Business Data Communications & Networking 14th edition Chapter 3 Test Bank

The physical layer is a layer where two communicating nodes are directly connected. T/F

T

A physical circuit refers to the transmission characteristics of the connection

F

Computers produce digital data whose values are binary: 0 or 1.

T

With modem communications, the receiving modem converts the incoming digital signal from the telephone line into an analog signal that can be understood by the computer.

F

Digital transmission produces more errors than analog transmission.

F

Newer telephone circuits, built during the last decade, offer higher quality because they were built using analog transmission.

F

In a multipoint circuit configuration, each computer has a dedicated circuit between itself and each of the other computers in the network

F

In a multipoint circuit configuration, each computer can use the circuit at the same time.

F

In simplex transmission, the data flows in both directions at the same time

F

A walkie-talkie is an example of half-duplex transmission.

T

The amount of time it takes to switch between sending and receiving in half-duplex transmission is called the propagation delay.

F

In full-duplex transmission, two stations can send and receive simultaneously

T

The medium is the physical matter or substance that carries the voice or data transmission.

T

Guided media refers to the type of media in which the message is broadcast through the air.

F

Coaxial cable costs less and offers less shielding to electrical interference than twisted pair cable

F

Fiber optic cable carries signals in traditional electrical form

F

Multimode fiber is capable of longer transmission distances than single mode fiber.

F

Radio data transmission requires that each device has a radio receiver/transmitter and uses a specific frequency

T

Frequency division multiplexing is used on twisted-pair cabling.

F

Microwave transmissions require a line of sight between any two points.

T

Propagation delay is negligible with satellite transmission.

F

One form of interference with satellite transmission is called raindrop attenuation in which the transmissions are absorbed by heavy rain.

T

Fiber optic cable can only be used on LANs.

F

Radio, microwave and satellite are all examples of guided media

F

Of all the media available, fiber optic provides the highest transmission speeds.

T

Coding schemes are groups of bits that translate into the “alphabet” of any given system

T

ASCII is the least popular code for data communications.

F

The predominant method of transferring information internally in a computer is via parallel mode

T

Serial mode transmission is much faster than parallel mode transmission.

F

Nonreturn to zero is a type of unipolar signaling

F

With nonreturn to zero signaling, the voltage alternates between zero and a positive or negative voltage

F

Ethernet, a common LAN technology, uses Manchester encoding.

T

Manchester encoding is a special type of bipolar signaling in which the signal is changed from high to low or from low to high in the middle of the signal.

T

Digital transmission occurs when the signal sent over the transmission media constantly varies among an infinite number of states.

F

Frequency is the number of cycles per second and is expressed in Hertz.

T

Amplitude, frequency and phase are all characteristics of a sound wave

T

Frequency modulation refers to the changing of the height of the sound wave.

F

Baud rate is the number of bits transmitted per second

F

Bandwidth is the difference between the highest and lowest frequencies in a band

T

Data compression can increase the throughput of a communication link

T

A codec converts an incoming digital signal to an analog signal for transmission over an analog network.

F

One way to reduce quantizing errors is to increase the sampling rate of the analog signal.

T

The “local loop” refers to the wires that run from the customer premises to the telephone switch of the telephone company

T

Multiplexing increases the cost of provisioning network circuits.

F

Frequency division multiplexing divides the circuit into a set of different time slots.

F

Time division multiplexing is more efficient that frequency division multiplexing because the guardbands used in the frequency division multiplexing or not needed.

T

Statistical time division multiplexing does not require the capacity of the circuit to be equal to the sum of the combined circuits.

T

Wavelength division multiplexing can only used with copper cables.

F

Digital transmission permits higher maximum transmission rates when compared to analog.

T

Multitasking means to break one high-speed physical communication circuit into several lower-speed logical circuits so that different devices can simultaneously use it.

F

Data is physically transmitted from one computer or terminal to another in the ________ layer.

a. physical

b. transport

c. application

d. terminal

e. data link

A

____________ refers to the transmission characteristics of the circuit.

a. handshaking

b. virtual circuit

c. bonding

d. logical circuit

e. physical circuit

D

Two fundamentally different types of data are:

a. DSL and ADSL

b. asymmetric and symmetric

c. Microsoft and IBM

d. digital and analog

e. local area and wide area

D

In general, networks designed to transmit primarily computer data are likely to be ________, while networks designed to transmit voice data are likely to be ________.

a. slow, fast

b. level 1, level 2

c. numeric, musical

d. direct, indirect

e. digital, analog

E

Which of the following is not a key advantage of digital transmission?

