Deck 5: Making Connections Efficient: Multiplexing and Compression

Question 1

The data rate of OC-3 is exactly thirty times the rate of OC-1.

Answer 1

False

Question 2

Cell phones are an example of dynamically assigned channels.

Answer 2

True

Question 3

Dense wavelength division multiplexing is an expensive way to transmit signals from multiple devices due to the high number of differently colored lasers required in one unit.

Answer 3

True

Question 4

Time division multiplexing (TDM) allows only one user at a time to transmit.

Question 5

Wavelength division multiplexing (WDM) is, in essence, a time division multiplexing technique.

Question 6

Multiplexing is a technique typically performed at the network access layer of the TCP/IP protocol suite.

Question 7

The STS multiplexor in a SONET network can accept electrical signals from copper-based media.

Question 8

The T-1's original purpose was to provide a high-speed connection between AT&T's switching centers.

Question 9

The T-1 system is a classic application of frequency division multiplexing.

Question 10

Both frequency division multiplexing and synchronous time division multiplexing can waste unused transmission space.

Question 11

A T-1 system sends the equivalent of 24 voice grade telephone lines over one line.

Question 12

SONET is a more modern term for the older T-1 system.

Question 13

SONET and SDH are able to multiplex varying speed streams of data onto one fiber connection.

Question 14

A T-1 system continuously sends a signal, even if there is no real data to transmit.

Question 15

Frequency division multiplexing is the latest multiplexing technique.

Question 16

WDM supports multiple lambdas.

Question 17

One way to make a connection between two devices more efficient is to compress the data that transfers over the connection.

Question 18

As with a simple connection between one sending device and one receiving device, maintaining synchronization across a multiplexed link is important.

Question 19

In frequency division multiplexing, the combined signals are digital.

Question 20

SDH was developed in Europe by ITU-T.

Question 21

The basic way to perform compression is to look for some common pattern in the data and replace each data pattern with a symbol or symbols that will consume less space during transmission or storage.

Question 22

Under normal circumstances, the synchronous time division multiplexor maintains a simple ____ sampling order of the input devices.

A)round-robin
B)FIFO
C)LIFO
D)FILO

Question 23

The human ear can hear sounds only within a certain range, which for an average person is 10 Hz to 40 kHz (40,000 Hz).

Question 24

____ gives each incoming source signal a turn to be transmitted, proceeding through the sources in round-robin fashion.

A)Statistical time division multiplexing (Stat TDM)
B)Empirical time division multiplexing (ETDM)
C)Synchronous time division multiplexing (Sync TDM)
D)Fixed time division multiplexing (FTDM)

Question 25

The Lempel-Ziv algorithm can be fairly effective in compressing data.

Question 26

The MP3 encoder produces a data stream that has a much faster data rate than that of conventional CD-quality music.

Question 27

Presently, a medium can be divided in three basic ways: a division of ____, a division of time, and a division of transmission codes.

A)frequencies
B)amplitudes
C)wavelength
D)direction

Question 28

To allow multiple users to share a single medium, FDM assigns each user a separate ____.

A)time slot
B)transmission code
C)channel
D)amplitude

Question 29

Code division multiplexing is based upon a class of modulation techniques known as spread spectrum technology.

Question 30

The device that is attached to the receiving end of the medium and splits off each signal to deliver it to the appropriate receiver is called the second multiplexor, or ____.

A)multiplexor
B)endplexor
C)splitxor
D)demultiplexor

Question 31

Code division multiplexing, while using a fairly wide bandwidth of frequencies and a complex technology, is scalable like WDM.

Question 32

Since time division multiplexing was introduced, it has split into two roughly parallel but separate technologies: synchronous time division multiplexing and ____ time division multiplexing.

A)fixed
B)statistical
C)inverse
D)empirical

Question 33

DSL is capable of achieving speeds into the millions of bits per second.

Question 34

The big advantage of frequency division multiplexing over synchronous TDM is the lower noise due to the use of digital signals during transmission.

Question 35

First-generation cellular telephone systems allocated channels using frequency ranges within the 800 to ____ megahertz (MHz) spectrum.

A)830
B)900
C)930
D)960

Question 36

____ is the assignment of nonoverlapping frequency ranges to each "user" of a medium.

A)Time division multiplexing (TDM)
B)Transmission code multiplexing (TCM)
C)Amplitude division multiplexing (ADM)
D)Frequency division multiplexing (FDM)

Question 37

In FDM, ____ take up frequencies that might be used for other data channels, thus introducing a certain level of wastefulness.

A)guard bands
B)channels
C)multiplexors
D)demultiplexors

Question 38

Synchronous time division multiplexing does not require as high-speed a line as statistical time division multiplexing does.

Question 39

A video device displays multiple (typically 30) frames per second.

Question 40

Three types of synchronous time division multiplexing that are popular today are T-1 multiplexing, ____ multiplexing, and SDH.

A)EIA-232F
B)IPS/SPX
C)SONET
D)RS-232

Question 41

____ uses different wavelength (frequency) lasers to transmit multiple signals at the same time over a single medium.

A)Wave division multiplexing
B)Statistical time division multiplexing
C)Channel division multiplexing
D)Time division multiplexing

Question 42

____ division multiplexing is a good choice for connecting a number of lower-speed devices that do not transmit data on a continuous basis to a remote computer system.

A)Statistical time
B)Time
C)Discrete tone
D)Frequency

Question 43

Code division multiplexing can produce system capacities that are ____ times those of frequency division multiplexing systems.

