Introduction to Computer Networks Answer Key Part 2

11. Because of its good shielding properties, ____ is good at carrying analog signals with a wide range of frequencies. a. CAT 1 wire c. copper wire b. CAT 2 wire d. coaxial cable ANS: D 12. ____ technology uses digital signaling in which the cable carries only one channel of digital data. a. Broadband coaxial c. Baseband coaxial b. CAT 7 d. Fiber optic ANS: C 13. ____ technology typically transmits analog signals and is capable of supporting multiple channels of data simultaneously. a. Broadband coaxial c. Baseband coaxial b. CAT 7 d. Fiber optic ANS: A 14. ____ cable ranges in size from approximately 6 to 10 mm or more (1/4 to 3/8 inch) in diameter. a. Thin coaxial c. CAT 2 b. Thick coaxial d. CAT 3 ANS: B a. b. 15. ____ cable is approximately 4 mm (less than 1/4 inch) in diameter. CAT 2 c. Thin coaxial Thick coaxial d. CAT 3 ANS: C 16. ____ cable contains, as the name implies, a single copper wire in the center of the cable. a. Braided coaxial c. thin-stranded coaxial b. Fiber optic d. Single-stranded coaxial ANS: D 17. ____ cable is a thin glass cable, a little thicker than a human hair, surrounded by a plastic coating. a. Single-stranded coaxial c. Braided coaxial b. Fiber-optic d. CAT 7 ANS: B a. 18. ____ cable is virtually impossible to wiretap. CAT 1 c. Thick coaxial b. Single-stranded coaxial d. Fiber-optic ANS: D 19. ____. a. EMI b. RFI As the length of a glass cable grows, the light signal attenuates due to reflection and c. d. refraction friction ANS: C 20. The ____ cable is similar to fiber-optic cable in that it is as thin as a hair and transparent. The big difference, however, is that this new cable is full of holes. a. photonic fiber c. thick coaxial b. single-stranded coaxial d. thin coaxial ANS: A 21. When a light signal inside the cable bounces off the cable wall and back into the cable, this is called ____. a. refraction c. blinking b. reflection d. friction ANS: B 22. ____ transmission requires the use of a very thin fiber-optic cable and a very focused light source, such as a laser. a. Multimode c. Single-mode b. Reflection d. Refraction ANS: C 23. ____ transmission uses a slightly thicker fiber cable and an unfocused light source, such as an LED. a. Multimode c. Single-mode b. Reflection d. Refraction ANS: A 24. ____ transmission systems transmit tightly focused beams of radio signals from one ground-based microwave transmission antenna to another. a. Satellite c. Downlink b. Cellular d. Terrestrial microwave ANS: D 25. ____ transmission means that to receive and transmit a signal, each antenna must be in sight of the next antenna. a. Uplink c. Line-of-sight b. Omnidirectional d. Downlink ANS: C 26. miles. The typical maximum distance between microwave towers is roughly ____ to 30 a. b. 3 6 c. d. 8 15 ANS: D 27. ____ transmission systems are similar to terrestrial microwave systems except that the signal travels from a ground station on Earth to a satellite and back to another ground station on Earth. a. Satellite microwave c. Downlink b. Cellular d. Terrestrial microwave ANS: A 28. The closer a satellite is to the Earth, the shorter the times required to send data to the satellite, that is, to ____. a. downlink c. download b. uplink d. send down ANS: B 29. The transmission time from when a signal first leaves a satellite and then arrives at a ground station is called ____. a. propagation delay c. uplink b. downlink d. upload ANS: A a. b. 30. ____ satellites are closest to the Earth. Low-Earth-orbit (LEO) c. Middle-Earth-orbit (MEO) d. Geosynchronous-Earth-orbit (GEO) Highly-elliptical-Earth-orbit (HEO) ANS: A a. b. 31. ____ satellites can be found roughly 1000 to 3000 miles from the Earth. Low-Earth-orbit (LEO) c. Geosynchronous-Earth-orbit (GEO) Middle-Earth-orbit (MEO) d. Highly-elliptical-Earth-orbit (HEO) ANS: B 32. A satellite system that has unique properties is the ____ satellite, which is used by governments for spying and by scientific agencies for observing celestial bodies. a. Low-Earth-orbit (LEO) c. Geosynchronous-Earth-orbit (GEO) b. Middle-Earth-orbit (MEO) d. Highly-elliptical-Earth-orbit (HEO) ANS: D 33. Cells, in a cellular telephone system, can range in size from one-half mile in radius to ____ miles in radius. a. 25 c. 50 b. 35 d. 70 ANS: C a. b. 34. ____ was the first-generation cellular telephone system. Personal Communications Services (PCS) Time Division Multiple Access (TDMA) c. d. Advanced Mobile Phone Service (AMPS) Global System for Mobile (GSM) Communications ANS: C 35. The ____ system is an example of a single-user Earth station satellite system with its own ground station and a small antenna (two to six feet across). a. T1 c. VSAT b. LEO d. SAT-V ANS: C a. b. c. d. 36. The first PCS technology used a form of time