1. What is the name of the network topology in which there are bi-directional links between each possible node? a. Ring |
2. A 3600 character text file has to be transmitted by using a 1200 bps modem. How long will it take assuming that it takes 10 bits to represent one character? a. 3 seconds |
3. Which of the following is true of digital data transmission? a. Baud rate is equal to bit rate |
4. Which of the following is most suitable for regenerating digital signals? a. Amplifiers |
5. Which of the following is (are) not true of Radio waves? a. At the low frequency, they pass through obstacles |
6. Consider a hypothetical 600-baud modem using a modulation technique that requires four changes in state to send one bit. What will be the bps (bits per second) rate of the modem? a. 2400 |
7. Suppose 40 bits per Hertz can be encoded at high frequencies. What will be the data rate for 500 MHz bandwidth? a. 125Mbps |
8. What is the wavelength of a 1 MHz electromagnetic wave? a. 300 m |
9. A noiseless 4 kHz channel is sampled every 1 msec. What is the maximum data rate in bps? a. 1000 |
10. Television channels are 6MHz wide. How many bits per second can be sent if four level digital signals are used? Assume a noiseless channel. a. 12 Mbps |
11. Radio antennas often work best when the diameter of the antenna is equal to the wavelength of the radio wave. Reasonable antennas range from 1 cm to 5 meters in diameter. What frequency range does this cover? a. 30 MHz – 60 GHz |
12. Which transmission mode is used for data communication along telephone lines? a. Parallel |
13. What is the minimum number of wires required for sending data over a serial communications link? a. 1 |
14. Which of the following is (are) not true of a broadcast network? a. Have a single communication channel that is shared by all machines on the network |
15. What topology provides each device with a point-to-point connection to every other device in the network? a. Star |
16. Which physical network topology is used by the Ethernet technology? a. Star Topology |
17. Which access method is used by Ethernet protocol? a. CSMA / CD |
18. Which of the following Ethernet protocol allows devices at either end of a link segment to advertise and thus to negotiate speed of link, mode of operation etc.? a. AUI |
19. Which of the following best describes Carrier Sense Multiple Access Collision Detect (CSMA/CD)? a. Devices check the channel to make sure no signals are being sent before transmitting data |
20. Which of the following is used by modern EPABXs? a. Space Division Multiplexing |
Answers
1. d | 2. b | 3. e | 4. b | 5. b | 6. b | 7. d | 8. a | 9. a | 10. b |
11. d | 12. b | 13. b | 14. c | 15. c | 16. b | 17. a | 18. b | 19. a | 20. b |
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