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# Data Communications and Computer Networks A Business User’s Approach 8th Edition Curt White- Test Bank

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Data Communications and Computer Networks A Business User’s Approach 8th Edition Curt White- Test Bank

Sample Questions

Chapter 2: Fundamentals of Data and Signals

TRUE/FALSE

1. The terms “data” and “signal” mean the same thing.

ANS:  F                    PTS:   1                    REF:   28

1. By convention, the minimum and maximum values of analog data and signals are presented as voltages.

ANS:  T                    PTS:   1                    REF:   30

1. One of the primary shortcomings of analog data and analog signals is how difficult it is to separate noise from the original waveform.

ANS:  T                    PTS:   1                    REF:   30

1. The ability to separate noise from a digital waveform is one of the great strengths of digital systems.

ANS:  T                    PTS:   1                    REF:   30

1. A sine wave is common example used to demonstrate an analog signal.

ANS:  T                    PTS:   1                    REF:   30

1. The period of a signal can be calculated by taking the reciprocal of the frequency (1/frequency).

ANS:  T                    PTS:   1                    REF:   33

1. The telephone system transmits signals in the range of 150 Hz to 1500 Hz.

ANS:  F                    PTS:   1                    REF:   34

1. Attenuation in a medium such as copper wire is a logarithmic loss and is a function of distance and the resistance within the wire.

ANS:  T                    PTS:   1                    REF:   34

1. Like signals, data can be analog or digital.

ANS:  T                    PTS:   1                    REF:   31

1. Telephones, AM radio, FM radio, broadcast television, and cable television are the most common examples of analog data-to-digital signal conversion.

ANS:  F                    PTS:   1                    REF:   38

1. The NRZ-L encoding scheme is simple to generate and inexpensive to implement in hardware.

ANS:  T                    PTS:   1                    REF:   39

1. With NRZI, the receiver has to check the voltage level for each bit to determine whether the bit is a 0 or a 1.

ANS:  F                    PTS:   1                    REF:   39

1. With NRZ-L, the receiver has to check whether there is a change at the beginning of the bit to determine if it is a 0 or a 1.

ANS:  F                    PTS:   1                    REF:   40

1. An inherent problem with the NRZ-L and NRZI digital encoding schemes is that long sequences of 0s in the data produce a signal that never changes.

ANS:  T                    PTS:   1                    REF:   40

1. The big disadvantage of the Manchester schemes is that roughly half the time there will be two transitions during each bit.

ANS:  T                    PTS:   1                    REF:   40

1. Under some circumstances, the baud rate may equal the bps, such as in the Manchester encoding schemes.

ANS:  F                    PTS:   1                    REF:   41

1. Amplitude shift keying is restricted to only two possible amplitude levels: low and high.

ANS:  F                    PTS:   1                    REF:   43

1. Amplitude shift keying is susceptible to sudden noise impulses such as the static charges created by a lightning storm.

ANS:  T                    PTS:   1                    REF:   44

1. Frequency shift keying is susceptible to sudden noise spikes that can cause loss of data.

ANS:  F                    PTS:   1                    REF:   44

1. Phase changes are not affected by amplitude changes, nor are they affected by intermodulation distortions.

ANS:  T                    PTS:   1                    REF:   45

1. The bps of the data transmitted using quadrature amplitude modulation is four times the baud rate.

ANS:  F                    PTS:   1                    REF:   45

1. According to a famous communications theorem created by Nyquist, the sampling rate using pulse code modulation must be at least three times the highest frequency of the original analog waveform.

ANS:  F                    PTS:   1                    REF:   50

1. One of the most common forms of data transmitted between a transmitter and a receiver is textual data.

ANS:  T                    PTS:   1                    REF:   49

1. Certain control characters provide data transfer control between a computer source and computer destination.

ANS:  T                    PTS:   1                    REF:   51

1. IBM mainframe computers are major users of the EBCDIC character set.

ANS:  T                    PTS:   1                    REF:   51

1. ASCII is a data code rarely used in the world.

ANS:  F                    PTS:   1                    REF:   52

1. A byte consists of 8 bits.

ANS:  T                    PTS:   1                    REF:   52

1. One of the major problems with Unicode is that it cannot represent symbols other than those found in the English language.