division multiplexing called ____. Code Division Multiple Access (CDMA) Time Division Multiple Access (TDMA) Global System for Mobile (GSM) Communications Digital-Advanced Mobile Phone Service (D-AMPS) ANS: B 37. The third PCS technology was ____ and used a different form of time division multiple access technology. a. Global System for Mobile (GSM) Communications b. Time Division Multiple Access (TDMA) c. Code Division Multiple Access (CDMA) d. Digital-Advanced Mobile Phone Service (D-AMPS) ANS: A 38. ____ is a broadband wireless transmission technology that is based upon a series of IEEE standards. a. WiFi c. IrDA b. Bluetooth d. WiMAX ANS: D 39. ____ systems transmit data over a wide range of frequencies rather than limiting transmissions to a narrow, fixed band of frequencies. a. WiFi c. Ultra-wideband b. Bluetooth d. Free space optics ANS: C a. b. 40. ____ systems are good at sending low-speed signals over short to medium distances. Microwave c. WiFi Satellite d. ZigBee ANS: D 41. The popular GPS devices that people use to find directions while driving use which type of satellite system? a. LEO c. GEO b. MEO d. HEO ANS: B a. b. 42. LEO MEO Which type of satellite remains located over the same point of earth at all times? c. GEO d. HEO ANS: C Chapter 4: Making Connections MULTIPLE CHOICE a. b. 1. The connection to a peripheral is often called the ____. USB c. FireWire interface d. EIA-232F ANS: B 2. An interface standard can consist of four parts, or components, all of which reside at the ____ layer. a. network c. physical b. data link d. transport ANS: C 3. An interface standard can consist of four parts, or components: the electrical component, the mechanical component, the ____ component, and the procedural component. a. functional c. administrative b. automatic d. organizational ANS: A 4. The ____ component of an interface deals with items such as the connector or plug description. a. administrative c. procedural b. functional d. mechanical ANS: D 5. The ____ component of an interface describes how the particular circuits are used to perform an operation. a. electrical c. procedural b. functional d. mechanical ANS: C 6. In modem interfacing terminology, the computer (or terminal) end of an interface is referred to as ____. a. data communicating equipment (DCE) c. data transmitting equipment (DTE) b. data terminating equipment (DTE) d. data receiving equipment (DRE) ANS: B a. 7. In modem interfacing terminology, the modem is referred to as the ____. data communicating equipment (DCE) c. data transmitting equipment (DTE) b. data terminating equipment (DTE) d. data receiving equipment (DRE) ANS: A 8. To define functional and procedural components, EIA-232F incorporates the ITUÕs ____ standard. a. ISO 2110 c. RS-232 b. V.28 d. V.24 ANS: D 9. time. a. b. A ____ connection is one in which both sender and receiver may transmit at the same full-duplex half-duplex c. d. single-duplex multi-duplex ANS: A 10. Some systems, for various reasons, allow only one side or the other to transmit at one time. This type of connection is an example of a ____ connection. a. full-duplex c. single-duplex b. half-duplex d. multi-duplex ANS: B 11. The idea behind ____ is that the peripheral can simply be plugged in and turned on, and that the computer should dynamically recognize the device and establish the interface. a. RS-232 c. daisy-chaining b. EIA-232F d. hot plugging ANS: D 12. The ____ component of USB strictly specifies the exact dimensions of the interfaceÕs connectors and cabling. a. procedural c. mechanical b. functional d. electrical ANS: C a. b. 13. pin bus A(n) ____ is simply a high-speed connection to which multiple devices can attach. c. circuit d. interface ANS: B 14. FireWire supports two types of data connections: an asynchronous connection and a(n) ____ connection. a. synchronous c. parallel b. timed d. isochronous ANS: D 15. ____ is a technique for interfacing a computer to high-speed devices such as hard disk drives, tape drives, CDs, and DVDs. a. Serial c. SCSI b. RS-232 d. EIA-232F ANS: C a. b. 16. SCSI is a ____ interface and not just an interface technique for hard disk drives. systems c. server terminal d. driver ANS: A a. b. 17. 2 4 You can connect up to ____ different SCSI devices to one SCSI adapter. c. 6 d. 7 ANS: D 18. time. a. b. ____ is a serial connection or bus that can carry multiple channels of data at the same InfiniBand Fibre Channel c. d. SCSI USB ANS: A a. b. 19. InfiniBand can support data transfer speeds of ____ per second. 1.5 billion bits (1.5 gigabits) c. 5 billion bits (5 gigabits) 2.5 billion bits (2.5 gigabits) d. 10 billion bits (10 gigabits) ANS: D 20. InfiniBand can address (interconnect) ____ of devices, using both copper wire and fiber-optic cables. a. tens c. thousands b. hundreds d. millions ANS: C a. b. 21. 