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1. Redundancy means the ________a. Transmission rate of the systemb. Symbols are to be repeatedc. Time between failuresd. Time between successes
2. The digital information is contained in both theamplitude and phase of the modulated carrier.a. PSKb. FSKc. QAMd. ASK
3. The input signal is a binary digital signal and alimited number of out put phases are possible.a. PSKb. FSKc. QAMd. ASK
4. A radio channel is composed of ___VBchannels.a. 1800b. 900c. 10800d. 8064
5. What equation defines the composition of anISDN basic access line?a. 2B + Db. B + Dc. B + 2D
d. 2B + 2D
6. A digital network where voice, video, text anddata are multiplied into a single network forprocessing and are transmitted prior to use.a. Frame delayb. Asynchronous transfer mode (ATM)c. ISDNd. Synchronous digital hierarchy(SDH)
7. Non-ISDN equivalent can be connected to ISDNline by the use of ____.a. Terminal equipment
b. Terminal adapterc. Modemd. Network adaptor
8. A special voice encoder/decoder used indigitizing speech signal only isa. PCMb. PWMc. Vocoderd. PFM
9. Equation used to determine the number ofHamming bits in the hamming code.a. 2n = m+ n +1
b. 2n > m +n +1c. 2n > m +n +1d. 2n < m +n +1
10. What determine which network configuration ismost appropriate?a. Application layerb. Presentation layerc. Network layerd. Data link layer
11. Ethernet is a baseband system using CSMA/CDoperating at ____a. 10 Mbpsb. 20 Mbpsc. 30 Mbpsd. 40 Mbps
12. Use of coaxial cables in interconnectingnetworks is limited to an overall length of __.a. 1500 ftb. 1500 mc. 1500 kmd. 1500 kft
13. What identifies how the stations areinterconnected in a network?a. Topologyb. Architecturec. Topology or architecture
d. Topology and architecture
14. _______is a data communications networkdesigned to provide two-way communicationsbetween a large varieties of data communicationterminal equipment within a relatively smallgeographic areaa. Private Area networkb. Local Area Networkc. Wide area networkd. Ethernet
15. ______ is the mode of transmission in public
data network in which data are transferred fromsource to the network then to the destination inan asynchronous data formata. Synchronous modeb. Start/stop modec. Packet moded. Circuit mode
16. A seven digit character can represent oneof______ possibilities.a. 7b. 14c. 64
d. 128
17. ______ is defined to be the maximum rate atwhich information can be transmitted through achannel.a. Bit rateb. Baud ratec. Codingd. Channel capacity
18. Who developed the fixed-length binary code fortelegraphy?a. Samuel Morseb. Emile Baudot
c. Alexander Graham Belld. Guglielmo Marconi
19. Inventor of pulse-code modulation for the digitalencoding of speech signals.a. R.V.L. Hartleyb. J.R. carsonc. H. Nyquistd. Alex Reeves
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20. Serial binary data interchange between DTE andDCE at rates up to 20 kbps. RS 232 is its EIAequivalent.a. V.26b. V.24
c. V.42d. V.32
21. RS 232 is normally an interface between DTEand DCE. What is its signal rate?a. 20 kbpsb. 30 kbpsc. 40 kbpsd. 50 kbps
22. What is multiplexing?a. The process of increasing bandwidth on a
channelb. A technique that enables more than one
data source to share the use of acommon line
c. Mailing letter at the post officed. The ability to share frequency by time
23. In ____ modulation the carrier is a periodic trainpulses.a. Amplitudeb. Analogc. Digitald. Pulse
24. Which of the following pulse modulation
techniques is a digital transmission system?a. Pulse duration modulationb. Pulse position modulationc. Pulse width modulationd. Pulse code modulation
25. A process where the higher amplitude analogsignals are compressed prior to transmissionthen expanded at the receiver.a. Compressingb. Expandingc. Encodingd. Companding
26. _______uses a single bit PCM code to achievea digital transmission of analog signala. Quadrature Amplitude Modulationb. Frequency Shift Keying(FSK)c. Delta Modulation(DM)d. Phase Modulation(PM)
27. The line speed of bell system T1 carrier system isa. 64 kbpsb. 3.152 Mbpsc. 1.544 Mbpsd. 6.312 Mbps
28. How many channels does a super group have?a. 60b. 600c. 1800d. 10800
29. The output frequency at the channel combiner ofchannel 7 isa. 76 80 kHzb. 80 84 kHz
c. 84 88 kHzd. 88 92 kHz
30. ________was the first fixed length 5-bitcharacter code.
