Chapter 1



Chapter 8

Telecommunications, Networks, and Wireless Computing

True-False Questions

| |When selecting appropriate technologies for enterprise networking, Internet technology, XML, and Java allow for maximum |

| |connectivity and application integration. |

| | |

| |Answer: False Difficulty: Medium Reference: p. 266 |

| |The use of packet switching to increase telecommunications transmission efficiency is one of the three major developments |

| |that has shaped contemporary digital telecommunications systems. |

| | |

| |Answer: True Difficulty: Medium Reference: p. 267 |

| |Public networking is the linking of separate networks, each of which retains its own identity, into an interconnected |

| |network. |

| | |

| |Answer: False Difficulty: Medium Reference: p. 267 |

| |Message switching is a technology that breaks messages into small, fixed bundles of data and routes them in the most |

| |economical way through any available communications channel. |

| | |

| |Answer: False Difficulty: Medium Reference: p. 268 |

| |Peer-to-peer networking has become the predominant model for corporate computing. |

| | |

| |Answer: False Difficulty: Medium Reference: p. 268 |

| |The Internet is based on peer-to-peer networking. |

| | |

| |Answer: False Difficulty: Medium Reference: p. 268 |

| |A data server is a specialized communications processor that forwards data from one network to another network. |

| | |

| |Answer: False Difficulty: Medium Reference: p. 268 |

| |The X.25 packet switching standard uses packets of 128 bytes each. |

| | |

| |Answer: True Difficulty: Easy Reference: p. 268 |

| |The OSI model is the dominant model for achieving connectivity among different networks, providing an agreed-on method for |

| |breaking up digital messages into packets, routing them to the proper addresses, and then reassembling them into coherent |

| |messages. |

| | |

| |Answer: False Difficulty: Medium Reference: p. 269 |

| |The PDA connectivity model is the one used in the Internet. |

| | |

| |Answer: False Difficulty: Medium Reference: p. 269 |

| |If two computers are based on different hardware and software platforms, they will not be able to communicate via TCP/IP. |

| | |

| |Answer: False Difficulty: Medium Reference: p. 270 |

| |A digital signal is a continuous waveform. |

| | |

| |Answer: False Difficulty: Easy Reference: p. 270 |

| |Until recently, fiber-optic cable was the least expensive medium for telecommunications. |

| | |

| |Answer: False Difficulty: Easy Reference: p. 271 |

| |Optical networks can transmit voice, data, and video. |

| | |

| |Answer: True Difficulty: Easy Reference: p. 271 |

| |Presently, a problem with optical transmission is that it must convert data back and forth to electrical signals. |

| | |

| |Answer: True Difficulty: Medium Reference: p. 271 |

| |The electromagnetic spectrum is the wireless transmission medium. |

| | |

| |Answer: True Difficulty: Medium Reference: p. 272 |

| |Infrared transmissions fall in a higher frequency range than microwave transmissions. |

| | |

| |Answer: True Difficulty: Hard Reference: p. 272 |

| |Today paging devices can transmit short alphanumeric messages. |

| | |

| |Answer: True Difficulty: Easy Reference: p. 273 |

| |Personal communication services are entirely digital. |

| | |

| |Answer: True Difficulty: Hard Reference: p. 273 |

| |Mobile data networks are not explicitly designed for two-way transmissions of data files. |

| | |

| |Answer: False Difficulty: Medium Reference: p. 274 |

| |Security is a problem for wireless transmission because it is easily intercepted. |

| | |

| |Answer: True Difficulty: Easy Reference: p. 274 |

| |The bit rate is frequently smaller than the baud rate. |

| | |

| |Answer: False Difficulty: Hard Reference: p. 274 |

| |Bandwidth is the highest frequency that the channel can accommodate. |

| | |

| |Answer: False Difficulty: Medium Reference: p. 274 |

| |Ring and bus topologies are used in LANs. |

| | |

| |Answer: True Difficulty: Easy Reference: p. 276 |

| |Switched lines are continuously available for transmission because they have been changed from voice lines to data lines. |

| | |

| |Answer: False Difficulty: Hard Reference: p. 279 |

| |When using a value-added network, subscribers pay only for the amount of data they transmit plus a subscription fee. |

| | |

| |Answer: True Difficulty: Easy Reference: p. 279 |

| |ATM parcels information into 8-byte cells, allowing data to be transmitted between computers from different vendors at high |

| |speeds. |

| | |

| |Answer: True Difficulty: Medium Reference: p. 281 |

| |Basic rate ISDN can transmit data at a rate of 512 kilobits per second on an existing local telephone line. |