ANS:  F                    PTS:   1                    REF:   53

1. ASCII is one of the supported code charts in Unicode.

ANS:  T                    PTS:   1                    REF:   53

1. In Unicode, the letter “r” is represented by the binary value of 0000 0000 0101 0100 0010.

ANS:  F                    PTS:   1                    REF:   53

MULTIPLE CHOICE

1. ____ are entities that convey meaning within a computer or computer system.
 a. Signals c. Impulse b. Data d. EMI

ANS:  B                    PTS:   1                    REF:   30

1. If you want to transfer data from one point to another, either via a physical wire or through radio waves, the data has to be converted into a(n) ____.
 a. hertz c. signal b. Unicode d. byte

ANS:  C                    PTS:   1                    REF:   30

1. ____ are represented as continuous waveforms that can be at an infinite number of points between some given minimum and maximum.
 a. Analog signals c. Digital data b. Digital signals d. Digital pulses

ANS:  A                    PTS:   1                    REF:   30

1. The most common example of ____ data is the human voice.
 a. sampling c. digital b. baud d. analog

ANS:  D                    PTS:   1                    REF:   30

1. Unfortunately, noise itself occurs as a(n) ____ waveform, and this makes it challenging, if not extremely difficult, to separate noise from an analog waveform that represents data.
 a. analog c. hertz b. digital d. byte

ANS:  A                    PTS:   1                    REF:   31

1. ____ are discrete waveforms, rather than continuous waveforms.
 a. Analog signals c. Digital signals b. Analog bauds d. Analog data

ANS:  C                    PTS:   1                    REF:   32

1. The three basic components of analog and digital signals are: amplitude, frequency, and ____.
 a. cycles c. hertz b. baud d. phase

ANS:  D                    PTS:   1                    REF:   33

1. The amplitude of a signal can be expressed as volts, ____, or watts.
 a. hertz c. bits b. amps d. bytes

ANS:  B                    PTS:   1                    REF:   33

1. The ____ of a signal is the number of times a signal makes a complete cycle within a given time frame.
 a. phase c. period b. amplitude d. frequency

ANS:  D                    PTS:   1                    REF:   33

1. Cycles per second, or frequency, is represented by ____.
 a. bytes c. bits b. hertz d. watts

ANS:  B                    PTS:   1                    REF:   33

1. The frequency range of the average human voice usually goes no lower than 300 Hz and no higher than approximately ____ Hz.
 a. 2200 c. 3400 b. 2400 d. 5300

ANS:  C                    PTS:   1                    REF:   34

1. The lowest note possible on the piano is ____ Hz, and the highest note possible is 4200 Hz.
 a. 30 c. 300 b. 80 d. 450

ANS:  A                    PTS:   1                    REF:   34

1. The bandwidth of a telephone system that transmits a single voice in the range of 300 Hz to 3400 Hz is ____ Hz.
 a. 10 c. 3100 b. 100 d. 3700

ANS:  C                    PTS:   1                    REF:   34

1. When traveling through any type of medium, a signal always experiences some loss of its power due to friction. This loss of power, or loss of signal strength, is called ____.
 a. amplification c. decibel b. friction d. attenuation

ANS:  D                    PTS:   1                    REF:   35

1. When a signal is amplified by an amplifier, the signal gains in ____.
 a. decibels c. bytes b. hertz d. watts

ANS:  A                    PTS:   1                    REF:   35

1. ____ is the process of sending data over a signal by varying either its amplitude, frequency, or phase.
 a. Amplification c. Attenuation b. Modulation d. Digital encoding

ANS:  B                    PTS:   1                    REF:   38

1. The ____ encoding scheme has a voltage change at the beginning of a 1 and no voltage change at the beginning of a 0.

ANS:  A                    PTS:   1                    REF:   39

1. The ____ digital encoding scheme is similar to the Manchester scheme in that there is always a transition in the middle of the interval.
 a. NRZ-L c. differential Manchester b. Bipolar-AMI d. NRZI

ANS:  C                    PTS:   1                    REF:   40

1. The Manchester encoding schemes are called ____, because the occurrence of a regular transition is similar to seconds ticking on a clock.
 a. continuous-clocking c. discrete-clocking b. analog-clocking d. self-clocking

