60 Questions
What is the data rate of the T1 carrier?
544 Mbps
In digital transmission, how are phase distortion problems corrected?
By applying conditioning
What does the public switched telephone network digitize your voice using?
Analog-to-digital circuit
What is the continuous data rate produced by the 8 kHz sampling rate in the phone company's digitization process?
64 Kbps
What is used to deal with the problem of echo in long analog lines?
An echo suppressor
What begins the process of breaking up a digital data stream into packets or fragments of packets in packet switching?
Packet assembly/disassembly device
Which technology commands the lion’s share of technical attention according to the text?
Voice over IP
What is the process where a carrier's waveform is modified to contain data?
Modulation
Which characteristic of a carrier can be modified in amplitude modulation?
Amplitude
What type of modulation varies the carrier's frequency based on the amplitude of the modulating signal?
Frequency Modulation
Which type of wave can be modeled using its fundamental frequency and odd harmonics?
Square wave
What do inductors and capacitors represent in wireline data transmission?
Lumped schematic symbols
What kind of data encoding increases the data rate without requiring higher line signaling rates?
Data Compression
What process originated in the 1960s for long-distance data transmission?
Serial modems
What is used as carriers in modulation due to their inability to be integrated or differentiated mathematically?
Sine waves
What is the term for the division of wireline modems into Bell1 and ITU2 classes?
Categorization
Which modern modem uses di-bit-encoded quaternary phase shift keying for noise advantages?
Bell 212 modem
What do modem manufacturers offer in addition to data compression?
Error Detection/Correction Schemes
What does the chapter discuss about Wide Area Networks (WANs)?
The ownership of the communication media and infrastructure
Why were wireline modems initially used even though they were slow?
They were the only available modem technology at that time
In the context of WANs, what does the Physical layer of the ISO OSI model provide?
Mechanical and electrical means to establish physical connections
What is the purpose of modulation in electrical communications?
To transmit data by modifying a carrier signal
Why do LANs not normally run over a WAN?
WANs are typically used for larger geographical areas
What is the primary reason for using one of the wide area technologies described in the chapter?
To facilitate communication between LANs and external networks
What is the main characteristic that has remained unchanged in WAN media despite changing business drivers and purposes?
Impedance of twisted copper line pairs
What is the function of demodulation in electrical communications?
To remove the intelligence from the carrier signal
What is the typical speed for most fractional T1 lines?
768 Kbps
Which WAN technology is described as a fiber optic token-passing ring?
Fiber Distributed Data Interface
What technology is primarily a fiber optic transmission system and uses small transmission packets called cells?
Asynchronous Transfer Mode
Which technology uses the same copper pairs that bring voicegrade wireline to residences or businesses?
Digital Subscriber Line
What is the data rate originally scheduled for Asynchronous Transfer Mode (ATM)?
155 Mbps
Which technology is described as suitable for highbandwidth applications like multisite video conferencing?
Asynchronous Transfer Mode
What are the typical speeds for the operation of MANs?
155 Mbps
What does FDDI consist of?
Dual counter-rotating fiber ring and token-passing technology
What is the most common speed for Fast Ethernet?
100 Mbps
What WAN technology can be configured in differing topologies and is often used as a dual counter-rotating ring topology?
Synchronous Optical Network
Which technology is considered a broadband technology allowing concurrent telephone, video, and data services on the line?
Digital Subscriber Line
What are the various speeds at which ATM technology can operate?
25 Mbps through 2.3 Gbps
What is the main objective of ISDN?
To offer voice, data, and video integrated into one service
What is the main difference between connection-oriented and connectionless service?
Connection-oriented service stores packets at one point while they wait for an available path
What is the purpose of the D channel in ISDN?
To provide control signals and meet other low-speed signaling requirements
What technology is frame relay a connectionless version of?
X.25
What type of data service does DDS (Dataphone Digital Service) offer?
Digital transmission with the need for modems
What is the main purpose of a T3 carrier?
To consist of 28 T1 lines
What is the technique used by the PAD in the packet-switching scheme provided by X.25?
Creating and adding headers to each of the small packets
What type of traffic did ISDN achieve popularity for in the United States?
'Relatively fast Internet access'
What does Frame Relay DDS provide?
'56 Kbps with no CIR'
What is the maximum speed of Frame Relay?
As high as you have the pocket money to afford
What does a T1 carrier multiplex onto one line?
Outputs of 24 DS0 channels
What was the original intention of ISDN's B channels?
To carry digitized voice or data on either channel
What is the purpose of the Microcom Networking Protocol (MNP)?
To negotiate and establish data transmission parameters
Which aspect of the V.42 standard contributes to data compression?
Using code lists to represent strings of characters
What is the primary function of modems according to the text?
Frequency translation
What was the basis for the discrete multi-tone process used in DSL lines?
A variety of techniques developed for high-speed data transmission over a 3 KHz wireline
Which type of network does the Internet represent?
Wide Area Network (WAN)
What is the function of MNPs 3 through 5 according to the text?
Addressing a range of parameters for data transmission
What is the proprietary domain status of MNPs 6 through 10?
They are still in the proprietary domain
What is the role of modems in operating over a typical telephone wireline?
Performing frequency translation
Which modern modem feature is concerned with packetizing data?
(MNP) packetizing data
(V.42) employs which frame and technique to perform data compression?
(LAP-M) frame and using code lists for data compression
Study Notes
- The text discusses various modulation techniques used in data communications.
- Wireline data transmission is often perceived as instantaneous due to short lengths of wire and effects like turning on car headlights.
- However, long lengths of wire introduce inductance and capacitance, affecting the transmitted signal.
- Inductors and capacitors are represented by lumped schematic symbols.
- A square wave can be modeled using its fundamental frequency and odd harmonics.
- Sine waves are used as carriers due to their inability to be integrated or differentiated mathematically.
- Modulation is the process where a carrier's waveform is modified to contain data.
- Amplitude, frequency, and phase are the three characteristics of a carrier that can be modified.
- Amplitude modulation changes the carrier's amplitude according to the data signal.
- Frequency modulation varies the carrier's frequency based on the amplitude of the modulating signal.
- Phase modulation shifts the carrier's phase according to the modulating signal's amplitude.
- Data can be encoded to increase the data rate without requiring higher line signaling rates.
- Serial modems originated in the 1960s for long-distance data transmission.
- Wireline modems are divided into Bell1 and ITU2 classes.
- Modern modems use Link Access Protocol and can be synchronous or asynchronous.
- Bell 212 modem uses di-bit-encoded quaternary phase shift keying for noise advantages.
- Modem manufacturers offer different data compression and error detection/correction schemes.
- Through repetitive data encoding, data compression increases throughput.
Explore the various modulation techniques used in wireline data transmission, including amplitude, frequency, and phase modulation. Learn how data is encoded to increase data rates and how modern modems utilize different schemes for data compression and error detection/correction.
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