| | |

| |Answer: False Difficulty: Hard Reference: p. 281 |

| |A digital subscriber line can operate over existing copper telephone lines and has a higher transmission capacity than ISDN. |

| | |

| |Answer: True Difficulty: Easy Reference: p. 281 |

| |ADSL supports a transmission rate of 1.5 to 9 megabits per second when receiving data. |

| | |

| |Answer: True Difficulty: Easy Reference: p. 281 |

| |Presently, a cable modem has stronger capabilities for receiving data than for sending data. |

| | |

| |Answer: True Difficulty: Medium Reference: p. 281 |

| |A T1 line is a dedicated telephone connection of 24 channels. |

| | |

| |Answer: True Difficulty: Medium Reference: p. 281 |

| |A T1 channel can be configured to carry either voice or data traffic. |

| | |

| |Answer: True Difficulty: Easy Reference: p. 281 |

| |Cable modems provide high-speed transmission over cable TV lines and are shared by many users. |

| | |

| |Answer: True Difficulty: Easy Reference: p. 281 |

| |A broadband medium can transmit multiple channels of data simultaneously. |

| | |

| |Answer: True Difficulty: Medium Reference: p. 281 |

| |Communications companies and commercial on-line services offer electronic mail to their users. |

| | |

| |Answer: True Difficulty: Easy Reference: p. 282 |

| |The ability of two or more people at distant locations to edit and modify the same document simultaneously is called |

| |teleconferencing. |

| | |

| |Answer: False Difficulty: Easy Reference: p. 284 |

| |Digital learning refers to instruction delivered through purely digital technology, such as CD-ROMs, the Internet, or private|

| |networks. |

| | |

| |Answer: False Difficulty: Medium Reference: p. 285 |

| |EDI allows computer-to-computer exchange of standardized documents between two organizations and lowers transaction costs. |

| | |

| |Answer: True Difficulty: Easy Reference: p. 286 |

| |EDI differs from e-mail in that it transmits an actual structured transaction as opposed to an unstructured text message such|

| |as a letter. |

| | |

| |Answer: True Difficulty: Medium Reference: p. 286 |

Multiple- Choice Questions

| |A collection of compatible hardware and software arranged to communication information from one location to another best|

| |describes: |

| | |

| |a. telecommunication system. |

| |b. legacy system. |

| |c. corporate system. |

| |d. communication system. |

| |e. network operating system. |

| | |

| |Answer: a Difficulty: Medium Reference: p. 266 |

| |Various networks that are linked together to make information flow freely throughout different parts of the organization|

| |and between the organization and its external environment best describes: |

| | |

| |a. internetworking. |

| |b. enterprise networking. |

| |c. cooperative networking. |

| |d. extranet. |

| |e. virtual private networking. |

| | |

| |Answer: b Difficulty: Medium Reference: p. 267 |

| |Which of the following is a technology that breaks messages into small, fixed bundles of data and routes them in the |

| |most economical way through any available communications channel? |

| | |

| |a. ISDN |

| |b. Dense wavelength division multiplexing |

| |c. Packet switching |

| |d. Time division multiplexing |

| |e. TDMA |

| | |

| |Answer: c Difficulty: Medium Reference: p. 268 |

| |Which of the following is the connectivity model used in the Internet? |

| | |

| |a. ISDN |

| |b. DWDM |

| |c. GSM |

| |d. TCP/IP |

| |e. OSI |

| | |

| |Answer: d Difficulty: Medium Reference: p. 269 |

| |Which of the following is not one of the TCP/IP layers? |

| | |

| |a. Application layer |

| |b. Presentation layer |

| |c. Transportation layer |

| |d. Internet layer |

| |e. Network interface layer |

| | |

| |Answer: b Difficulty: Hard Reference: p. 269 |

| |“Crosstalk” is: |

| | |

| |a. two data communications on the same fiber-optic cable. |

| |b. two computers of different architecture talking to each other. |

| |c. interference with the signals on twisted wire media during high-speed transmission. |

| |d. set up by protocols. |

| |e. changing an analog signal to a digital one. |

| | |

| |Answer: c Difficulty: Medium Reference: p. 270 |

| |Optical networks transmit: |

| | |

| |a. voice. |

| |b. data |

| |c. video. |

| |d. using pulses of light. |

| |e. All of the above |

| | |

| |Answer: e Difficulty: Easy Reference: p. 271 |

| |Fiber-optic cable consists of: |

| | |

| |a. strands of clear glass fibers. |

| |b. glass fibers wound with copper wire. |

| |c. twisted pairs of glass fibers. |

| |d. dedicated 10-megabit lines. |

| |e. glass fibers transmitting an analog signal. |

| | |

| |Answer: a Difficulty: Easy Reference: p. 271 |

| |The part of a network that handles major traffic and provides the primary path for traffic flowing to or from other |