ANS:  D                    PTS:   1                    REF:   40

1. The number of times a signal changes value per second is called the ____ rate.
 a. hertz c. watts b. baud d. volts

ANS:  B                    PTS:   1                    REF:   41

1. The data rate is measured in ____.
 a. bits per second (bps) c. bauds per second (bps) b. bytes per second (Bps) d. hertz per second (hps)

ANS:  A                    PTS:   1                    REF:   41

1. Using ____, when a device transmits a binary 0, a zero voltage is transmitted. When the device transmits a binary 1, either a positive voltage or a negative voltage is transmitted.
 a. Manchester c. differential Manchester b. bipolar-AMI d. NRZ-L

ANS:  B                    PTS:   1                    REF:   41

1. The primary advantage of a bipolar scheme is that when all the voltages are added together after a long transmission, there should be a total voltage of ____.
 a. -2 c. 0 b. -1 d. 1

ANS:  C                    PTS:   1                    REF:   41

1. The Manchester encoding schemes solve the synchronization problem but are relatively inefficient because they have a baud rate that is ____ the bps.
 a. equal to c. three times b. twice d. four times

ANS:  B                    PTS:   1                    REF:   42

1. A device that modulates digital data onto an analog signal and then demodulates the analog signal back to digital data is a ____.
 a. repeater c. hub b. switch d. modem

ANS:  D                    PTS:   1                    REF:   43

1. Three currently popular modulation techniques for encoding digital data and transmitting it over analog signals are amplitude shift keying, frequency shift keying, and ____ shift keying.
 a. noise c. strength b. baud d. phase

ANS:  D                    PTS:   1                    REF:   43

1. The simplest modulation technique is ____ shift keying.
 a. amplitude c. frequency b. phase d. noise

ANS:  A                    PTS:   1                    REF:   43

1. Frequency shift keying is subject to ____.
 a. baud noise c. intermodulation distortion b. bps distortion d. noise spikes

ANS:  C                    PTS:   1                    REF:   44

1. ____ shift keying represents 0s and 1s by different changes in the phase of a waveform.
 a. Amplitude c. Frequency b. Phase d. Noise

ANS:  B                    PTS:   1                    REF:   44

1. ____ shift keying incorporates four different phase angles, each of which represents 2 bits.

ANS:  D                    PTS:   1                    REF:   45

1. ____ modulation, which is commonly employed in contemporary modems, uses each signal change to represent 4 bits.

ANS:  A                    PTS:   1                    REF:   45

1. One encoding technique that converts analog data to a digital signal is ____.
 a. NRZ-L c. pulse code modulation (PCM) b. Manchester d. NRZ-I

ANS:  C                    PTS:   1                    REF:   46

1. Tracking an analog waveform and converting it to pulses that represent the wave’s height above (or below) a threshold is termed ____.
 a. pulse amplitude modulation (PAM) c. quantization b. codec d. quantization levels

ANS:  A                    PTS:   1                    REF:   46

1. When converting analog data to digital signals, the frequency at which the snapshots are taken is called the ____ rate.
 a. baud c. bps b. sampling d. byte

ANS:  B                    PTS:   1                    REF:   48

1. With ____, a codec tracks the incoming analog data by assessing up or down “steps.”
 a. differential Manchester c. NRZI b. Bipolar-AMI d. delta modulation

ANS:  D                    PTS:   1                    REF:   49

1. Three important data codes are EBCDIC, ____, and Unicode.
 a. NRZ-L c. ASCII b. 4B/5B d. NRZI

ANS:  C                    PTS:   1                    REF:   51

1. ____ is an 8-bit code allowing 256 possible combinations of textual symbols.
 a. EBCDIC c. NRZI b. Unicode d. UTF-9

ANS:  A                    PTS:   1                    REF:   51

1. The ____ is a government standard in the United States.
 a. UTF-8 b. EBCDIC c. American Standard Code for Information Interchange (ASCII) d. Unicode

ANS:  C                    PTS:   1                    REF:   52

1. The ASCII character set exists in a few different forms, including a ____ version that allows for 128 possible combinations of textual symbols.
 a. 3-bit c. 6-bit b. 5-bit d. 7-bit

ANS:  D                    PTS:   1                    REF:   52

1. The Unicode character set uses ______ bit characters.
 a. 4 c. 16 b. 8 d. 32

ANS:  C                    PTS:   1                    REF:   53

COMPLETION

1. Converting analog data to digital signals is generally called ____________________.

ANS:  digitization

PTS:   1                    REF:   29

1. ____________________ are the electric or electromagnetic impulses used to encode and transmit data.

