 KHz3 KHz to 20 KHz

(171) Identify the wrong statement

VLF waves are propagated as surface waves through airLF waves are propagated as surface waves through airMF waves are propagated as surface waves through airNone of the given

(172) Which frequency type is used for AM radio?

Low FrequencyMiddle FrequencyHigh FrequencyAll of above

(173) Very High Frequency is used for___________.

VHF TelevisionFM RadioAircraft AM RadioAll of above

(174) Ultra High Frequency is used for________________.

UHF TelevisionMobile Telephone and Microwave LinkPaging and Cellular RadioAll of above

(175) Super High Frequency is used for____________

TerrestrialSatellite MicrowaveRadar CommunicationAll of above

(176) Extremely High Frequency is work in range of ______________

30 MHz – 300 MHz30 MHz – 100 MHz100 MHz – 300MHz100 MHz – 500 MHz

(177) How many types of antennas, are used for Microwave communication.

Two Three Four Five

(178) Each service area is divided into small ranges called “ CELLS”

TRUE FALSE

(179) Each cell office is controlled by a switching office is called_________.

TMSOMSTOMTSOSTMO

(180) Identify the correct option given bellow

Cell office MTSO Telephone OfficeMTSO Cell office Telephone OfficeTelephone Office Cell Office MTSONone of the given

(181) Identify the wrong statement given bellow

MTSO monitor the signal level every few secondsMTSO assigns an unused voice channelMTSO sends queries to only one cell (paging)Telephone Office sends the signals to MTSO

(182) What do you mean by Attenuation?

Loss of energyLoss of signalsLoss of linkLoss of money

(183) Negative dB mean_________ and positive dB mean_________

Attenuation, AmplificationAmplification, AttenuationAttenuation, NoiseNoise, Amplification

(184) Identify the correct statement given bellow

Distortion means that the signals change its form and shapeDistortion occur in a composite signalsBoth a and bNone of above

(185) It comes from sources like Motors and Appliances,

Induced NoiseCrosstalkImpulse NoiseAll of above

(186) Effect of one wire on other is what type of Noise?

Induced Noise Crosstalk Impulse Noise All of above

(187) Spike comes from power lines; lightening etc is what type of NOISE?

Induced NoiseCrosstalkImpulse NoiseAll of above

(188) Which concept(s) is/are used to measure the performance of the TX Media?

ThroughputPropagation SpeedPropagation TimeAll of above

(189) The propagation speed of EM signals depends on the _______ of the signals

MediumFrequencyMedium and frequencyMedium and quality

(190) If TX capacity of a link is ______ than the TX needs of a device attached to it, the excess capacity is wasted.

SmallerGreater

(191) WDM stands for

Wave Division Multiplexing Wrong Division MultiplexingWell Division Multiplexing West Division Multiplexing

(192) Multiplexing has long been used as an essential tool in ______.

Electronic industryTelephone industrySpace scienceVLAN

(193) A portion of the path that carries TX b/w a given pair of devices is known as __________.

Node Bridge Channel Access Point

(194) Multiplexing is the set of techniques that allows simultaneous TX of multiple signals across a ___________ data link

Single Double Multi None of the given

(195) There are ________ basic categories of multiplexing.

3 4 5 6(196) Amplifiers are used to __________the signal to heat.

AmplifyRectifyTestifyNullify

(196) Optical signals are multiplexed using _________ at switching office to create wider BW optical signals

WDM FDM TDM MUX

(197) HDLC is an acronym for ______________.

High-duplex line communicationHigh-level data link controlHalf-duplex digital link combinationHost double-level circuit

(197) An analog technique that can be applied when BW of a link is greater than the combined BW of the signals to be TX.

WDM FDM TDM MUX

(198) ______ uses a series of filters to decompose multiplexed signal into its constituent signals.

FDM TDM DEMUX MUX

(199) The order of receipt tells the _________ where to direct each time slot so no addressing is necessary

FDM TDM DEMUX MUX

(200) Waste of empty slots is a weakness of synchronous TDM.

TRUE False

KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK

There are how many factors on which the performance of a network depends? ► Three ► Five ► Four ► Two

_________requires the maximum number of I/O ports.

► Bus ► Star ► Mesh ► Ring

Headers are added at layers 1 and 7 of OSI model. ► True ► False

Trailer is only added at ________layer of OSI model. ► Data link ► Physical ► Network ► Application

A sine wave must be an analog signal. ► True ► False

If there is __________in voltage then the frequency is infinite. ► Instantaneous change ► Continuous change ► No change

The inversion of the level at 1 bit is called as __________ ► NRZ-L ► NRZ-I ► RZ

The last process in PCM is _________ digital data into digital signal. ► encoding

► decoding ► modulating

Amplitude in ASK is more resistive to EMI and Noise. ► True ► False

If FCC regulations are followed, the carrier frequencies of adjacent AM radio stations are ____________ apart. ► 5 KHz ► 10 KHz ► 200 KHz ► 530 KHz

In _____________ transmission, a start bit and a stop bit frame a character byte. ► Asynchronous serial ► Synchronous serial ► Parallel ► Asynchronous & Synchronous serial

Synchronous transmission has _____________.