| |networks best describes: |

| | |

| |a. bus. |

| |b. switch. |

| |c. backbone. |

| |d. server. |

| |e. node. |

| | |

| |Answer: c Difficulty: Medium Reference: p. 271 |

| |The ability of a single communications channel to carry data transmissions from multiple sources simultaneously best |

| |defines: |

| | |

| |a. packet switching. |

| |b. circuit switching. |

| |c. parallel processing. |

| |d. multiplexing. |

| |e. baseband. |

| | |

| |Answer: d Difficulty: Medium Reference: p. 271 |

| |Technology for boosting transmission capacity of optical fiber by using many different wavelengths to carry separate |

| |streams of data over the same fiber strand at the same time best describes: |

| | |

| |a. optical division multiplexing. |

| |b. dense wavelength division multiplexing. |

| |c. digital streamlined multiplexing. |

| |d. broadband multiplexing. |

| |e. Wi-Fi. |

| | |

| |Answer: b Difficulty: Hard Reference: p. 271 |

| |DWDM uses: |

| | |

| |a. infrared data transmission. |

| |b. satellite transmissions. |

| |c. different colors of light to carry different messages over the same strand at the same time. |

| |d. differently-timed pulses of light to carry different messages over the same strand at the same time. |

| |e. a single wavelength per strand. |

| | |

| |Answer: c Difficulty: Hard Reference: p. 271 |

| |Common technologies for wireless data transmission include: |

| | |

| |a. microwave transmission. |

| |b. communication satellites. |

| |c. pagers. |

| |d. personal communication services. |

| |e. All of the above |

| | |

| |Answer: e Difficulty: Easy Reference: p. 272 |

| |Microwave signals: |

| | |

| |a. follow a straight line. |

| |b. require the transmission stations be positioned 37 miles apart. |

| |c. do not bend with the curvature of the earth. |

| |d. are widely used for high-volume, long-distance, point-to-point communication. |

| |e. All of the above |

| | |

| |Answer: d Difficulty: Easy Reference: p. 272 |

| |Communications satellites are: |

| | |

| |a. relay stations for fiber-optic transmissions. |

| |b. outside the electromagnetic spectrum. |

| |c. used mainly by cell phones. |

| |d. usually in very high orbits so they will not interfere with space stations. |

| |e. cost effective for transmitting large quantities of data over very long distances. |

| | |

| |Answer: e Difficulty: Medium Reference: p. 272 |

| |In ascending order, the frequency ranges for communications media are: |

| | |

| |a. radio, infrared, ultraviolet, visible light, X-ray, and gamma/cosmic. |

| |b. X-ray, infrared, ultraviolet, microwave, visible light, and gamma/cosmic. |

| |c. radio, microwave, infrared, visible light, ultraviolet light, X-ray, and gamma/cosmic. |

| |d. gamma/cosmic, X-ray, visible light, ultraviolet, microwave, infrared, and radio. |

| |e. radio, microwave, infrared, ultraviolet, visible light, X-ray, and gamma/cosmic. |

| | |

| |Answer: c Difficulty: Hard Reference: p. 272 |

| |A wireless cellular technology that uses lower-power, higher-frequency radio waves than does cellular technology best |