a. EBCDICb. ASCIIc. Morse coded. Baudot code
31. Amplitude shift keying is also known as ______.a. Up/down keyingb. On/off keyingc. Front/back keyingd. I/O keying
32. PCM system require_________.a. Analog signalb. Large bandwidthc. Digital signalsd. Fiber optics cable
33. Which theorem sets the limit on the maximumcapacity of a channel with a given noise level?a. Nyquist theoremb. Hartley theoremc. Shannon-Hartley theoremd. Shannon theorem
34. _______is the difference between the originaland reconstructed signal.a. Quantizing noiseb. Fade margin
c. Noise margind. Noise figure
35. What are the steps to follow to produce a PCMsignal?a. Sampling,coding and quantizingb. Sampling,quantizing and codingc. Quantizing,sampling and codingd. Coding, quantizing and sampling
36. ________ identifies how the different stations ina multipoint system are interconnected.a. Network topology
b. Star networkc. Ring topologyd. Bus network
37. A transmission where data are inputted directlyon the cable.a. Broadbandb. Base bandc. Digitald. Analog
38. Synchronous modems cost more thanasynchronous modems becausea. They are larger b. They must contain clock recovery
circuitsc. The production volume is larger d. They must operate on a larger
bandwidth
39. When one station is designated as master andthe rest of the stations are considered slaves,message handling is _______.a. store and forward
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b. pollingc. CSMA/CDd. Token passing
40. A store and forward switching.a. Circuit switchingb. Packet switchingc. Message switchingd. PSTN
41. A timing signal generated by an oscillating circuitthat is used to synchronize data transmission.a. Clockb. Start bitc. Quantizingd. BCC
42. Which system allows different types of networksto be linked together?
a. OSIb. CCITTc. Bell Systemd. AT & T
43. A _____ that interconnects LAN having identicalprotocols at the physical and data link layers.a. Bridgeb. Router c. Gatewayd. Hub
44. A _____ that interconnects LAN that has totally
different protocols and formata. Bridgeb. Router c. Gatewayd. Hub
45. All bits in a character can be sent/receivedsimultaneously.a. Serial datab. Parallel datac. Full duplexd. Half duplex
46. A system that perform parallel-to-seriesconversion of a data link.a. DTEb. DCEc. Modemd. FEP
47. Which mode of transmission achieves less thanfull-duplex but more than half-duplex.a. Full/full duplexb. Echoplexc. Isochronousd. synchronous
48. Rules governing the transmission of digitalinformation.a. Data communications standardb. Line protocolc. Isochronousd. Digital communications
49. Codes must bea. Eight bits per characterb. Either seven or eight bits per character
c. Agreed upon in advance between senderand receiver
d. The same in all modem computers
50. Clear to send is a signal passed from the localmodem to the local terminal when data port isready to transmit data. It usually occurs inresponse toa. Data set readyb. Request to sendc. Data terminal readyd. Data carrier detect
51. Digital to analog converter in synchronousmodems send signals to thea. Modulatorb. Transmission linesc. Terminald. equalizer
52. What is the data rate of the ISDN Basic access
B channel?a. 32 kbpsb. 64 kbpsc. 144 kbpsd. 192 kbps
53. How many bits are there to present 8combinations?a. 3b. 4
c. 2d. 5
54. How many number of equiprobable events arethere for 8-bits of information?a. 256b. 132c. 2400d. 512
55. Which character code is used without parity bit?a. CCITT number 2b. ASCCII
c. CCITT number 5d. EBCDIC
56. The percentage of bit errors relative to a specificnumber of bits received; usually expressed as anumber referenced to a power of ten.a. Bit error rateb. Transmission ratec. Distortiond. Parity check
57. The process of one type of device imitatinganother via a hardware/software package.a. Conversion
b. Emulationc. Imitationd. Simultation
58. A digital modulation technique that results in twodifferent frequencies representing binary 1 and0.a. FSKb. QPSKc. ASKd. DPSK
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59. One dit is equal to _____ bits.a. 3b. 3.5c. 3.32
d. 4
60. A quadratic signaling has _____ possible states.a. 16b. 4c. 8d. 32
61. What is the smallest unit of information in binarytransmission system?a. Byteb. Digitc. Bitd. Nibble
62. The lowest layer in the ISO protocol hierarchy.a. network layer b. physical layer c. transport layed. datalink layer
63. Modem is referred to asa. Universal asynchronous receiver transmitterb. Universal synchronous receiver transmitterc. Data terminal equipmentd. Data communication equipment
