S305 Chapter 3
Fiber optic cable can only be used on LANs.
Answer: False
Fiber optic cable carries signals in traditional electrical form
Answer: False
A walkie-talkie is an example of half-duplex transmission.
Answer: True
Coding schemes are groups of bits that translate into the "alphabet" of any given system.
Answer: True
Computers produce digital data whose values are binary: 0 or 1.
Answer: True
Ethernet, a common LAN technology, uses Manchester encoding.
Answer: True
Of all the media available, fiber optic provides the highest transmission speeds.
Answer: True
The physical layer is a layer where two communicating nodes are directly connected.
Answer: True
____________ transmission is prone to interference from smoke, heavy rain and fog and requires line-of-sight. a. microwave b. radio c. infrared d. fiber optic e. led
Answer: C
A(n) __________ circuit is another name for a multipoint configuration. a. analog b. dedicated c. point-to-point d. shared e. simplex
Answer: D
The acronym, Modem, stands for _________________. a. multiplexing/demultiplexing b. more/demote c. Mode-M technique d. modulator/demodulator e. Mod emulation technique
Answer: 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
Answer: D
Coaxial cable costs less and offers less shielding to electrical interference than twisted pair cable.
Answer: False
Digital transmission occurs when the signal sent over the transmission media constantly varies among an infinite number of states.
Answer: False
Frequency division multiplexing divides the circuit into a set of different time slots.
Answer: False
Frequency modulation refers to the changing of the height of the sound wave.
Answer: False
Guided media refers to the type of media in which the message is broadcast through the air.
Answer: False
In a multipoint circuit configuration, each computer has a dedicated circuit between itself and each of the other computers in the network
Answer: False
In simplex transmission, the data flows in both directions at the same time
Answer: False
Infrared transmission uses high-frequency light waves to carry data through the air on a direct line-of-sight path between two points.
Answer: False
Multimode fiber is capable of longer transmission distances than single mode fiber.
Answer: False
Multiplexing increases the cost of provisioning network circuits.
Answer: False
Nonreturn to zero is a type of unipolar signaling
Answer: False
Radio, infrared, microwave and satellite are all examples of guided media.
Answer: False
Serial mode transmission is much faster than parallel mode transmission.
Answer: False
Wavelength division multiplexing can only used with copper cables.
Answer: False
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.
Answer: False
With nonreturn to zero signaling, the voltage alternates between zero and a positive or negative voltage.
Answer: False
Digital transmission produces more errors than analog transmission.
Answer: False.
Amplitude, frequency and phase are all characteristics of a sound wave.
Answer: True
Frequency is the number of cycles per second and is expressed in Hertz.
Answer: True
In full-duplex transmission, two stations can send and receive simultaneously.
Answer: True
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.
Answer: True
Radio data transmission requires that each device has a radio receiver/transmitter and uses a specific frequency.
Answer: True
Statistical time division multiplexing does not require the capacity of the circuit to be equal to the sum of the combined circuits.
Answer: True
The medium is the physical matter or substance that carries the voice or data transmission.
Answer: True
The predominant method of transferring information internally in a computer is via parallel mode.
Answer: True
Time division multiplexing is more efficient that frequency division multiplexing because the guardbands used in the frequency division multiplexing or not needed.
Answer: True
ASCII is the least popular code for data communications.
Answer: False
Which of the following statements is true? A. Bandwidth is constant across any wire, therefore distance is not relevant to its capacity B. The longer the distance of a telephone wire between sender and recipient, the lower the bandwidth across that wire C. The longer the distance of a telephone wire between sender and recipient, the higher the bandwidth across that wire D. The shorter the distance of a telephone wire between sender and recipient, the lower the bandwidth across that wire
Answer Key: A
Digital Subscriber Line (DSL): 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. uses a combination of amplitude and phase modulation D. all of the above E. none of the above
Answer Key: D
The _____________ of a circuit determines a circuit's capacity. A. amplitude B. frequency C. phase D. bandwidth
Answer Key: D
Microwave transmissions require a line of sight between any two points
Answer Key: True
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
Answer: A
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: A
The type of multiplexer that divides the circuit horizontally into different light frequencies that are transmitted simultaneously across many channels is a: a. wavelength division multiplexer b. time division multiplexer c. statistical time division multiplexer d. frequency division multiplexer e. statistical frequency division multiplexer
Answer: 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
Answer: A
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
Answer: A
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.
Answer: A
____________ is one of the most commonly used coding schemes used in data transmission. a. ASCII b. ISDN c. MAU d. ATM e. FDM
Answer: A
_____________ 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
Answer: A
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: B
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: B
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
Answer: B
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
Answer: B
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: B
__________ is a line-of-sight type of wireless media. a. coaxial cable b. microwave c. radio d. twisted pair e. fiber optic
Answer: 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
Answer: C
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
Answer: C
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
Answer: C
The earliest type of fiber optic systems were: a. Graded index multimode b. Attenuated c. Multimode d. Single mode e. Step mode
Answer: C
The height of a sound wave is called its: a. frequency b. phase c. amplitude d. bandwidth e. furlong
Answer: C
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
Answer: C
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
Answer: C
_________ is the basic physical layout of the circuit. a. point-to-point configuration b. configuration c. circuit configuration d. circuit design e. circuit plan
Answer: C
___________ 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
Answer: C
____________ 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
Answer: C
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.
Answer: 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
Answer: D
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: D
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
Answer: D
____________ refers to the transmission characteristics of the circuit. a. handshaking b. virtual circuit c. bonding d. logical circuit e. physical circuit
Answer: D
Another term for the weakening of a signal over distance is: a. turnaround time b. propagation delay c. dispersion d. insulation e. attenuation
Answer: E
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
Answer: E
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
Answer: E
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
Answer: E
Which of the following media is the least secure? a. coaxial cable b. unshielded twisted pair c. shielded twisted pair d. fiber optic cable e. infrared
Answer: E
___________ 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
Answer: E
A physical circuit refers to the transmission characteristics of the connection.
Answer: False
Baud rate is the number of bits transmitted per second.
Answer: False