| |defines: |

| | |

| |a. personal digital assistants. |

| |b. packet distribution networks. |

| |c. paging system. |

| |d. personal communications services. |

| |e. mobile data networks. |

| | |

| |Answer: d Difficulty: Medium Reference: p. 273 |

| |Paging devices today can: |

| | |

| |a. send and receive short alphanumeric messages. |

| |b. send only analog signals. |

| |c. send only digital signals. |

| |d. be used over long distances with special microwave transmitters. |

| |e. support groupware applications. |

| | |

| |Answer: a Difficulty: Easy Reference: p. 273 |

| |In a cell-phone network, each radio antenna cell normally covers: |

| | |

| |a. a 30-mile area, overlapping with adjacent cells by about 5 miles. |

| |b. radio and microwave transmissions, but not digital transmission. |

| |c. only phones of the particular cell-phone service being used. |

| |d. an eight-mile hexagonal cell. |

| |e. line-of-sight to any other antenna. |

| | |

| |Answer: d Difficulty: Medium Reference: p. 273 |

| |PDAs: |

| | |

| |a. have built-in wireless telecommunications capabilities. |

| |b. are small, pen-based, handheld computers. |

| |c. are capable of entirely digital transmission. |

| |d. have work-organization software. |

| |e. All of the above |

| | |

| |Answer: e Difficulty: Easy Reference: p. 273 |

| |Because wireless transmission can be easily intercepted: |

| | |

| |a. it is not useful in digital environments. |

| |b. security and privacy are more difficult. |

| |c. it is best used for cable television. |

| |d. even a radio can pick up the digital signal. |

| |e. Both a and c |

| | |

| |Answer: b Difficulty: Easy Reference: p. 274 |

| |Data can be transmitted seamlessly between different wireless networks: |

| | |

| |a. only over short distances. |

| |b. only if they use compatible standards. |

| |c. only over the Internet. |

| |d. only with government permission. |

| |e. only when cellular phones are used. |

| | |

| |Answer: b Difficulty: Hard Reference: p. 274 |

| |At higher speeds, a single signal change: |

| | |

| |a. can transmit several messages at once. |

| |b. can transmit microwave frequencies. |

| |c. can be measured only in hertz. |

| |d. can transmit more than one bit at a time. |

| |e. can decrease the baud rate. |

| | |

| |Answer: d Difficulty: Medium Reference: p. 274 |

| |A change in signal from positive to negative or vice versa that is used as a measure of transmission speed best defines:|

| | |

| |a. baud. |

| |b. bits per second. |

| |c. multiplex. |

| |d. digital differential. |

| |e. transmission rate. |

| | |

| |Answer: a Difficulty: Medium Reference: p. 274 |

| |At its fastest, fiber-optic cable can transmit data at speeds of: |

| | |

| |a. 1.544 megabits per second. |

| |b. 1024 bits per second. |

| |c. up to 2.56 megabits per second. |

| |d. up to 6 terabits per second. |

| |e. 1 terabit per second. |

| | |

| |Answer: d Difficulty: Medium Reference: p. 275 |

| |A star network is a: |

| | |

| |a. network topology in which all computers and other devices are connected to a central hub. |

| |b. network topology in which all computers are linked by a closed loop in a manner that passes data in one direction |

| |from one computer to another. |

| |c. network topology linking a number of computers by a single circuit with all messages broadcast to the entire network.|

| |d. network architecture that gives equal power to all computers on the network. |

| |e. telecommunications network that spans a large geographical distance. |

| | |

| |Answer: a Difficulty: Medium Reference: p. 276 |

| |A ring network is a: |

| | |

| |a. network topology in which all computers and other devices are connected to a central hub. |

| |b. network topology in which all computers are linked by a closed loop in a manner that passes data in one direction |

| |from one computer to another. |

| |c. network topology linking a number of computers by a single circuit with all messages broadcast to the entire network.|

| |d. network architecture that gives equal power to all computers on the network. |

| |e. telecommunications network that spans a large geographical distance. |

| | |

| |Answer: b Difficulty: Medium Reference: p. 276 |

| |Peer-to-peer is a: |

| | |

| |a. network topology in which all computers and other devices are connected to a central hub. |

| |b. network topology in which all computers are linked by a closed loop in a manner that passes data in one direction |

| |from one computer to another. |

| |c. network topology linking a number of computers by a single circuit with all messages broadcast to the entire network.|

| |d. network architecture that gives equal power to all computers on the network. |

| |e. telecommunications network that spans a large geographical distance. |

| | |

| |Answer: d Difficulty: Medium Reference: p. 276 |

| |A bus network is a: |

| | |

| |a. network topology in which all computers and other devices are connected to a central hub. |

| |b. network topology in which all computers are linked by a closed loop in a manner that passes data in one direction |

| |from one computer to another. |

| |c. network topology linking a number of computers by a single circuit with all messages broadcast to the entire network.|

| |d. network architecture that gives equal power to all computers on the network. |

| |e. telecommunications network that spans a large geographical distance. |

| | |

| |Answer: c Difficulty: Medium Reference: p. 276 |

| |The LAN network interface card: |

| | |

| |a. specifies the data transmission rate. |

| |b. specifies the size of the message units. |

| |c. specifies the addressing information attached to each message. |

| |d. specifies the network topology. |

| |e. All of the above |

| | |

| |Answer: e Difficulty: Easy Reference: p. 276 |

| |Which of the following is the Wi-Fi mode where wireless devices communicate with a wired LAN via access points? |