ANS:  Signals

PTS:   1                    REF:   30

1. ____________________ is unwanted electrical or electromagnetic energy that degrades the quality of signals and data.

ANS:  Noise

PTS:   1                    REF:   31

1. The ____________________ of a signal is the height of the wave above (or below) a given reference point.

ANS:  amplitude

PTS:   1                    REF:   33

1. The ____________________, or time interval, of one cycle is called its period.

ANS:  length

PTS:   1                    REF:   33

1. The range of frequencies that a signal spans from minimum to maximum is called the ____________________.

ANS:  spectrum

PTS:   1                    REF:   34

1. The ____________________ of a signal is the absolute value of the difference between the lowest and highest frequencies.

ANS:  bandwidth

PTS:   1                    REF:   34

1. Because extraneous noise degrades original signals, an electronic device usually has a(n) ____________________ that is less than its bandwidth.

ANS:  effective bandwidth

PTS:   1                    REF:   34

1. The ____________________ of a signal is the position of the waveform relative to a given moment of time, or relative to time zero.

ANS:  phase

PTS:   1                    REF:   34

1. ____________________ is a relative measure of signal loss or gain and is used to measure the logarithmic loss or gain of a signal.

ANS:

Decibel (dB)

Decibel

dB

PTS:   1                    REF:   35

1. ____________________ is the opposite of attenuation.

ANS:  Amplification

PTS:   1                    REF:   35

1. The ____________________ digital encoding scheme transmits 1s as zero voltages and 0s as positive voltages.

ANS:

NRZ-L

PTS:   1                    REF:   39

1. With the ____________________ encoding scheme, to transmit a 1, the signal changes from low to high in the middle of the interval; to transmit a 0, the signal changes from high to low in the middle of the interval.

ANS:  Manchester

PTS:   1                    REF:   40

1. The ____________________ encoding scheme takes 4 bits of data, converts the 4 bits into a unique 5-bit sequence, and encodes the 5 bits using NRZI.

ANS:  4B/5B

PTS:   1                    REF:   42

1. ____________________ is a simpler form of modulation in which binary 1s and 0s are represented by uniquely different values of amplitude, frequency, or phase.

ANS:  Shift keying

PTS:   1                    REF:   43

1. ____________________ shift keying uses two different frequency ranges to represent data values of 0 and 1.

ANS:  Frequency

PTS:   1                    REF:   44

1. ____________________ is a phenomenon that occurs when the frequencies of two or more signals mix together and create new frequencies.

ANS:  Intermodulation distortion

PTS:   1                    REF:   44

1. A(n) ____________________ converts the analog data to a digital signal by tracking the analog waveform and taking “snapshots” of the analog data at fixed intervals.

ANS:  codec

PTS:   1                    REF:   46

1. Quantization error, or ____________________, causes the regenerated analog data to differ from the original analog data.

ANS:  quantization noise

PTS:   1                    REF:   48

1. A problem inherent with delta modulation is that if the analog waveform rises or drops too quickly, the codec may not be able to keep up with the change, and ____________________ results.

PTS:   1                    REF:   49

1. The set of all textual characters or symbols and their corresponding binary patterns is called a(n) ____________________.

ANS:  data code

PTS:   1                    REF:   49

1. The control character ____________________ (LF) provides control between a processor and an input/output device.

ANS:  linefeed

PTS:   1                    REF:   51

1. The control character ____________________ (CR) provides control between a processor and an input/output device.

ANS:  carriage return

PTS:   1                    REF:   51

1. ____________________ is an encoding technique that provides a unique coding value for every character in every language, no matter what the platform.

