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Data Communication & Computer Networking

Published on May 2018 | Categories: Documents | Downloads: 6 | Comments: 0




1. The information used in the data communication belongs to a. Only analog data(voice, video) b. Only digital data(text) c. Both analog and digital data d. None 2. The fundamental purpose of a communication system is a. Signal transmitting b. Exchange of data between two parties. c. either a or b d. None 3. Select the true statements i. Destination takes the incoming data from the receiver. ii. Source device transmits the data. iii. Synchronization is the important task   performed in data communication iv. Network management capabilities are needed to configure the system, monitor its status, and plan intelligently for future growth. a. All the above c. i, iii, iv

b. i, ii, iv d. Only iv

4. In data communication _______waves are used as a means of to transmit data. a. Electromagnetic wave b. Electrostatic wave c. Electric wave d. None 5. A continuous signal might represent represent  ______and discrete signal might represent______  a. Video and Audio b. Speech and binary 1s,0s c. Binary 1s, 0s and Speech d. either b or c 6. The speed of light in free space is  b. 3 x 108 cm/s a. 3 x 10 8 m/s c. 4 x 108 inch/s d. 3 x 108 mm/s ii. Delay distortion iii. Noise

7. The relationship between data rate and  bandwidth is a. The higher the data rate of a signal, the greater  is its effective bandwidth. b. The greater the bandwidth band width of a transmission system, higher is the data rate that can be transmitted over that system c. Higher the center frequency, the higher the  potential bandwidth. d. All the above

8. _______is the physical propagation of the signal along a suitable medium. a. Data b. Transmission d. Both a & c c. Signaling 9. _______is the communication of data by the  propagation and processing of signals b. Transmission a. Data c. Signaling d. Both a & b 10. IRA stands for  a. International Reference Alphabet b. International Reference Application c. International Referring Alphabet d. None 11. The standard spectrum for a voice channel is a. 300 to 3400hz  b. 340 to 3000hz c. 300 to 4000hz d. 300 to 400hz 12. ____converts the incoming acoustic voice signal into an electromagnetic signal over the range of 300 to 3400hz. a. Transmitter  b. Telephone transmitter c. Receiver d. None

13. The device which recovers digital data from the analog signal and generates a new, clean analog signal is a. Repeater b. Transmitter  c. Attenuator d. None 14. Match the following i. Attenuation c. Unshielded Twin Pair 

d. None a. Delay distortion is a phenomenon peculiar  to guided transmission media. b. The undesired signals c. The undesired signal falls off with distance. a. i-a, ii-b, iii-c c. i-a, ii-c, iii-b

21. Optical fibers are used in a. Long distance  b. Short distance c. either a or b d. None

22. Select the true statements i. Long-haul routes average about 1500kms in length and offer high capacity 15. Select the false statements ii. Rural exchange trunks have circuit lengths i. Thermal noise is due to thermal agitation of  ranging from 50 to 200kms and link towns and  photons villages. ii. Intermodulation noise may be resulted iii. The most common type of microwave antenna when signals at different frequencies share the is the parabolic dish. same transmission medium. iv. Subscriber loop circuits are fibers that run iii. Crosstalk is wanted a coupling between directly from the central exchange to a subscriber. signal paths. a. i, ii, iii b. i, iii a. i & iii c. i, iii & iv b. All the above d. i, iv c. i & ii d. None 23. Say true or false 16. Nyquist Bandwidth is i. Broadcast Radio is omnidirectional a. B b. 2B c. 1/2B d. 3B ii. Microwave is directional iii. VSAT stands for Very Small Aperture Term 17. The maximum channel capacity in bps, as iv. The atmosphere and and outer sp space ar are  per Shannon obeys the equation_____  examples of guided media. a. C=2Blog10(M) a. T F T F b. T T T T b. C=Blog2(1+SNR) c. T T F F c. C=Blog10(1+SNR) d. F T T F d. None of the above 24. The specimen specimen frequency range for satellite 18. _______is the physical path between transmission is a. 1 to 10 Ghz transmitter and receiver. b. Up to 500Mhz c. 30 Mhz to 1 Ghz d. None of these a. Transmission medium b. Transmitter medium c. Transaction Medium 25. The satellite receives transmission on ____  d. Transaction Model a. Uplink frequency band b. Downlink frequency band 19. Unguided media media is referred to as c. Transponder band a. Cable communication d. None of these b. Wireless communication c. either a or b 26. A communication satellite is a _____relay d. None station. a. Optical b. Ratio frequency 20. UTP stands for  c. Microwave d. None a. Unshielded Twisted Pare 27. The different twist lengths in adjacent pairs b. Unshielded Twisted Pair reduces c. Hum noise d. None a. Low-frequency interference b. cross-talk  b. i-c, ii-a, iii-b d. None