| | |

| |a. Peer mode |

| |b. Ad-hoc mode |

| |c. Star mode |

| |d. Infrastructure mode |

| |e. Multiplexed mode |

| | |

| |Answer: d Difficulty: Hard Reference: p. 277 |

| |Which of the following is the Wi-Fi mode where wireless devices communicate with each other directly and do not use an |

| |access point? |

| | |

| |a. Peer mode |

| |b. Ad-hoc mode |

| |c. Star mode |

| |d. Infrastructure mode |

| |e. Multiplexed mode |

| | |

| |Answer: b Difficulty: Hard Reference: p. 277 |

| |Which of the following is a specific geographic location in which an access point provides public Wi-Fi network service?|

| | |

| |a. Connect point |

| |b. Peer point |

| |c. Hot spot |

| |d. Node location |

| |e. Wi-Fi channel |

| | |

| |Answer: c Difficulty: Medium Reference: p. 278 |

| |A private, multipath, data-only, third-party-managed network that multiple organizations use on a subscription basis |

| |best describes: |

| | |

| |a. local area network. |

| |b. peer-to-peer network. |

| |c. Wi-Fi network. |

| |d. wide area network. |

| |e. value-added network. |

| | |

| |Answer: e Difficulty: Medium Reference: p. 279 |

| |A networking technology that parcels information into 8-byte cells, allowing data to be transmitted between computers |

| |from different vendors at high speeds best describes: |

| | |

| |a. broadband. |

| |b. asynchronous transfer mode. |

| |c. integrated services digital network. |

| |d. converged network. |

| |e. star network. |

| | |

| |Answer: b Difficulty: Medium Reference: p. 281 |

| |Primary Rate ISDN: |

| | |

| |a. parcels information into 8-byte cells. |

| |b. requires a fiber-optic line. |

| |c. operates over cable TV lines as well as telephone lines. |

| |d. is used for high-capacity Internet connections. |

| |e. offers transmission capacities in the megabit range. |

| | |

| |Answer: e Difficulty: Hard Reference: p. 281 |

| |Broadband: |

| | |

| |a. works only for cable TV connections. |

| |b. designates a communications medium that can transmit multiple channels of data simultaneously. |

| |c. enables voice and data to run on a single network. |

| |d. is for high-frequency transmissions. |

| |e. does not maintain separate networks for voice and data. |

| | |

| |Answer: b Difficulty: Easy Reference: p. 281 |

| |A voice mail system: |

| | |

| |a. is necessary for groupware to work efficiently. |

| |b. allows data conferencing. |

| |c. digitizes the sender’s spoken message, transmits it over a network, and stores it for later retrieval. |

| |d. allows simultaneous conference via telephone. |

| |e. All of the above. |

| | |

| |Answer: c Difficulty: Easy Reference: p. 283 |

| |Electronic conferencing is growing in popularity because: |

| | |

| |a. travel time and costs are saved. |

| |b. special software is not required. |

| |c. any T1 line can use it. |

| |d. employees can be monitored more closely. |

| |e. of all of the above. |

| | |

| |Answer: a Difficulty: Easy Reference: p. 284 |

| |“E-learning” is the term used to describe: |

| | |

| |a. training in network technologies. |

| |b. surfing the Internet. |

| |c. training delivered over a distance. |

| |d. on-line instruction delivered over the Internet or private networks. |

| |e. what companies are finding out about new technologies. |

| | |

| |Answer: d Difficulty: Medium Reference: p. 285 |

Fill In the Blanks

| |A(n) telecommunications system is a collection of compatible hardware and software arranged to communicate information from |

| |one location to another. |

| | |

| |Difficulty: Easy Reference: p. 266 |

| |A(n) router is a specialized communications processor that forwards data packets from one network to another network. |

| | |

| |Difficulty: Medium Reference: p. 268 |

| |Packet switching is technology that breaks messages into small, fixed bundles of data and routes them in the most economical |

| |way through any available communications channel. |

| | |

| |Difficulty: Easy Reference: p. 268 |

| |A(n) protocol is a set of rules and procedures that govern transmission between the components in a network. |

| | |

| |Difficulty: Medium Reference: p. 269 |

| |A(n) analog signal is a continuous waveform that passes through a communications medium. |

| | |

| |Difficulty: Medium Reference: p. 270 |

| |A(n) digital signal is a discrete waveform that transmits data coded into two discrete states as 1-bits and 0-bits, which are|

| |represented as on-off electrical pulses. |

| | |

| |Difficulty: Easy Reference: p. 270 |

| |A(n) modem is a device for translating a computer’s digital signals into analog form for transmission over ordinary telephone|