ANS:  Unicode

PTS:   1                    REF:   53

1. Currently, ____________________ supports more than 110 different code charts (languages and symbol sets).

ANS:  Unicode

PTS:   1                    REF:   53

ESSAY

1. What are the four possible data-to-signal conversion combinations?

ANS:

Data and signals are two of the basic building blocks of any computer network. It is important to understand that the terms “data” and “signal” do not mean the same thing, and that in order for a computer network to transmit data, the data must first be converted into the appropriate signals. The one thing data and signals have in common is that both can be in either analog or digital form, which gives us four possible data-to-signal conversion combinations:

* Analog data-to-analog signal, which involves amplitude and frequency modulation techniques

* Digital data-to-digital signal, which involves encoding techniques

* Digital data-to-discrete analog signal, which involves modulation techniques

* Analog data-to-digital signal, which involves digitization techniques

PTS:   1                    REF:   28

1. What are common examples of data?

ANS:

Common examples of data include:

* A computer file of names and addresses stored on a hard disk drive

* The bits or individual elements of a movie stored on a DVD

* The binary 1s and 0s of music stored on a compact disc or inside an iPod

* The dots (pixels) of a photograph that has been digitized by a digital camera and stored on a memory stick

* The digits 0 through 9, which might represent some kind of sales figures for a business

PTS:   1                    REF:   29-30

1. What are common examples of signals?

ANS:

Common examples of signals include:

* A transmission of a telephone conversation over a telephone line

* A live television news interview from Europe transmitted over a satellite system

* A transmission of a term paper over the printer cable between a computer and a printer

PTS:   1                    REF:   30

1. What happens when you introduce noise into digital data and digital signals?

ANS:

Noise has the properties of an analog waveform and thus can occupy an infinite range of values; digital waveforms occupy only a finite range of values. When you combine analog noise with digital waveform, it is fairly easy to separate the original digital waveform from the noise.

If the amount of noise remains low enough that the original digital waveform can still be interpreted, then the noise can be filtered out, thereby leaving the original waveform. If, however, the noise becomes so great that it is no longer possible to distinguish a high from a low, then the noise has taken over the signal and you can no longer understand this portion of the waveform.

PTS:   1                    REF:   31

1. What is the purpose of using digital encoding schemes?

ANS:

To transmit digital data using digital signals, the 1s and 0s of the digital data must be converted to the proper physical form that can be transmitted over a wire or airwave. Thus, if you wish to transmit a data value of 1, you could do this by transmitting a positive voltage on the medium. If you wish to transmit a data value of 0, you could transmit a zero voltage. You could also use the opposite scheme: a data value of 0 is positive voltage, and a data value of 1 is a zero voltage. Digital encoding schemes like this are used to convert the 0s and 1s of digital data into the appropriate transmission form. There are six digital encoding schemes that are representative of most digital encoding schemes: NRZ-L, NRZI, Manchester, differential Manchester, bipolar-AMI, and 4B/5B.

Chapter 4: Making Connections

TRUE/FALSE

1. On occasion, a company will create a protocol that, while not an official standard, becomes so popular that other companies start using it.

ANS:  T                    PTS:   1                    REF:   103

1. One of the latest interface standards is the RS-232 interface.

ANS:  F                    PTS:   1                    REF:   104

1. An EIA-232F interface is a full-duplex connection.

ANS:  T                    PTS:   1                    REF:   104

1. Because USB provides a digital interface, it is necessary to convert the digital signals of the microcomputer to analog signals for transfer over a connection.

ANS:  F                    PTS:   1                    REF:   104

1. When using peripherals that are designed with a USB connector, it is also possible to connect one USB peripheral to another.