56 126 Fibre Channel can support the interconnection of up to ____ devices only. c. 256 d. 512 ANS: B 22. To prepare a data character for transmission, a ____ bit is added to the beginning of the character and informs the receiver that an incoming data frame is arriving. a. start c. end b. stop d. parity ANS: A 23. At the end of the data character, one or two ____ bits are added to signal the end of the frame. a. start c. check b. parity d. stop ANS: D a. b. 24. With a(n) ____ connection, the unit of transmission is a sequence of characters. asynchronous c. synchronous parity d. serial ANS: C 25. A direct connection between a terminal and a mainframe computer is a ____ connection. a. multipoint c. single-point b. point-to-point d. direct-point ANS: B a. b. 26. During the early years of computing, a mainframe computer was called the ____. secondary c. dumb end terminal d. primary ANS: D a. b. 27. During the early years of computing, a terminal was called the ____. secondary c. dumb end terminal d. primary ANS: A 28. A primary that performs ____ polling polls only the first terminal, which then passes the poll to the second terminal, and each successive terminal passes the poll along. a. roll-call c. hub b. selection d. terminal ANS: C 29. line. a. b. With ____ connections, polling is not necessary because there is only one terminal per point-to-point multipoint c. d. terminal-to-point primary-to-point ANS: A 30. A ____ port is a connection in which eight data lines transmit an entire byte of data at one moment in time. a. serial c. DIN b. parallel d. USB ANS: B 31. The ______ protocol is a high-speed protocol commonly found on Apple laptops and incorporates two currently existing standards. a. USB c. SCSI b. async d. Thunderbolt ANS: D Chapter 5: Making Connections Efficient: Multiplexing and Compression MULTIPLE CHOICE 1. Presently, a medium can be divided in three basic ways: a division of ____, a division of time, and a division of transmission codes. a. frequencies c. wavelength b. amplitudes d. direction ANS: A 2. ____ is the assignment of nonoverlapping frequency ranges to each ÒuserÓ of a medium. a. Time division multiplexing (TDM) c. Amplitude division multiplexing (ADM) b. Transmission code multiplexing (TCM) d. Frequency division multiplexing (FDM) ANS: D 3. To allow multiple users to share a single medium, FDM assigns each user a separate ____. a. time slot c. channel b. transmission code d. amplitude ANS: C 4. First-generation cellular telephone systems allocated channels using frequency ranges within the 800 to ____ megahertz (MHz) spectrum. a. 830 c. 930 b. 900 d. 960 ANS: B 5. The device that is attached to the receiving end of the medium and splits off each signal to deliver it to the appropriate receiver is called the second multiplexor, or ____. a. multiplexor c. splitxor b. endplexor d. demultiplexor ANS: D 6. In FDM, ____ take up frequencies that might be used for other data channels, thus introducing a certain level of wastefulness. a. guard bands c. multiplexors b. channels d. demultiplexors ANS: A 7. Since time division multiplexing was introduced, it has split into two roughly parallel but separate technologies: synchronous time division multiplexing and ____ time division multiplexing. a. fixed c. inverse b. statistical d. empirical ANS: B 8. ____ gives each incoming source signal a turn to be transmitted, proceeding through the sources in round-robin fashion. a. Statistical time division multiplexing (Stat TDM) b. Empirical time division multiplexing (ETDM) c. Synchronous time division multiplexing (Sync TDM) d. Fixed time division multiplexing (FTDM) ANS: C 9. Under normal circumstances, the synchronous time division multiplexor maintains a simple ____ sampling order of the input devices. a. round-robin c. LIFO b. FIFO d. FILO ANS: A 10. Three types of synchronous time division multiplexing that are popular today are T-1 multiplexing, ____ multiplexing, and SDH. a. EIA-232F c. SONET b. IPS/SPX d. RS-232 ANS: C 11. In the 1960s, AT&T created a service known as ____, which multiplexed digital data and digitized voice onto a high-speed telephone line with a data rate of 1.544 megabits per second. a. ISDN c. SONET b. T-1 d. SDH ANS: B a. b. 12. ____ multiplexing is the multiplexing technique used to support SONET. FDM c. Frequency division ADM d. Synchronous time division ANS: D a. b. 13. A ____ multiplexes 24 input channels together onto one high-speed telephone line. T-1 system c. SDH system SONET system d. congruent system ANS: A a. b. 14. A T-1 system multiplexes _______ into each frame. a single ASCII character c. a single SYNC bit a single LENGTH byte d. a single SYNC byte ANS: C a. b. 15. SONET was developed in the United States by ____. ISO c. IEEE ANSI d. IETF ANS: B