| |lines, or for translating analog signals back into digital form for reception by a computer. |

| | |

| |Difficulty: Easy Reference: p. 270 |

| |A(n) channel is the link by which data or voice is transmitted between sending and receiving devices in a network. |

| | |

| |Difficulty: Medium Reference: p. 270 |

| |A(n) twisted wire is a transmission medium consisting of pairs of copper wires. |

| | |

| |Difficulty: Easy Reference: p. 270 |

| |A(n) coaxial cable is a transmission medium consisting of thickly insulated copper wire that can transmit large volumes of |

| |data quickly. |

| | |

| |Difficulty: Easy Reference: p. 271 |

| |A(n) fiber-optic cable is a fast, light, and durable transmission medium consisting of thin strands of clear glass fiber |

| |bound into cables. |

| | |

| |Difficulty: Easy Reference: p. 271 |

| |A(n) backbone is the part of a network that handles the major traffic and provides the primary path for traffic flowing to or|

| |from other networks. |

| | |

| |Difficulty: Medium Reference: p. 271 |

| |A(n) optical network is high-speed networking technology for transmitting data in the form of light pulses. |

| | |

| |Difficulty: Medium Reference: p. 271 |

| |Dense wave division multiplexing is a technology for boosting transmission capacity of optical fiber by using many different |

| |wavelengths to carry separate streams of data over the same fiber strand at the same time. |

| | |

| |Difficulty: Hard Reference: p. 271 |

| |Microwave is a high-volume, long-distance point-to-point transmission in which high-frequency radio signals are transmitted |

| |through the atmosphere from one terrestrial transmission station to another. |

| | |

| |Difficulty: Medium Reference: p. 272 |

| |Satellite transmission of data uses orbiting satellites that serve as relay stations for transmitting microwave signals over |

| |very long distances. |

| | |

| |Difficulty: Easy Reference: p. 272 |

| |A(n) paging system is a wireless transmission technology in which the receiver beeps when the user receives a message; it is |

| |used to transmit short alphanumeric messages. |

| | |

| |Difficulty: Easy Reference: p. 273 |

| |A(n) cellular telephone is a device that transmits voice or data using radio waves to communicate with radio antennas placed |

| |within adjacent geographic areas. |

| | |

| |Difficulty: Easy Reference: p. 273 |

| |Personal communication services use a wireless cellular technology that uses lower power, higher-frequency radio waves than |

| |does cellular technology. |

| | |

| |Difficulty: Medium Reference: p. 273 |

| |A(n) personal digital assistant is a small, pen-based, hand-held computer with built-in wireless telecommunications capable |

| |of entirely digital communications transmission. |

| | |

| |Difficulty: Medium Reference: p. 273 |

| |A(n) smart phone is a wireless phone with voice, text, and Internet capabilities. |

| | |

| |Difficulty: Easy Reference: p. 274 |

| |A(n) mobile data network is a wireless network that enables two-way transmission of data files cheaply and efficiently. |

| | |

| |Difficulty: Medium Reference: p. 274 |

| |Baud is a change in signal from positive to negative or vice versa that is used as a measure of transmission speed. |

| | |

| |Difficulty: Medium Reference: p. 274 |

| |Bandwidth is the capacity of a communications channel as measured by the difference between the highest and lowest |

| |frequencies that can be transmitted by that channel. |

| | |

| |Difficulty: Medium Reference: p. 274 |

| |A(n) local area network requires its own dedicated channels and encompasses a limited distance, usually one building or |

| |several buildings in proximity. |

| | |

| |Difficulty: Medium Reference: p. 275 |

| |Topology is the way in which the components of a network are connected. |

| | |

| |Difficulty: Easy Reference: p. 276 |

| |A(n) bus network has a number of computers linked by a single circuit with all messages broadcast to the entire network. |

| | |

| |Difficulty: Medium Reference: p. 276 |

| |A(n) ring network has a number of computers linked by a closed loop in a manner that passes data in one direction from one |

| |computer to another. |

| | |

| |Difficulty: Medium Reference: p. 276 |

| |A(n) network operating system is special software that routes and manages communications on the network and coordinates |

| |network resources. |

| | |

| |Difficulty: Easy Reference: p. 276 |

| |A(n) peer-to-peer network architecture gives equal power to all computers on the network. |

| | |

| |Difficulty: Easy Reference: p. 276 |

| |A(n) wide area network is a network that spans a large geographical distance. |

| | |

| |Difficulty: Easy Reference: p. 279 |

| |A(n) dedicated line is a phone line that is continuously available for transmission by a lessee. |