A)2 to 4
B)3 to 6
C)4 to 8
D)8 to 10

Question 44

____ multiplexes multiple data streams onto a single fiber-optic line.

A)Statistical time division multiplexing (Stat TDM)
B)Wavelength division multiplexing (WDM)
C)Time division multiplexing (TDM)
D)Channel division multiplexing (CDM)

Question 45

SONET defines a hierarchy of signaling levels, or data transmission rates, called ____.

A)statistical transport signals (StatTS)
B)empirical transport signals (ETS)
C)asynchronous transport signals (ATS)
D)synchronous transport signals (STS)

Question 46

It is relatively simple to multiplex four STS-12 signals into one ____ signal.

A)STS-8
B)STS-16
C)STS-32
D)STS-48

Question 47

____ technology is a unique form of multiplexing in that all the subchannels multiplexed together are intended for one user.

A)Time division
B)Discrete multitone
C)Frequency division
D)Code division

Question 48

____ multiplexing is the multiplexing technique used to support SONET.

A)FDM
B)ADM
C)Frequency division
D)Synchronous time division

Question 49

Chip spreading codes are ____ bits in length.

A)32
B)64
C)128
D)256

Question 50

The STS-1 signaling level supports ____ frames per second.

A)8000
B)16000
C)32000
D)64000

Question 51

____ is a technology that allows a high-speed data signal to traverse a standard copper-based telephone line.

A)DSL
B)RS-232
C)EIA-232F
D)FireWire

Question 52

Statistical time division multiplexing is sometimes called ____ time division multiplexing.

A)empirical
B)random
C)asynchronous
D)synchronous

Question 53

____ is the technology behind the popular digital subscriber line (DSL) system.

A)Time division
B)Amplitude division
C)Wavelength division
D)Discrete multitone

Question 54

SONET and SDH are both ____ multiplexing techniques.

A)synchronous
B)statistical
C)empirical
D)random

Question 55

A ____ multiplexes 24 input channels together onto one high-speed telephone line.

A)T-1 system
B)SONET system
C)SDH system
D)congruent system

Question 56

____ is designed for short-distance connections and has only a few lambdas, with a greater space between lambdas.

A)Dense wavelength division multiplexing (DWDM)
B)Fixed wavelength division multiplexing (FWDM)
C)Coarse wavelength division multiplexing (CWDM)
D)Inverse wavelength division multiplexing (IWDM)

Question 57

____ division multiplexing is a good technique for transmitting multiple concurrent signals over a fiber-optic line.

A)Statistical time
B)Synchronous time
C)Frequency
D)Wavelength

Question 58

A T-1 system multiplexes _______ into each frame.

A)a single ASCII character
B)a single LENGTH byte
C)a single SYNC bit
D)a single SYNC byte

Question 59

In the 1960s, AT&T created a service known as ____, which multiplexed digital data and digitized voice onto a high-speed telephone line with a data rate of 1.544 megabits per second.

A)ISDN
B)T-1
C)SONET
D)SDH

Question 60

SONET was developed in the United States by ____.

A)ISO
B)ANSI
C)IEEE
D)IETF

Question 61

The technique of transmitting multiple signals over a single medium is ____________________.

Question 62

____________________, and Synchronous Digital Hierarchy (SDH) are two almost identical standards for the high-bandwidth transmission of a wide range of data types over fiber-optic cable.

Question 63

In general, the device that accepts input from one or more users is called the ____________________.

Question 64

A technique that can be used to compress data when a ____ compression is necessary is the Lempel-Ziv technique.

A)random
B)run-length
C)lossy
D)lossless

Question 65

A(n) ____________________ is an assigned set of frequencies that is used to transmit the user's signal.

Question 66

In Stat TDM, the ____________________, provides information that the receiving multiplexor can use to detect transmission errors within the frame.

Question 67

If a compression technique does lose some of the data as a result of the compression process, then it is referred to as a ____ compression technique.

A)complete
B)random
C)lossy
D)lossless

Question 68

A T-1 telecommunications line uses a multiplexing technique termed ____________________, which provides for the multiplexing of up to 24 separate channels at a total speed of 1.544 Mbps.

Question 69

____________________, transmits data only from active users and does not transmit empty time slots.

Question 70

Each STS level supports a particular data rate and is supported by a physical specification called a(n) ____________________.

Question 71

Discrete multitone (DMT) is a multiplexing techinque commonly found in _______ systems.

A)TDM
B)DSL
C)ATM
D)microwave

Question 72

The inability of a single fiber-optic line to meet users' needs is called ____________________.

Question 73

Synchronous Optical Network (SONET) and ____________________, are powerful standards for multiplexing data streams over a single medium.

Question 74

____, which is an abbreviation for MPEG (Moving Picture Experts Group) Audio Layer-3, is a common form of audio compression.

A)MPEG
B)GIF
C)MP3
D)JPEG

Question 75

In ____________________, the sharing of the medium is accomplished by dividing available transmission time among users.

Question 76

____ replaces any repetitions of the same bit or byte that occur in a sequence of data with a single occurrence of the bit/byte and a run count, or simply with a run count.

A)Run-length encoding
B)Lossy compression
C)Random compression
D)Full encoding

Question 77

______ is a technique that is very commonly used to compress video images.

A)JPEG
B)MPEG
C)MP3
D)AAA

Question 78

In ____________________ multiplexing, the frames of the multiplexor's output stream are divided into 24 separate digitized voice/data channels of 64 kbps each.

Question 79

To keep one signal from interfering with another signal, a set of unused frequencies called a(n) ____________________ is usually inserted between the two signals, to provide a form of insulation.

Question 80

MPEG-1 and MPEG-2-or simply MPEG-are common examples of ____ compression.

A)wavelength encoding
B)differential encoding
C)code division
D)frequency encoding