28. The ______frequencies are suitable for   point-to-point wireless transmission. transmission. a. Broad cast radio b. Microwave c. Extremely high d. Voice 29. Following is the least expensive commonly used guided transmission media. a. Twisted Pair b. Coaxial Cable c. Optical fiber d. VSAT media 30. The LANs in new office buildings are  preconstructed with a UTP, which is a datagrade cable that support data rate up to 100Mbps. a. Category 3 b. Category 4 c. Category 5 d. None of the above 31. The following guided transmission media will support data rates of hundreds of Gbps over tens of kilometers. a. Coaxial cable  b. Unshielded twisted pair  c. Shielded twisted pair  d. Optic fiber  32. A device which converts digital data to an analog signal a. Modulator  b. modem c. Demodulator d. None 33. The basic techniques used for converting data are a. ASK b. FSK  c. PSK  d. All the above 34. _____are popular techniques for data transmission. b. IEEE a. Biphase codes c. ASCII codes d. None

c. PSK 

d. All the above

37. Select the true statements i. FSK is less susceptible to error than ASK. ii. Pulse code modulation is based on Sampling Theorem iii.The PCM scheme is refined using a technique known as “nonlinear encoding” iv. The modes of data transmission are Simple & half-Duplex. a. TTTT c. TTTF


38. The cost-effective method to improve the SNR ratio is _______  a. Uniform quantizing b. Nonlinear encoding c. Increasing number of quantization levels d. Increasing the number of bits b its used in encoding 39. Satellite communication channels involve relatively long transmission delays and hence, mostly use the _______mode of data transmission a. Simplex mode b. Half-duplex system c. full-duplex system d. both (a) & (b) 40. The______decrases bit error rate a. increase in data rate b. increase in bandwidth c. increase in SNR  d. None of these

41. The delta Modulation δ must be chosen to  produce a balance between following two types of  errors: a. Quantization noise and slope overload noise 35. A coding scheme that is commonly used in b. Delta error and Beta error   North America is known as c. Quantization and companding error  d. Synchronization and Pulse spreading error  a. Bipolar with 8 zeros substitution b. Bipolar with 4 zeros substitution c. Bipolar with 2 zeros substitution 42. In the _____code, there is a transition at the d. None middle of each bit period. a. Bipolar AMI 36. ________technique is used to transmit b. NRZ code digital data over optical fiber. c. Manchester  a. ASK b. FSK  d. Differential Manchester 

43. Thus digital data at a user’s terminal may  be converted to analog and subsequently digitized by a _______  a. Modem b. codec c. Decoder d. USART

ii. Use e-mail for internal communications, inter  office notes etc, creating an almost paper less office. iii. Can not share a single copy of a file among all the users, even simultaneously.

44. For a color TV signal occupying bandwidth b. Only ii a. i & ii of 4.6MHz, the PCM scheme using 10-bit c. All the above d. ii & iii coding implies a data rate of_______  a. 92 Mbps b. 56 Kbps 50. A layer of software on the top of the operating c. 128 Kbps d. 46 Mbps system is called as a. Middleware b. Topware 45. Indicate the false statement c. either a or b d. None a. FSK is less susceptible to error than ASK  b. Parallel transmission speed is much higher  51. The most essential components of a simple than serial transmission network are c. Error correction can be achieved by a. Servers b. Workstations transmission of additional bits such as c. Network Interface card d. All the above checksum, CRC or FEC d. The principal advantage of DM over PCM 52. The collection of routers and communication is the better SNR characteristic at the same lines form the _____  data rate. a. Ethernet b. Subnet c. LAN d. Piconet 46. Indicate the true statement. a. With TDM, there is an intermodulation 53. Network operating system is a noise a. Hardware b. Software b. In DM, when the analog waveform is c. Computer itself d. None of the above changing more slowly than the staircase waveform, there is slope overload noise. 54. Select the false statements c. For the telephone network, modems are a. Computers in a LAN are generally connected used to convert digital data in to analog signals through cables in the voice frequency range and vice versa. b. Print servers provide print facility to all the d. FSK is more susceptible to error than ASK  computers connected in a network  c. It is not possible to share a CD-ROM in a 47. The modulation rate is expressed in____  network  a. bps b. bauds d. The servers should be a faster computer  c. Mbps d. None of these compared to the nodes 48. If R data rate in bps, b ps, b is the number of bits  per signal element then the modulation rate D  baud is given by______  a. D=R.b b. D=R  b c. D=R.b+1 d. None of these 49. Select the statements which a networked computer can do, which a stand-alone computer cannot do i. Share resources like printers, hard disks, CD-ROM drives, modems, fax machines etc.