| | |

| |Difficulty: Easy Reference: p. 279 |

| |A(n) value-added network is a private, multipath, data-only, third-party-managed network that multiple organizations use on a|

| |subscription basis. |

| | |

| |Difficulty: Medium Reference: p. 279 |

| |A(n) frame relay is a shared network service technology that packages data into bundles for transmission but does not use |

| |extensive error-correction routines. |

| | |

| |Difficulty: Medium Reference: p. 281 |

| |Asynchronous transfer mode is a networking technology that parcels information into 8-byte cells, allowing data to be |

| |transmitted between computers from different vendors at high speeds. |

| | |

| |Difficulty: Medium Reference: p. 281 |

| |Integrated Services Digital Network is an international standard for transmitting voice, video, image, and data to support a |

| |wide range of service over the public telephone lines. |

| | |

| |Difficulty: Hard Reference: p. 281 |

| |Digital subscriber line refers to a group of technologies providing high-capacity transmission over existing copper telephone|

| |lines. |

| | |

| |Difficulty: Medium Reference: p. 281 |

| |A(n) T1 line is a dedicated telephone connection comprising 24 channels that can support a data transmission rate of 1.544 |

| |megabits per second. |

| | |

| |Difficulty: Easy Reference: p. 281 |

| |Broadband is a high-speed transmission technology; it also designates a single communications medium that can transmit |

| |multiple channels of data simultaneously. |

| | |

| |Difficulty: Medium Reference: p. 281 |

| |A(n) converged network is a network with technology to enable voice, video, and data to run over a single network. |

| | |

| |Difficulty: Medium Reference: p. 281 |

Essay Questions

| |Briefly describe the three major developments that have shaped contemporary digital telecommunications systems. |

| | |

| |The textbook mentions client/server computing, packet switching, and TCP/IP as the three major developments. Client/server |

| |computing is a model of computing that divides the processing between client computers and servers on a network. The tasks |

| |are assigned to the machine most able to perform the tasks. Packet switching breaks messages into small, fixed bundles of |

| |data and routes them in the most economical way through any available communications channel. Packet switching enables |

| |packets to be transmitted independently through various communications channels. TCP/IP is the connectivity model of the |

| |Internet, providing a universally agreed-on method for breaking up digital messages into packets, routing them to the proper |

| |addresses, and then reassembling them into coherent messages. |

| |List and describe the three major LAN topologies. What are the advantages and disadvantages of each? |

| | |

| |Star, bus, and ring are the three major LAN topologies. The star topology consists of a central host computer connected to a|

| |number of smaller computers or terminals. It is useful for applications where some processing must be centralized and some |

| |can be performed locally. All communications between points in the network must pass through the central computer. One |

| |problem with this topology is that everyone in the network goes down if the central computer fails for any reason. The bus |

| |topology links a number of computers by a single circuit made of twisted wire, coaxial cable, or fiber-optic cable. All |

| |signals are broadcast in both directions to the entire network, with special software to identify which components receive |

| |each message. There is no central computer controlling the network. If one of the computers fails, none of the others are |

| |affected, and work can continue. However, since the channel can handle only one message at a time, performance can degrade |

| |if there is a high volume of network traffic. The ring topology like the bus network does not rely on a central host and |

| |will not necessarily break down if one of the component computers malfunctions. Each computer in the network can communicate|

| |directly with any other computer, and each processes its own applications independently. However, in a ring topology, the |

| |connecting wire forms a closed loop, and all data flows in one direction around the loop. |

| |What is TCP/IP? Identify its layers. |

| | |

| |TCP/IP is the connectivity model used by the Internet; it provides a universally agreed-on method for breaking up digital |

| |messages into packets, routing them to the proper addresses, and then reassembling them into coherent messages. The TCP/IP |

| |layers are application, transport, internet, and network interface. |

| |Distinguish between an analog signal and a digital signal. |

| | |

| |An analog signal is a continuous waveform passing through a communications medium. Analog signals handle voice |

| |communications and reflect variations in pitch. A digital signal is a discrete, rather than a continuous waveform, using |

| |only two states, 1-bits and 0-bits representing either/or conditions or on-off electrical pulses. |

| | |

| |Standard telephone lines speak analog; computers speak digital. To communicate, the digital signal either 1) must be changed|

| |to an analog signal as it travels the medium, then changed back to a digital signal for the computer at the other end, or 2) |

| |sent in digital pulses over a medium that is also digital. |

| |List and describe the three forms of wired transmission used in the telecommunications industry, and give one advantage and |