► a start bit ► a stop bit ► gaps between bytes ► none of the given

Transmission media are usually categorized as _____________ ► Fixed or Unfixed ► Guided or Unguided ► Determinate or Indeterminate ► Metallic or Nonmetallic

The RG number gives us information about ________. ► Twisted pairs ► Coaxial cables ► Optical fibers ► all of the given

Microwave frequencies range from _________. ► 30 to 300 KHz ► 300 KHz to300 KHz to 3 GHz ► 3 KHz to 300 GHz ► 3 KHz to 3000 GHz

All of popular Fiber optic connectors are ___________ shaped. ► Conical ► Barrel ► Circular ► Rectangular

In ______________ method a signal can be directed in a straight from Antenna to antenna. ► Line of sight ► Ground propagation ► Sky propagation ► Microwaves

Amplifiers are used to __________the signal to heat. ► Amplify ► Rectify

► Testify ► NUllify

There are ________ basic categories of multiplexing. ► 3 ► 4 ► 2 ► 5

If a T-1 carries 8000 frames, the data rate is ___________ ► 2.544 Mbps ► 1.544 Mbps ► 1.544 Kbps ► 1.544 Gbps

FTTC stands for _____________ ► Flexible to the curb ► Fiber to the curb ► Fiber to the cable ► Fiber to the center

Optical signals are multiplexed using _________ at switching office to create wider BW optical signals ► WDM ► FDM ► TDM ► MUX

Which error detection method consists of a parity bit for each unit as well as an entire data unit of parity bits? ► Simple parity check ► Two-dimensional parity check ► CRC ► Checksum

If the ASCII character G is sent and the character D is received, what type of error is this? ► Single-bit ► Multiple-bit ► Burst ► Recoverable

Flow control is needed to prevent ____________ ► Bit errors ► Overflow of the sender buffer ► Overflow of the receiver buffer ► Collision between sender and receiver

In data link layer, communication requires at least ___________ devices working together ► 3 ► 2 ► 4 ► 5

Data link control is composed of ____________ important functions. ► 2 ► 3 ► 4 ► 5

Error control is both error _________ and error ___________

► Detection; correction ► Detection; deletion ► Detection; avoidance ► Detection; forwarding

ENQ/ACK stands for______________ ► Enquiry/ Acknowledgment ► Enque/ Acknowledgment ► Enquist/ Acknowledgment ► none of the given

In __________ ARQ, if a NAK is received, only the specific damaged or lost frame is retransmitted. ► Stop-and-wait ► Go-Back-N ► Selective repeat ► Stop-and-wait & Go-back-N

Sliding window requires that data frames be transmitted _______________ ► Sequentially ► Frequently ► Synchronously ► Asynchronously

Which of the following combines features of the other two? ► ZMODEM ► YMODEM ► XMODEM ► None of given

BLAST stands for : ► Blocked asynchronous transmission ► Blocked synchronous transmission ► Barrel asynchronous transmission ► Below asynchronous transmission

HDLC is an acronym for ______________.

► High-duplex line communication ► High-level data link control ► Half-duplex digital link combination ► Host double-level circuit

The HDLC ___________ field defines the beginning and end of a frame. ► Flag ► Address ► Control ► FCS

The shortest frame in HDLC protocol is usually the _________ frame. ► Information ► Supervisory ► Management ► None of the given

The PDU has no flag fields, no CRC, and no station address ► TRUE ► FALSE

_________ is the access protocol used by traditional Ethernet.

► CSMA/CD ► CSMA/CA ► Token Ring ► CSMA

Repeater is an amplifier, not a regenerator. ► True ► False

Bridges can divide a large ________ into smaller segments ► Network ► Packet ► Frame ► Address

The information to be communicated in a data communications system is the ► Medium ► Protocol ► Message ► Transmission

A set of devices connected by communication links is called networking ► True ► False

Internet with small “i” specifies the world wide Network the actual internet. ► True ► False

Data chunk at data link layer is called________ ► Frame ► Packet ► Datagram

Data synchronization is a function related with ___________ ► Session layer ► Presentation layer ► Transport

When data are transmitted from device A to device B, the header from A’s layer 4 is read by B’s __________ ► Physical ► Transport ► Application ► None of the given

Data must be converted into__________ before transmission. ► Signal ► Wave ► Electric pulse

PCM is the first process of PAM. ► True ► False

In _____________ transmission, bits are transmitted over a single wire, one at a time. ► Asynchronous serial ► Synchronous serial ► Parallel

