_________ is one way that data rates over traditional telephone lines can be increased dramatically.

_________ is one way that data rates over traditional telephone lines can be increased dramatically.

a. SONET
b. T-carrier services
c. CSU/DSU
d. ATM
e. DSL



Answer: dsl

Digital Subscriber Line:

Digital Subscriber Line:

a. is a fairly recent approach to provide higher data transmission rates across traditional voice circuits in the local loop
b. combines analog transmission and frequency division multiplexing
c. involves the use of a customer premises equipment (CPE)
d. uses a combination of amplitude and phase modulation
e. all of the above


Answer: all of the above

Inverse multiplexing means:

Inverse multiplexing means: 

a. combining several low speed circuits to enable them to be transmitted across one high speed circuit
b. multiplexing from the terminal to the host, rather than from the host to the terminal
c. combining high speed circuits to enable them to be transmitted across one low speed circuit
d. inverting the frequencies used for transmission across a low speed circuit for switching to a digital circuit
e. multiplexing to a codec, rather than to a modem


Answer: combining several low speed circuits to enable them to be transmitted across one high speed circuit

Statistical time division multiplexers differ from time division multiplexers because they:

Statistical time division multiplexers differ from time division multiplexers because they: 

a. can cause time delays when all devices are being used for data transmission at the same time
b. take idle time of terminals into account to increase circuit throughput
c. use a complicated statistical formula to allocate time slots
d. all of the above
e. none of the above



Answer: all of the above

Which of the following types of multiplexing is least efficient for data transmission?

Which of the following types of multiplexing is least efficient for data transmission? 

a. frequency division multiplexing
b. statistical time division multiplexing
c. statistical frequency division multiplexing
d. time division multiplexing
e. wave division multiplexing



Answer: frequency division multiplexing

_____ separate channels to reduce interference between channels in frequency division multiplexing.

_____ separate channels to reduce interference between channels in frequency division multiplexing.

a. Channel blockers
b. Statistical dividers
c. Attenuators
d. Guardbands
e. Adaptive differential processors



Answer: guardbands

Frequency division multiplexing:

Frequency division multiplexing: 

a. operates by statistically time slicing the signal
b. operates by dividing the signal into different frequencies
c. uses a codec that divides signals into different channels
d. operates by time slicing the signal
e. operates by light dividing the signal


Answer: operates by dividing the signal into different frequencies

The type of multiplexer that divides the circuit horizontally into different light frequencies that are transmitted simultaneously across many channels is

The type of multiplexer that divides the circuit horizontally into different light frequencies that are transmitted simultaneously across many channels is 

a. wave division multiplexer
b. time division multiplexer
c. statistical time division multiplexer
d. frequency division multiplexer
e. statistical frequency division multiplexer


Answer: wave division multiplexer

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

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

a. transponder
b. multiplexer
c. inverse multiplexer
d. codec
e. intelligent terminal



Answer: multiplexer

A 56K modem that uses the V.90 standard:

A 56K modem that uses the V.90 standard:

a. never has problems with noise on the telephone line
b. can recognize an 8-bit digital symbol 8000 times per second
c. transmits 56,000 different symbol changes per second at all times
d. can be used at full capacity on all North American telephone lines
e. currently has 56K transmission rates in both upstream and downstream channels


Answer: can recognize a 8-bit digital symbol 8000 times per second

When converting analog voice data to digital signals, Pulse Code Modulation samples the incoming voice signal _______ times per second.

When converting analog voice data to digital signals, Pulse Code Modulation samples the incoming voice signal _______ times per second.

a. 8,000
b. 8
c. 18,000
d. 64
e. 256



Answer: 8,000

__________ 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.

__________ 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.

a. quantizing error
b. handshaking phase
c. modulating frequency
d. POTS anomaly
e. amplitude Trellis effect



Answer: quantizing error

Codec refers to:

Codec refers to:

a. codependent decreasing compression
b. co- Digital Equipment Corporation
c. Codd's laws for data relations
d. code/decode
e. continuous operational digital energy communication



Answer: code/decode

When V.34 modems initially connect, they must go through a ____________ sequence to test the circuit and determine the optimum combination of symbol rate and modulation technique that will produce the highest throughput.

When V.34 modems initially connect, they must go through a ____________ sequence to test the circuit and determine the optimum combination of symbol rate and modulation technique that will produce the highest throughput.

a. frequency division
b. wave division
c. handshaking
d. Trellis-coded modulation
e. point of presence



Answer: handshaking

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

_____ 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


Answer: V.44

Which statement is false about modems?

Which statement is false about modems?

a. modems are usually used in pairs (2 at a time)
b. a receiving modem demodulates and a sending modem modulates
c. most modems support several modem standards so that they can communicate with a variety of modems
d. modems may operate at a lower speed that that for which they are rated, especially if they detect noise in the communication line
e. modems must always be internal to the computer


Answer: modems must always be internal to the computer

The acronym, Modem, stands for _________________.

The acronym, Modem, stands for _________________.

a. multiplexing/demultiplexing
b. more/demote
c. Mode-M technique
d. modulator/demodulator
e. Mod emulation technique


Answer: modulator/demodulator

Using TCM that sends 6 bits per each signal and a voice grade line with a bandwidth of 3000 Hz (assume: no noise on the line), the data capacity would be ___________ bits per second.

Using TCM that sends 6 bits per each signal and a voice grade line with a bandwidth of 3000 Hz (assume: no noise on the line), the data capacity would be ___________ bits per second. 

a. 56K
b. 6
c. 24,000
d. 500
e. 18,000



Answer: 18,000

Which of the following statements is true?

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
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


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

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

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



Answer: increase the range of frequencies available for a transmission