| |one disadvantage for each. |

| | |

| |Twisted wire refers to strands of copper wire twisted in pairs. Most standard telephone lines are twisted pairs and have |

| |been for many years. Twisted pairs can be used for digital transmission as well as analog. Its main advantages are low cost|

| |and it is already in place. Disadvantages include relatively slow for transmitting data, and the problem of “crosstalk” in |

| |which the signal “bleeds” from one wire to another during high-speed transmission. Coaxial cable is thickly insulated copper|

| |wire, which can transmit a larger volume of data than twisted wire. Advantages include its speed and having less |

| |interference. Disadvantages include the cable is thick and heavy, and it is hard to install in many buildings. Also, it |

| |cannot support analog phone conversations. Fiber-optic cable consists of thousands of very thin strands of clear glass |

| |fiber, bound into a cable. Data are transmitted over each strand by pulses of light, which are sent by laser at very high |

| |speed. Fiber optic advantages include faster, lighter, more durable, and the ability to transfer large volumes of data |

| |quickly. Its disadvantages are that it is difficult to work with, expensive, and harder to install. |

| |Define “wireless transmission” and list at least two advantages and two disadvantages to its use. |

| | |

| |Wireless transmission sends signals (using the electromagnetic spectrum) through air or space without any physical tether. |

| |Common technologies for wireless transmission include microwave transmission, communication satellites, pagers, cell phones, |

| |personal communication services, smart phones, personal digital assistants, and mobile data networks. Advantages include no |

| |limitation on where communications may take place, since the signal can be bounced off satellites to line-of-sight towers and|

| |no limitation of the movement of the persons communicating, because no wires are involved. Disadvantages include being more |

| |expensive, slower, and more error prone than wired networks. Security and privacy are difficult because wireless |

| |transmissions are easily intercepted. Different wireless networks cannot transmit data seamlessly if they use incompatible |

| |standards or different frequencies. |

| |Briefly discuss Wi-Fi. |

| | |

| |Wi-Fi is the emerging standard for wireless LANs. The 802.a standard transmits up to 54 Mbps in the unlicensed 5-Ghz |

| |frequency range and has an effective distance up to 30 meters. The 802.11b standard transmits up to 11 Mbps in the |

| |unlicensed 2.4 GHz band and has an effective distance up to 50 meters. The 802.11g standard transmits up to 54 Mbps in the |

| |2.4 GHz range. Wi-Fi systems can operate either in infrastructure or ad-hoc mode. When operating in infrastructure mode, |

| |wireless devices communicate with a LAN through access points. In ad-hoc mode, wireless devices communicate directly and do |

| |not use access points. |

| |What are at least five considerations management must examine to establish the telecommunications needs of a company? |

| | |

| |Management should consider the following: |

| | |

| |1. Distance—are the needs of the company local or long-distance? |

| |2. Services—what range of services will be needed (e-mail, EDI, voice mail, videoconferencing, graphics transmission)? Do |

| |they need to be integrated? |

| |3. Points of access—how many different locations and users in the organization require access to the communications |

| |services and capabilities? |

| |4. Utilization—what frequency and volume of communications does your firm anticipate? |

| |5. Cost—how much can you spend and on what? |

| |6. Security—what level of security and reliability must be maintained? |

| |7. Connectivity—how much time, money, and effort will be required to make sure all the components of the network or |

| |multiple networks can communicate with each other? |

| |Distinguish between EDI and ATM. |

| | |

| |ATM is “asynchronous transfer mode” and is capable of seamlessly switching voice, data, images, and video between users using|

| |computers from different vendors. EDI is the computer-to-computer exchange between two organizations of standard transaction|

| |documents such as invoices, bills of lading, and purchase orders. |

| |Distinguish between the two types of ISDN services and the two types of DSL services. |

| | |

| |ISDN—stands for Integrated Services Digital Network, and is an international standard for dial-up network access that |

| |integrates voice, data, image, and video services in a single link. Basic rate ISDN can transmit data at a rate of 128 |

| |kilobits per second on an existing local telephone line. Primary rate ISDN offers transmission capacities in the megabit |

| |range and is designed for large users of telecommunications services. |

| | |

| |DSL—stands for Digital Subscriber Line, and also carry e-mail, data, image, and video services in a single link over regular |

| |copper phone lines, but they have higher transmission capacities than ISDN. ADSL (asymmetric digital subscriber line) |

| |supports 1.5 to 9 megabits per second when receiving data and up to 640 kilobits per second when sending data. SDSL |

| |(symmetric digital subscriber line) supports the same transmission rate and can receive data at up to 3 megabits per second. |

| | |

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