► Asynchronous & Synchronous serial

EIA 232 allows for a maximum bit rate of __________Kbps. ► 40 ► 30 ► 20 ► 10

When a beam of light travels through media of two different densities, if the angle of incidence is greater than the critical angle, ____________occurs. ► Reflection ► Refraction ► Incidence ► Criticism

A parabolic dish antenna is a(n) ______________ antenna. ► Omni directional ► Bidirectional ► Unidirectional ► Horn

Ultra high-frequency waves always use __________ propagation. ► Ground ► Sky ► Line of Sight ► Space

Middle frequency waves having range 300 KHz-3 MHz always use __________ propagation. ► Ground ► Sky ► Line of Sight ► Space

dB is ____________ if a signal is attenuated. ► Negative ► Positive ► Null ► Zero

Which multiplexing technique involves signals composed of light beams? ► FDM ► TDM ► WDM ► none of the given

Multiplexing has long been used as an essential tool in the ____________. ► Electronic industry ► Telephone industry ► Space science ► VLAN

A telephone network is an example of a __________ network. ► Packet-switched ► Circuit-switched ► Message-switched ► None of the given

The local loop has ___________ cable that connects the subscriber telephone to the nearest end office. ► Twisted-pair

► Coaxial ► Fiber-optic ► None of the given

Which error detection method involves polynomials? ► Checksum ► Two-dimensional parity check ► CRC ► Simple parity check

In CRC there is no error if the remainder at the receiver is ____________ ► Equal to the remainder at the sender ► Zero ► Nonzero ► The quotient at the sender

In CRC the quotient at the sender _____________ ► Becomes the dividend at the receiver ► Becomes the divisor at the receiver ► is discarded ► is the remainder

Which error detection method can detect a bust error? ► The parity check ► Two-dimensional parity check ► CRC ► Two-dimensional parity check and CRC

At the CRC checker, ________ means that the data unit is damaged ► A string of 0s ► A string of 1s ► A string of alternating 1s and 0s ► A nonzero remainder

Error control is both error _________ and error ___________ ► Detection; correction ► Detection; deletion ► Detection; avoidance ► Detection; forwarding

In line discipline the initiator first transmits a frame called an ________ ► Enquiry ► Acknowledgment ► NAK ► Request

In line discipline after the data transmission, the sending system finishes with an _____________ frame ► EOT ► EKT ► ENT ► ESP

In primary-secondary communication ______________ is always the initiator of a session ► Primary ► Secondary ► Sender ► Receiver

Primary device uses ____________ to receive transmission from the secondary devices.

► ACK ► ENQ ► POLL

In a Go-Back-N ARQ, if the window size is 63, what is the range of sequence number? ► 0 to 63 ► 0 to 64 ► 1 to 63 ► 1 to 64

Sliding window requires that data frames be transmitted _______________

► Sequentially ► Frequently ► Synchronously ► Asynchronously

Data link protocols can be divided into ______________ sub-groups. ► Two ► Three ► Four ► Five

XMODEM is a ______________ protocol designed for telephone-line communication b/w PCs. ► File transfer ► Hardware ► Software ► Application exchange

In Y-MODEM Multiple files can be sent simultaneously ► True ► False

Which of the following combines features of the other two? ► ZMODEM ► YMODEM ► XMODEM ► None of given

BLAST stands for: ► Blocked asynchronous transmission ► Blocked synchronous transmission ► Barrel asynchronous transmission ► Below asynchronous transmission

Which one of the following uses full duplex operation with sliding window flow control. ► BLAST ► XMODEM ► YMODEM ► ZMODEM

HDLC is an acronym for ______________. ► High-duplex line communication ► High-level data link control ► Half-duplex digital link combination ► Host double-level circuit

The DSAP and SSAP are addresses used by _________ to identify the protocol stacks. ► LLC ► MAC

► Network

The PDU has no flag fields, no CRC, and no station address ► TRUE ► FALSE

Which of the following is a bus topology LAN that uses base band signaling and has a max? Segment length of 500 meters ► 10 Base5 ► 10 Base2 ► 100 Base2 ► 100 Base5

Token Bus has no commercial application in data communications ► True ► False

The BNC-T connector is a T-shaped device with _______ ports ► Three ► Two ► Four ► Five

_________ is the access protocol used by traditional Ethernet. ► CSMA/CD ► CSMA/CA ► Token Ring ► CSMA

When a collision is detected in a network using CSMA/CD _________ ► The frame is immediately resent ► A jam signal is sent by the station ► The back off value is set to 0 ► The back off value is decremented by 1

Like VRC, LRC and CRC, Checksum is also based on _______________. ► Redundancy ► Decimal Division ► Encryption ► Encoding

Check sum method is used for _______________ layers. ► Physical ► Application ► Transport ► Data link

Repeater works on __________ layer. ► Data Link ► Physical ► Network ► Application

When systems share a point to point link, then protocols used are called ___________ protocols. ► Direct ► Indirect ► Monolithic ► structured

_________ requires more bandwidth.

► FSK ► ASK ► PSK ► QAM