55. Following is not the component of a computer  network  a. Server b. World Wide Web c. Dumb terminals d. Network Operating System 56. Some companies interconnect all their  existing internal networks, often using the same technology as the internet. These are called as____  a. Ethernets b. Subnets c. Intranets d. WAN

57. Point-to-point transmission with one sender  Cards each with multiple inputs. and one receiver is sometimes called as_____  d. The hubs examine the various addresses and a. Unicasting b. Broadcast links use them in any way. c. Point-to-point links d. None 64. The planning for the network implementation 58. Using the ______program, users can copy consists of  files from one machine on the internet to a. Location plan b. Cabling plan another. c. Cable laying plan d. All the above a. FTP b. E-mail c. ARPANET d. ISP 65. Match the following i. Location Plan 59. The ________is a connection oriented ii. Cabling Plan network with no error control and, no flow iii. Cable laying Plan control a. X.25 b. Frame relay a. It affects the quality of data traffic on the cables c. ATM d. OSI and also budget.  b. The network cabling is kept away from the 60. The _________topology is most widely electrical wiring by at least 1 foot used for networking of computers. c. Deciding the exact location of server, a. Linear bus b. Ring workstations and all other terminals c. Star d. Delta b. i-c, ii-a, iii-b a. i-a, ii-b, iii-c 61. Which of the below given is a false c. i-c, ii-b, iii-a d. i- a, ii-c, iii-b statement? a. Twisting the cable reduces the electrical 66. The firewall may consist of following interference affecting the cable a. Public key b. Private RSA key b. Even though the fiber optic cables are c. Two routers and an application gateway  better compared to other type, they are d. Stackable hubs expensive and they need specialized connectors to connect to the network Interface 67. The ________preserve the order of the plain Card. text symbols but disguise them c. Using the telnet program, users can copy co py a. Substitution ciphers files from one machine on the internet to b. Transposition ciphers another. c. One-time pads d. Routers are different from repeaters, hubs, d. None of these  bridges and switches. 68. The following is the widely used secure e62. These connect two computers that use mail system different connection-oriented transport a. Secure/MIME b. AES  protocols. c. Rjndael d. DES a. Bridges b. Switches c. Routers d. Gateways 69. The ______are (is) used to prevent any outsider from cracking into the intranet. 63. The following is the description of hubs. a. Web server  a. These are analog devices that are connected  b. Software firewalls to two cable segments to amplify the signal c. Network interface card appearing on them. d. Daisy-chained hub and T-connector  b. They do not understand frames, packets, or  headers, but understand volts. 70. E-mail application works in the ______layer. c. Hubs are designed to hold h old multiple line a. Application b. Presentation

c. Transport

d. Session

71. The number of layers in a TCP/IP model is___________  a. 4 b. 5 c. 6 d. 7 72. The layer responsible for providing error  free transmission is_____________  a. Session layer b. Transport layer  c. Data link layer d. Physical layer  73. The OSI reference model has _____layers a. 5 b. 6 c. 7 d. 9 74. Indicate the true statements a. The decryption is the process of changing intelligible data into unintelligible data. b. In columnar transposition, the message is rearranged with the aid of some type of  geometric figure. c. The cryptography deals with breaking the cipher. d. The cryptanalyst knows encryption and decryption algorithms and the secrecy lies exclusively with key. 75. SLIP stands for  a. Serial Line Internet Process b. Serial Line Internet Protocol c. Serial Link Internet Protocol d. Serial Line Integration Protocol

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