Chapter 3

Front 1

Attenuation

Back 1

excessive cable weakening

Front 2

dispersion

Back 2

spreading of the signal so that different parts of the signal arrive at different times at the destination

Front 3

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

Back 3

False- frequency is measured by number of waves per second

Front 4

If each sample uses 16 bits and the number of samples taken each second is 8000; then the transmission speed on the circuit is?

Back 4

128 Kbps

Front 5

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

Back 5

False- single mode transmits a single light beam resulting in faster and longer distances

Front 6

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

Back 6

Quadrature Amplitude Modulation

Front 7

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

Back 7

False- Because it is shared, only one computer can use the circuit at a time

Front 8

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

Back 8

False- reach positive and negative values to represent on and off

Front 9

_________ is the basic physical layout of the circuit.

Back 9

Circuit Configuration

Front 10

Propagation delay is negligible with satellite transmission.

Back 10

False- Propagation delay is a disadvantage to satellite b/c the signal has to ravel out into space and back to earth, that is noticeable eve at the speed of light

Front 11

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

Back 11

adaptive differential pulse code modulation (ADPCM)

Front 12

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

Back 12

True- used to transfer binary info within computer

Front 13

Fiber optic cable carries signals in traditional electrical form

Back 13

False- uses high-speed streams of light pulses from lasers or LEDs that carry info inside hair-thin strands of glass called optical fibers

Front 14

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

Back 14

Return-to-zero signaling

Front 15

The earliest type of fiber optic systems were:

Back 15

Multimode (step index then graded)

Front 16

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

Back 16

Twisted Pair

Front 17

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

Back 17

Shared

Front 18

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

Back 18

False- only two states 0 and 1

Front 19

Digital transmission produces more errors than analog transmission.

Back 19

False

Front 20

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

Back 20

False- Multiplexing

Front 21

The typical range of human hearing is:

Back 21

20-14,000 Hz

Front 22

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

Back 22

Microwave

Front 23

Which of the following statements is correct?

Back 23

Serial transmission is slower than parallel transmission.

Front 24

Transmission speeds:

Back 24

differ widely among media

Front 25

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

Back 25

False- converts incoming analog signal to a digital

Front 26

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

Back 26

fiber optic cable?

Front 27

A physical circuit refers to the transmission characteristics of the connection.

Back 27

False

Front 28

Nonreturn to zero is a type of unipolar signaling

Back 28

False- Bipolar

Front 29

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

Back 29

True

Front 30

ASCII is the least popular code for data communications.

Back 30

False

Front 31

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

Back 31

Propagation delay

Front 32

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

Back 32

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

Front 33

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

Back 33

True

Front 34

The cabling that runs from the telecommunications closet to each LAN is called backbone cabling.

Back 34

False

Front 35

WDM is a version of FDM used in fiber-optic cables.

Back 35

True

Front 36

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

Back 36

bipolar

Front 37

__________ refers to the transmission characteristics of the circuit

Back 37

logical circuit

Front 38

Coding schemes are groups of bits that translate into the "alphabet" of any given system.

Back 38

True

Front 39

Baud rate is the number of bits transmitted per second.

Back 39

False- the number of of times per second the signal on the communication circuit changes

Front 40

Data compression can increase the throughput of a communication link.

Back 40

True

Front 41

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

Back 41

True

Front 42

The acronym, Modem, stands for _________________.

Back 42

Modulator/demodulator

Front 43

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

Back 43

Serial

Front 44

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

Back 44

modulation

Front 45

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

Back 45

phase modulation

Front 46

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

Back 46

bandwidth

Front 47

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

Back 47

digital

Front 48

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

Back 48

False-divides circuit horizontally into series of separate channels

Front 49

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

Back 49

True

Front 50

Radio, microwave and satellite are all examples of guided media.

Back 50

False-Wireless media

Front 51

Ethernet, a common LAN technology, uses Manchester encoding.

Back 51

True

Front 52

Which of the following is the most secure wired media?

Back 52

Fiber Optic

Front 53

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

Back 53

Full-duplex

Front 54

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

Back 54

16

Front 55

Microwave transmission:

Back 55

is a type of high frequency radio communication, requires a clear line-of-sight pathis typically used for long distance data transmission, does not require the laying of any cable, all of the above

Front 56

Which of the following statements is true?

Back 56

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

Front 57

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

Back 57

True

Front 58

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

Back 58

Attenuation

Front 59

___________ is not a type of digital signaling technique.

Back 59

Data rate signaling

Front 60

The room that contains the cable termination points and the distribution frames is referred to as

Back 60

telecommunications closet

Front 61

_____________ 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.

Back 61

quantizing error