a. It permits only low transmission rates.

b. It is more efficient.

c. It is simpler to integrate voice, video, and data on the same circuit.

d. It is more secure. e. It produces fewer errors

A

_________ is the basic physical layout of the circuit.

a. point-to-point configuration

b. configuration

c. circuit configuration

d. circuit design

e. circuit plan

C

A(n) __________ circuit is another name for a multipoint configuration.

a. analog

b. dedicated

c. point-to-point

d. shared

e. simplex

D

Which is not true about point-to-point circuits?

a. point-to-point circuits are dedicated to the use of the two computers.

b. point-to-point circuits are more expensive than multipoint circuits.

c. point-to-point circuits are called dedicated circuits.

d. point-to-point circuits reduce the amount of cable required and use the circuit more efficiently than multipoint circuits.

e. point-to-point circuits are used when the computers generate enough traffic to fill the capacity of the communication circuit.

D

Having a conversation with someone using a cellular phone is an example of _________ transmission.

a. simplex

b. full-duplex

c. half-duplex

d. analog

e. digital

B

The ability to transmit in both directions, but only in one direction at a time is an example of _______________ transmission.

a. simplex

b. full-duplex

c. half-duplex

d. analog

e. digital

C

The two basic types of media are:

a. statistical and frequency

b. guided and wireless (radiated)

c. local and wide area

d. attenuator and Gaussian

e. duplexed and non-duplexed

B

Which of the following would be considered a type of wireless media?

a. unshielded twisted pair

b. shielded twisted pair

c. coaxial cable

d. microwave

e. fiber optics

D

The type of media usually installed on homes and businesses by the telephone company is called ____________.

a. fiber optic cable

b. coaxial cable

c. twisted pair

d. phone cable

e. phone wire

C

The earliest type of fiber optic systems were:

a. Graded index multimode

b. Attenuated

c. Multimode

d. Single mode

e. Step mode

C

Another term for the weakening of a signal over distance is:

a. turnaround time

b. propagation delay

c. dispersion

d. insulation

e. attenuation

E

___________ refers to the spreading of the signal that different parts of the signal arrive at different times at the destination.

a. turnaround time

b. propagation delay

c. dispersion

d. insulation

e. attenuation

C

Which of the following media can best withstand harsh environmental conditions?

a. shielded twisted pair

b. unshielded twisted pair

c. Cat 5 twisted pair

d. coaxial cable

e. fiber optic cable

E

__________ is a line-of-sight type of wireless media.

a. coaxial cable

b. microwave

c. radio

d. twisted pair

e. fiber optic

B

____________ can be thought of as dividing the circuit horizontally.

a. Frequency division multiplexing

b. Statistical frequency division multiplexing

c. Statistical time division multiplexing

d. Time division multiplexing

e. Wavelength division multiplexing

A

Microwave transmission:

a. is a type of high frequency radio communication

b. requires a clear line-of-sight path

c. is typically used for long distance data transmission

d. does not require the laying of any cable

e. all of the above

E

______________ refers to the time it takes for a signal to travel from sender to recipient (highly exaggerated with satellite transmission).

a. Line-of-sight effect

b. Multimode index

c. Saturation effect

d. Raindrop attenuation

e. Propagation delay

E

Which of the following is not an important factor to consider when selecting media to be used in a network?

a. prestige value of the type of media

b. type of network

c. cost

d. transmission distance

e. security

A

Which of the following is the most secure wired media?

a. coaxial cable

b. unshielded twisted pair

c. shielded twisted pair

d. fiber optic cable

e. infrared

D

Which of the following media has the lowest error rates and the highest transmission speeds?

a. Coaxial cable

b. unshielded twisted pair

c. shielded twisted pair

d. fiber optic cable

e. infrared

D

Transmission speeds:

a. are the same among all media

b. are not a factor in selecting a media because all media have more than enough speed to serve current communication demands

c. are a constant, 56Kbps, for all media types

d. differ widely among media

e. always have a direct correlation with security

D

A coding scheme that uses 10 bits to represent each character is capable of representing _________ different characters.

a. 256

b. 20

c. 200

d. 512

e. 1024

E

____________ is one of the most commonly used coding schemes used in data transmission.

a. ASCII

b. ISDN

c. MAU

d. ATM

e. FDM

A

The representation of the character A by the group of 8 bits, 01000001, is an example of:

a. digital coding

b. phase modulation

c. binary modulation

d. analog transmission

e. pitch variation

A

When all bits of a character are transferred one after another, the bits are transferred in ___________ mode.