ANS:  T                    PTS:   1                    REF:   105

1. USB is an example of a full-duplex connection.

ANS:  F                    PTS:   1                    REF:   105

1. The procedural component of USB is probably the most involved of the four components.

ANS:  T                    PTS:   1                    REF:   106

1. FireWire is similar to USB in that it is hot pluggable.

ANS:  T                    PTS:   1                    REF:   106

1. To take advantage of the higher-speed interface of SCSI, you need to install a SCSI adapter in your computer.

ANS:  T                    PTS:   1                    REF:   107

1. Rather than being a single shared bus, InfiniBand is a network of high-speed links and switches.

ANS:  T                    PTS:   1                    REF:   107

1. An asynchronous connection is the most complex example of a data link protocol.

ANS:  F                    PTS:   1                    REF:   108

1. A start bit is always a 1.

ANS:  F                    PTS:   1                    REF:   109

1. A stop bit is always a 0.

ANS:  F                    PTS:   1                    REF:   109

1. The starting and ending sequences of the synchronous connection are called flags.

ANS:  T                    PTS:   1                    REF:   109

1. Because of their higher efficiency, asynchronous connections have almost completely replaced synchronous connections.

ANS:  F                    PTS:   1                    REF:   110

1. Examples of real-time applications usually include streaming voice, video, and music.

ANS:  T                    PTS:   1                    REF:   111

1. Neither USB nor FireWire support isochronous connections.

ANS:  F                    PTS:   1                    REF:   111

1. If control simplicity is your primary goal, point-to-point connection of terminals is clearly superior to multipoint connections.

ANS:  T                    PTS:   1                    REF:   112

1. The Thunderbolt interface is an older interface designed for mainframe computers.

ANS:  F                    PTS:   1                    REF:   107

MULTIPLE CHOICE

1. The connection to a peripheral is often called the ____.
 a. USB c. FireWire b. interface d. EIA-232F

ANS:  B                    PTS:   1                    REF:   104

1. 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                    PTS:   1                    REF:   103-104

1. 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                    PTS:   1                    REF:   103-104

1. 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                    PTS:   1                    REF:   103-104

1. 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                    PTS:   1                    REF:   104

1. 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                    PTS:   1                    REF:   104

1. In modem interfacing terminology, the modem is referred to as the ____.
 a. data communicating equipment (DCE) c. data transmitting equipment (DTE) b. data terminating equipment (DTE) d. data receiving equipment (DRE)

ANS:  A                    PTS:   1                    REF:   104

1. To define functional and procedural components, EIA-232F incorporates the ITU’s ____ standard.
 a. ISO 2110 c. RS-232 b. V.28 d. V.24

ANS:  D                    PTS:   1                    REF:   104

1. A ____ connection is one in which both sender and receiver may transmit at the same time.
 a. full-duplex c. single-duplex b. half-duplex d. multi-duplex

ANS:  A                    PTS:   1                    REF:   105

1. 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                    PTS:   1                    REF:   105

1. 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                    PTS:   1                    REF:   104

1. The ____ component of USB strictly specifies the exact dimensions of the interface’s connectors and cabling.
 a. procedural c. mechanical b. functional d. electrical

ANS:  C                    PTS:   1                    REF:   105

1. A(n) ____ is simply a high-speed connection to which multiple devices can attach.
 a. pin c. circuit b. bus d. interface

ANS:  B                    PTS:   1                    REF:   105

1. FireWire supports two types of data connections: an asynchronous connection and a(n) ____ connection.
 a. synchronous c. parallel b. timed d. isochronous

ANS:  D                    PTS:   1                    REF:   106

1. ____ 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                    PTS:   1                    REF:   107

1. SCSI is a ____ interface and not just an interface technique for hard disk drives.
 a. systems c. server b. terminal d. driver

ANS:  A                    PTS:   1                    REF:   107

1. You can connect up to ____ different SCSI devices to one SCSI adapter.
 a. 2 c. 6 b. 4 d. 7

ANS:  D                    PTS:   1                    REF:   107

1. ____ is a serial connection or bus that can carry multiple channels of data at the same time.
 a. InfiniBand c. SCSI b. Fibre Channel d. USB

ANS:  A                    PTS:   1                    REF:   107-108

1. InfiniBand can support data transfer speeds of ____ per second.
 a. 1.5 billion bits (1.5 gigabits) c. 5 billion bits (5 gigabits) b. 2.5 billion bits (2.5 gigabits) d. 10 billion bits (10 gigabits)

ANS:  D                    PTS:   1                    REF:   107-108

1. InfiniBand can address (interconnect) ____ of devices, using both copper wire and fiber-optic cables.
 a. tens c. thousands b. hundreds d. millions

ANS:  C                    PTS:   1                    REF:   107-108

1. Fibre Channel can support the interconnection of up to ____ devices only.
 a. 56 c. 256 b. 126 d. 512

ANS:  B                    PTS:   1                    REF:   108

1. 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                    PTS:   1                    REF:   109