64. A signaling method relating to a multiplicity ofcircuits is conveyed over a single channel bylabeled messages.a. code signalingb. syncronousc. common channel signalingd. asynchronous
65. ______ is a network operating system withinseveral buildings in compound.a. Internetb. Novell netwarec. 10BASE-t
d. intranet
66. What is the Nyquist sample rate for a voice inputof 10 kHz?a. 10 kHzb. 20 kHzc. 30 kHzd. 40 kHz
67. What is the minimum number of bits required inPCM code for a range of 10,000?a. 12b. 9c. 14d. 8
68. How many levels can be represented in PCMtransmission system if the binary numbers00000000 to11111111 are used to representsignal levels?a. 256b. 64c. 128d. 512
69. A symbol to represent a data communicationsfacility within the wide area network.a. Hubb. Cloud
c. Server d. Gateway
70. All bits in a character are sent and received_____ in serial port.a. One at a timeb. Simultaneouslyc. In group of 2 bitsd. In group of 3 bits
71. Message switching is ____ network.a. Hold and forwardb. Forwardc. Holdd. Store and forward
72. Packet switching is _____ networka. Hold and forwardb. Forwardc. Holdd. Store and forward
73. Polling is an invitation by the primary tosecondary equipment to ____ a message.a. Storeb. Receivec. Transmit
d. Read
74. An 8-bit character code.a. EBCDICb. BAUDOTc. ASCIId. HOLLERITH
75. Equipment that interfaces the data terminalequipment to the analog transmission line.a. Modemb. Muldemc. Multiplexer
d. Codec
76. A communication network design for transferringdata from one point to anothera. Public Telephone networkb. Public Data networkc. Value Added Networkd. Packet Switching network
77. A conceptual network in which all transmissionlines handle digital or digitalized data.a. LANb. WANc. ISDNd. PSTN
78. A data communications component thatprovides control or supporting services for othercomputers, terminals, or devices in a network.a. Hostb. Communication controllerc. Cluster controllerd. Interface equipment
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79. Which data network configuration let computersshare their resources?a. Peer to peerb. Hierarchicalc. PVCd. LAN
80. A means of improving the quality of a private-line circuit by adding amplifiers and equalizer toit.a. Line equalizerb. Line amplifyingc. Line conditioningd. Line encoding
81. Direct distance dialing (DDD) network iscommonly calleda. Private-line networkb. PT network
c. Dial-up networkd. Trunk network
82. A type of server that allows multiple users totake advantage of a single printing device.a. Printb. Clientc. Networkd. File
83. _____ ensures that the transmitter and thereceiver agree on a prescribed time slot for theoccurrence of a bit.
a. Bit or clock synchronizationb. Modem or carrier synchronizationc. Character synchronizationd. Message synchronization
84. Characters that must be transmitted other thandata are calleda. Parityb. Error c. Overheadd. Hamming bits
85. The generating power polynomial x7 + x5 + x4 + x2
+ x
1
+ x is equivalenta. 101101110b. 101101111c. 010010001d. 10110111
86. A central device into which each node of a starnetwork is directly connecteda. Hubb. Central pointerc. Router d. Repeater
87. To ____ is to send a file to a remote computer.
a. Uploadb. Downloadc. Calld. Transmit
88. A microcomputer attached to a network requiresaa. NICb. RS 232c. Softwared. Protocol
89. Digital telephones and integrated voice-dataworkstations are examples of what type of ISDNequipment?a. TEb. TAc. NT2d. TP
90. How many OSI layers are covered under theX.25 standard?a. 3b. 4c. 7d. 2
91. With _____, a station monitors the line todetermine if the line is busy.a. CSMA/CD
b. CSMA/CAc. Token Passingd. PDDI
92. CCITT standard concentrating on datacommunications over the telephone network.a. V seriesb. X seriesc. I seriesd. T series
93. Broadband usesa. TDM
b. Space multiplexingc. FDMd. Statistical multiplexing
94. _____ uses the connecting medium as a single-channel device.a. Broadband transmissionb. Digital transmissionc. Base band transmissiond. Analog transmission
95. Which is considered as the fastest LANtopology?
a. Ringb. Busc. Star d. Tree
96. What is the most widely used datacommunications code?a. Grayb. EBCDICc. Baudotd. ASCII
97. Mark and space refer respectively toa. 1 and 0
b. Dot and dashc. Message and intervald. On and off
98. What is the other name for parity?a. BCCb. LRCc. VRCd. CRC
99. A device that performs routing functions andprotocol translation from one network to another.
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a. Gatewayb. Bridgec. Router d. Repeater
100. Not important characteristic of the physicallayera. Electricalb. Mechanicalc. Logicald. All of them
.
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