a. serial

b. frequency division

c. multiplexing

d. parallel

e. full complex

A

Which of the following statements is correct?

a. Parallel transmission is most often used for sending data on a circuit that is made up of one wire.

b. Parallel transmission is distinguished from serial transmission by the fact that the transmitting device sends a single bit, then a second bit, and so on, until all the bits are transmitted.

c. Parallel transmission is only used for analog data.

d. Serial transmission is slower than parallel transmission.

e. Parallel transmission is the same as serial transmission

D

_________ is not a type of digital signaling technique.

a. Non-return-to-zero signaling

b. Unipolar signaling

c. Manchester encoding

d. Return-to-zero signaling

e. Data rate signaling

E

With which type of digital signaling does the signal always return to zero volts after each bit?

a. Non-return-to-zero signaling

b. Unipolar signaling

c. Return-to-zero signaling

d. Data rate signaling

e. Huffman encoding signal

C

Which type of digital signaling would experience fewer errors because it has more distinct signals?

a. unipolar

b. serial

c. bipolar

d. attenuation

e. Huffman encoding signal

C

Which of the following is a characteristic of sound waves that can be modulated to convert digital data into analog signals?

a. phase

b. attenuation

c. bipolar

d. bandwidth

e. codec

A

The direction in which the sound wave begins is known as:

a. amplitude, which our ears detect as loudness

b. frequency, which our ears detect as pitch

c. phase

d. bandwidth

e. furlong

C

The height of a sound wave is called its:

a. frequency

b. phase

c. amplitude

d. bandwidth

e. furlong

C

_____________ is not a form of modulation used to transform digital data into analog signals.

a. synchronous time division

b. amplitude shift keying

c. amplitude modulation

d. frequency modulation

e. phase modulation

A

____________ refers to changing the shape of the sound wave in different ways to represent a 1 or a 0.

a. digitizing.

b. sampling

c. modulation

d. demodulation

e. shaping

C

With respect to converting digital data into analog signals, AM stands for:

a. Asynchronous Manchester

b. Analog Multimode

c. Amplitude Modulation

d. Anomaly Multiplexing

e. Analytical Mosaic

C

In which type of modulation is a 1 distinguished from a 0 by shifting the direction in which the wave begins?

a. bandwidth modulation

b. amplitude modulation

c. frequency modulation

d. phase modulation

e. codec modulation

D

When sending four bits at a time using frequency modulation, the number of different frequency levels that would be needed would be _______.

a. 24

b. 16

c. 2

d. 8

e. 4

B

_________ is a modulation technique that combines two different amplitude combinations with eight different phase combinations modulation to send four bits per symbol.

a. quadrature amplitude modulation

b. time division multiplexing

c. synchronous digital line control

d. pulse code modulation

e. baseband signaling

A

The _____________ of a circuit determines a circuit’s capacity.

a. frequency

b. bandwidth

c. phase

d. amplitude

e. loudness

B

The typical range of human hearing is:

a. 0 to 4,000 Hz

b. 0 to 1,200 Hz

c. 20 to 14,000 Hz

d. 0 to 300 Hz

e. 0 to 56,000 Hz

C

If the highest frequency of a circuit is 10KHZ and the lowest frequency is 900 Hz, the bandwidth available for this circuit is

a. 890 Hz

b. 8900 HZ

c. 9100 Hz

d. 9Khz

e. 890 KHz

C

To get more “bandwidth” in a digital transmission, you must:

a. increase the range of frequencies available for a transmission

b. increase the loudness per transmission

c. decrease the bits per second transmission speed

d. increase the phase shifts per transmission

e. increase the baud rate per transmission

A

Which of the following statements is true?

a. the longer the distance of a telephone wire between sender and recipient, the lower the bandwidth across that wire

b. the shorter the distance of a telephone wire between sender and recipient, the lower the bandwidth across that wire

c. bandwidth is constant across any wire, therefore distance is not relevant to its capacity

d. the longer the distance of a telephone wire between sender and recipient, the higher the bandwidth across that wire

e. bandwidth is not a term that can be used when discussing telephone transmissions

C

The acronym, Modem, stands for _________________.

a. multiplexing/demultiplexing

b. more/demote

c. Mode-M technique

d. modulator/demodulator

e. Mod emulation technique

D

_____ is a modem standard that uses Lempel-Ziv encoding to compress data. a. V.22

b. V.44

c. V.32bis

d. V.34

e. RS 232

B

Equipment used to transform analog voice signals to digital signals and digital signals to analog signals.

a. voice converter

b. modem

c. codec

d. multiplexer

e. demodulator

C