1. 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                    PTS:   1                    REF:   109

1. With a(n) ____ connection, the unit of transmission is a sequence of characters.
 a. asynchronous c. synchronous b. parity d. serial

ANS:  C                    PTS:   1                    REF:   110

1. 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                    PTS:   1                    REF:   112

1. During the early years of computing, a mainframe computer was called the ____.
 a. secondary c. dumb end b. terminal d. primary

ANS:  D                    PTS:   1                    REF:   112

1. During the early years of computing, a terminal was called the ____.
 a. secondary c. dumb end b. terminal d. primary

ANS:  A                    PTS:   1                    REF:   112

1. 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                    PTS:   1                    REF:   113

1. With ____ connections, polling is not necessary because there is only one terminal per line.
 a. point-to-point c. terminal-to-point b. multipoint d. primary-to-point

ANS:  A                    PTS:   1                    REF:   113

1. 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                    PTS:   1                    REF:   114

1. 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                    PTS:   1                    REF:   107

COMPLETION

1. The process of providing all the proper interconnections between a computer and a peripheral is called ____________________.

ANS:  interfacing

PTS:   1                    REF:   103

1. The ____________________ component of an interface deals with voltages, line capacitance, and other electrical issues.

ANS:  electrical

PTS:   1                    REF:   103

1. The ____________________ component of an interface describes the function of each pin that is used in a particular interface.

ANS:  functional

PTS:   1                    REF:   103

1. ____________________ is an interface standard for connecting a computer or terminal (or DTE) to a voice-grade modem (or DCE) for use on analog public telecommunications systems.

ANS:  EIA-232F

PTS:   1                    REF:   104

1. A(n) ____________________ is the signal that is transmitted over a wire and is related to a particular pin in a connector.

ANS:  interchange circuit

PTS:   1                    REF:   104

1. ____________________ is a digital interface that uses a standardized connector (plug) for all serial and parallel type devices.

ANS:

Universal Serial Bus (USB)

Universal Serial Bus

USB

PTS:   1                    REF:   104

1. The technique of connecting a device to each subsequent device (instead of back to the computer) is known as ____________________.

ANS:  daisy-chaining

PTS:   1                    REF:   105

1. ____________________ is a process in which a computer asks a peripheral if it has any data to transmit to the computer.

ANS:  Polling

PTS:   1                    REF:   112

1. ____________________ is an easy-to-use, flexible, and low-cost digital interface that is capable of supporting transfer speeds of up to 3.2 Gbps.

ANS:  FireWire

PTS:   1                    REF:   106

1. ____________________ connection provides guaranteed data transport at a predetermined rate.

ANS:  Isochronous

PTS:   1                    REF:   109

1. ____________________ is a technique for interfacing disk storage to a computer via the Internet.

ANS:

Internet SCSI (iSCSI)

iSCSI

PTS:   1                    REF:   107

1. ____________________ is similar to InfiniBand in that it too is a serial, high-speed network that connects a computer to multiple input/output devices.

ANS:  Fibre Channel

PTS:   1                    REF:   107-108

1. In a(n) ____________________ connection, a single character, or byte of data, is the unit of transfer between the sender and receiver.

ANS:  asynchronous

PTS:   1                    REF:   108-109

1. To prepare a data character for an asynchronous transmission, a few extra bits of information are added to the data bits of the character to create a(n) ____________________.

ANS:  frame

PTS:   1                    REF:   109

1. A(n) ____________________ bit performs an error check on only the data bits.

ANS:  parity

PTS:   1                    REF:   109

1. A(n) ____________________ connection is a special kind of data link connection used to support various types of real-time applications.

ANS:  isochronous

PTS:   1                    REF:   110

1. A(n) ____________________ connection is a single wire with the mainframe connected on one end and multiple terminals connected on the other end.

ANS:  multipoint

PTS:   1                    REF:   112

1. A technique called ____________________, which allows only one terminal to transmit at one time, successfully controls multiple terminals that share a connection to a mainframe computer.

ANS:  polling

PTS:   1                    REF:   112

1. ____________________ polling is the polling method in which the mainframe computer (primary) polls each terminal (secondary), one at a time, in round-robin fashion.

