CH 3

Question 1

____________ is used by IM and other applications that provide voice services over lower-speed digital circuits.

Answer 1

adaptive differential pulse code modulation

Question 2

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

Answer 2

False

Question 3

Time (non-statistical) division multiplexing differs from frequency division multiplexing because it:

A) does not share a communication circuit

B) splits the communication circuit vertically (with time slots) instead of horizontally

C) increases the wavelength and phase angles of the baseband frequency used for transmission

D) moves the baseband of a circuit by shifting it to a higher frequency

E) reduces baseband signal velocity more than frequency division multiplexing

Answer 3

B) splits the communication circuit vertically (with time slots) instead of horizontally

Question 4

Digital transmission produces more errors than analog transmission.
t or f

Answer 4

False

Question 5

Digital transmission permits higher maximum transmission rates when compared to analog.
t or f

Answer 5

True

Question 6

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

Answer 6

False

Question 7

_____________ can be thought of as dividing the circuit horizontally.

Frequency division multiplexing
Statistical frequency division multiplexing
Statistical time division multiplexing
Time division multiplexing
Wavelength division multiplexing

Answer 7

Frequency division multiplexing

Question 8

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

Answer 8

physical

Question 9

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.
T or F

Answer 9

F

Question 10

A(n) ___________ divides one high-speed communication circuit into several lower speed circuits for the primary reason of saving communication line costs.

transponder
multiplexer
inverse multiplexer
codec
intelligent terminal

Answer 10

multiplexer

Question 11

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

phase
attenuation
bipolar
bandwidth
codec

Answer 11

phase

Question 12

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

synchronous time division
amplitude shift keying
amplitude modulation
frequency modulation
phase modulation

Answer 12

synchronous time division

Question 13

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

international
level 1
numeric
analog
digital

Answer 13

digital

Question 14

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

unipolar
serial
bipolar
attenuation
Huffman encoding signal

Answer 14

bipolar

Question 15

A _________ is an FDM device that splits the physical circuit into three logical circuits (phone, upstream data, downstream data).

DSL modem
cable modem
wireless router
V.44 modem
Serial modem

Answer 15

DSL modem

Question 16

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

digital coding
phase modulation
binary modulation
analog transmission
pitch variation

Answer 16

digital coding

Question 17

Based on the TIA/EIA 568-B structured cabling standard, the cabling that runs from the telecommunications closet to each work area is called backbone cabling.

True or False

Answer 17

F

Question 18

In general, older networks and local loops designed to transmit voice data are likely to be ________.

international
level 2
numeric
digital
analog

Answer 18

analog

Question 19

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

T or F

Answer 19

T

Question 20

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.

Answer 20

D) Serial transmission is slower than parallel transmission.

Question 21

Signal bandwidth is the difference between the highest and lowest frequencies in a band.

T or F

Answer 21

T

Question 22

Fiber optic cable can only be used on LANs.

T or F

Answer 22

F

Question 23

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

Line-of-sight effect
Multimode index
Saturation effect
Raindrop attenuation
Propagation delay

Answer 23

Propagation delay

Question 24

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

Answer 24

T

Question 25

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

Answer 25

F

Question 26

Equipment used to transform analog voice signals to digital signals and digital signals to analog signals. ``` voice converter modem codec multiplexer demodulator ```

Answer 26

codec ?

Question 27

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

Answer 27

F

Question 28

A(n) ___________ divides one high-speed communication circuit into several lower speed circuits for the primary reason of saving communication line costs. ``` transponder multiplexer inverse multiplexer codec intelligent terminal ```

Answer 28

multiplexer

Question 29

A coding scheme that uses 10 bits to represent each character is capable of representing _________ different characters. Group of answer choices ``` 256 20 200 512 1024 ```

Answer 29

1024

Question 30

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

Answer 30

T

Question 31

In full-duplex transmission, two stations can send and receive simultaneously. T or F

Answer 31

T

Question 32

ASCII is the least popular code for data communications. | T or F

Answer 32

F

Question 33

___________ refers to the spreading of the signal that different parts of the signal arrive at different times at the destination. ``` turnaround time propagation delay dispersion insulation attenuation ```

Answer 33

dispersion

Question 34

Having a conversation with someone using a cellular phone is an example of _________ transmission. ``` simplex full-duplex half-duplex analog digital ```

Answer 34

full-duplex

Question 35

______ is a modem standard that uses Lempel-Ziv encoding to compress data. ``` V.22 V.44 V.32bis V.34 RS 232 ```

Answer 35

V.44

Question 36

The type of multiplexer that divides the circuit horizontally into different light frequencies that are transmitted simultaneously across many channels is a: ``` wavelength division multiplexer time division multiplexer statistical time division multiplexer frequency division multiplexer statistical frequency division multiplexer ```

Answer 36

wavelength division multiplexer

Question 37

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

Answer 37

T

Question 38

Two fundamentally different types of data are: ``` DSL and ADSL asymmetric and symmetric Microsoft and IBM digital and analog local area and wide area ```

Answer 38

digital and analog

Question 39

WDM is a version of FDM used in fiber-optic cables. | T or F

Answer 39

T

Question 40

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

Answer 40

T

Question 41

In which type of modulation is a 1 distinguished from a 0 by shifting the direction in which the wave begins? ``` bandwidth modulation amplitude modulation frequency modulation phase modulation codec modulation ```

Answer 41

phase modulation

Question 42

_____________ refers to the difference between the original analog data and the approximation of that data using the techniques for translating from analog data to digital signals. Group of answer choices ``` quantizing error handshaking phase modulating frequency POTS anomaly amplitude Trellis effect ```

Answer 42

quantizing error

Question 43

Another term for the weakening of a signal over distance is: ``` turnaround time propagation delay dispersion insulation attenuation ```

Answer 43

attenuation

Question 44

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

Answer 44

T

Question 45

Data compression can increase the throughput of a communication link. T or F

Answer 45

T

Question 46

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 or F

Answer 46

T

Question 47

The room that contains the cable termination points and the distribution frames is referred to as ``` telecommunications closet equipment room building entrance backbone room work area ```

Answer 47

Telecommunications Closet

Question 48

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

Answer 48

T

Question 49

The direction in which the sound wave begins is known as: amplitude, which our ears detect as loudness frequency, which our ears detect as pitch phase bandwidth furlong

Answer 49

phase

Question 50

With respect to converting digital data into analog signals, AM stands for: Group of answer choices ``` Asynchronous Manchester Analog Multimode Amplitude Modulation Anomaly Multiplexing Analytical Mosaic ```

Answer 50

Amplitude Modulation

Question 51

When sending four bits at a time using frequency modulation, the number of different frequency levels that would be needed would be _______. Group of answer choices ``` 24 16 2 8 4 ```

Answer 51

16

Question 52

The typical range of human hearing is: Group of answer choices ``` 0 to 4,000 Hz 0 to 1,200 Hz 20 to 14,000 Hz 0 to 300 Hz 0 to 56,000 Hz ```

Answer 52

20 to 14,000 Hz

Question 53

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

Answer 53

T

Question 54

____________ is a modulation technique that combines two different amplitude combinations with eight different phase combinations modulation to send four bits per symbol. ``` quadrature amplitude modulation time division multiplexing synchronous digital line control pulse code modulation baseband signaling ```

Answer 54

quadrature amplitude modulation

Question 55

When all bits of a character are transferred one after another, the bits are transferred in ___________ mode. ``` serial frequency division multiplexing parallel full complex ```

Answer 55

serial