ANS:  Roll-call

PTS:   1                    REF:   112

1. In ____________________, the primary creates a packet of data with the address of the intended terminal and transmits the packet.

ANS:  selection

PTS:   1                    REF:   113

ESSAY

1. What are the primary organizations involved in making interface standards?

ANS:

The primary organizations involved in making standards are:

* International Telecommunication Union (ITU), formerly the Consultative Committee on International Telegraphy and Telephony (CCITT)

* Electronic Industries Association (EIA)

* Institute for Electrical and Electronics Engineers (IEEE)

* International Organization for Standardization (ISO)

* American National Standards Institute (ANSI)

PTS:   1                    REF:   103

1. What are the standards that conform the EIA-232F interface standard?

ANS:

The EIA-232F interface standard is actually a composite of several other standards: the ITU V.28 standard, which defines EIA-232F’s electrical component; the ISO 2110 standard, which defines the mechanical component; and the ITU V.24 standard, which defines the functional and procedural components.

The electrical component of EIA-232F incorporates ITU’s V.28 standard, which describes the electrical characteristics for a connection between the DTE and DCE. With the V.28 standard, voltage levels are detected at the receiving DCE (modem) by the relative voltage difference between two different wires. A voltage difference of more than +3 volts is considered to be a value of binary 1, and a voltage difference of more negative than –3 volts is considered to be a value of binary 0.

EIA-232F incorporates the ISO 2110 standard to define its mechanical component. ISO 2110 precisely defines the size and configuration of a 25-pin connector (DB-25). More recently, computers have been using a smaller connector, the DB-9.

PTS:   1                    REF:   104

1. What was the early disadvantage of USB?

ANS:

An early disadvantage of USB, at least when compared to other high-speed interfaces (such as FireWire), was its relatively slow speed. USB version 1.1 has a maximum transfer speed of 12 Mbps, significantly slower than FireWire’s 400 Mbps. Fortunately, USB version 2.0 has a maximum transfer speed of 480 Mbps and is backwards compatible with the earlier 1.1 version, allowing devices with the newer interface to connect with the older interface (but at the 12-Mbps speed). More precisely, USB 2.0 can support low-speed (10 to 100 kbps) devices such as keyboards, mice, and game peripherals; full-speed (500 kbps to 10 Mbps) devices such as telephone circuits, audio, and compressed video; and high-speed devices (speeds greater than 10 Mbps) such as video, imaging devices, and broadband.

PTS:   1                    REF:   104-106

ANS:

An asynchronous connection has advantages and disadvantages. On the positive side, generation of the start, stop, and parity bits is simple and requires little hardware or software. On the negative side, an asynchronous connection has one disadvantage in particular that cannot be overlooked. Given that seven data bits (ASCII character code set) are often combined with one start bit, one stop bit, and one parity bit, the resulting transmitted character contains three check bits and seven data bits, for a 3:7 ratio. In this scenario of 10 total check and data bits, 3 out of 10—or 30 percent—of the bits are used as check bits. This ratio of check bits to data bits is not very efficient for high amounts of data transfer and, therefore, results in slow data transfers.

PTS:   1                    REF:   108-110

1. What are the three ways used to maintain synchronization in synchronous connections?

ANS:

Three ways are used to maintain synchronization in synchronous connections:

1. Send a synchronizing clock signal over a separate line that runs parallel to the data stream. As the data arrives on one line, a clock signal arrives on a second line. The receiver can use this clock signal to stay synchronized with the incoming data.
2. If transmitting a digital signal, use a Manchester code. Because a Manchester code always has a signal transition in the middle of each bit, the receiver can anticipate this signal transition and read the incoming data stream with no errors. A Manchester-encoded digital signal is an example of a self-clocking signal.
3. If transmitting an analog signal, use the properties of the analog signal itself for self-clocking. For example, an analog signal with a periodic phase change can provide the necessary synchronization.

PTS:   1                    REF:   110

1. Mainframe computers use polling to send or collect data with workstations.  How does polling work, and what other more recently created protocols use polling?

ANS:

Primary device sends a request to each secondary device in some order, asking each secondary device if it has something to submit to the primary device.  Newer protocols that use polling include USB, FireWire, and Thunderbolt.

PTS:   1                    REF:   111-113

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