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66 Cards in this Set
- Front
- Back
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__________ transmission sends bits one at a time over a single transmission line or electricl circuit.
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Serial
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During half-duplex transmission, sender and receiver switch roles after a(n) __________ message is transmitted.
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line turnaround
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__________ encodes data by varying the distance between wave peaks in an analog signal.
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Frequency modulation or FM
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A(n) __________ converts a digital signal to an analog signal so that digital data can be transmitted over analog phone lines.
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modem
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Serial transmission standards, including __________ and __________, are replacing parallel transmission standards for connecting secondary storage devices and controllers.
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Serial Advanced Technology Attachment (SATA) and Serial Attached SCSI (SAS)
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The __________ of a sine wave is measured in hertz.
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frequency
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Most local phone service uses __________ switching to route messages from a wired home phone to the local phone-switching center.
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circuit
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Most networks use __________ switching to send messages from sender to receiver.
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packet
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In __________, a bit is added to each character or byte, and the bit value is determined by counting the number of 1 bits.
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parity checking
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A(n) __________ signal is a discrete signal that can encode only two possible values.
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binary
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A(n) __________ wave transports encoded data through a transmission medium.
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carrier
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With parity checking, sender and receiver must agree whether error detection is based on __________ or __________.
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even parity, odd parity
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A channel’s __________ describes the mathematical relationship between noise power and signal power.
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S/N ratio
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__________ is any change in a signal characteristic caused by components of the communication channel.
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Distortion
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For any error-detection method, a decrease in ___________ is accompanied by an increase in ______________ error.
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Type I error, Type II error
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__________ can’t affect optical signals but can affect electrical or RF signals.
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Electromagnetic interference or EMI
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A communication channel using electrical signals must have at least two wires—a(n) __________ and a(n) __________—to form a complete electrical circuit.
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signal wire, return wire
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__________ measures a channel’s theoretical capacity. __________ measures the actual capacity of a channel when a specific communication protocol is used.
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Raw data transfer rate, Effective data transfer rate
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Multiple messages can be transmitted on a single transmission line or circuit by __________ multiplexing or __________ multiplexing.
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frequency-division, time-division
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A(n) __________ signal can encode an infinite number of possible numeric values.
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analog
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__________ is a measure of peak signal strength.
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Amplitude
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In asynchronous transmission, at least one __________ is added to the beginning of each message.
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start bit
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The term __________ describes encoding data as variations in one or more physical parameters of a signal.
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modulation
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In __________ transmission, blocks or characters arrive at unpredictable times, and no signal is transmitted during idle periods.
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asynchronous
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A medium’s __________ is the difference between the highest and lowest frequencies that can be transmitted.
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bandwidth
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__________ mode implements two-way transmission with two separate communication channels; __________ mode implements two-way transmission with only one communication channel.
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Full-duplex, half-duplex
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__________ encodes data by varying the magnitude of wave peaks in an analog signal.
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Amplitude modulation or AM
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__________ transmission uses multiple lines to send multiple bits simultaneously.
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Parallel
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A(n) __________ extends a signal’s range by retransmitting the signal without any noise or distortion from earlier transmission stages.
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repeater
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__________ generates a(n) __________ consisting of a single parity bit for each bit position in the group of characters or bytes.
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Block (or vertical redundancy) checking, block check character or BCC
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In __________ transmission, signals are transmitted continuously, even when there’s no data to send, to ensure clock synchronization.
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synchronous
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__________ uses more than two signal characteristic levels to encode multiple bits in a single signal.
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Multilevel coding
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__________ encodes bit values with rapid pulses of electrical or optical power.
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On-off keying
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__________ is noise added to the signal from EMI generated by adjacent transmission lines in a parallel communication channel.
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Crosstalk
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Frequency-division multiplexing of optical channels is sometimes called __________.
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wavelength-division multiplexing
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The length of a parallel communication channel is limited by __________, which can cause bits to arrive at slightly different times.
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skew
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A receiver informs a sender that data was received correctly by sending a(n) __________ message. It informs the sender of a transmission or reception error by sending a(n) __________ message.
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ACK, NAK
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__________ is loss of signal strength as it travels through a transmission medium.
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Attenuation
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Messages transmitted by time-division multiplexing are divided into __________ before physical transmission.
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packets
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__________ cable is an improved version of Category 5 cable that transmits data at high speeds more reliably.
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Category 6
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Wireless LANs following the IEEE ____________, ____________, and ____________ standards transmit in the 2.4 GHz band.
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802.11b, 802.11g, 802.11n
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The __________ standards define many aspects of physical networks.
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IEEE 802
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The OSI __________ layer establishes and manages connections between clients and servers.
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Session
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The __________ protocol is an updated version with larger addresses and improved support for multicasting and multimedia data.
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IPv6
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The __________ topology is most common in wired networks, and the ___________ topology is most common in wireless networks.
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star, bus
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The OSI __________ layer forwards messages to their correct destinations.
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Network
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A __________ is the combination of an IP address and a port number.
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socket
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The OSI __________ layer refers to communication protocols used by programs, such as Web browsers, that generate requests for network services.
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Application
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A network using a physical __________ topology connects all end nodes to a central node.
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star
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A physical connection between two different networks is implemented by using a(n) __________, __________, or __________.
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switch, router, wireless access point (or wireless AP)
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A receiver can’t detect loss of datagrams if a(n) __________ protocol is used.
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connectionless
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In the TCP/IP model, a(n) __________ is the basic data transfer unit.
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datagram
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The original __________ standard transmits at 10 Mbps over twisted-pair cabling. Current standard versions support 1 and 10 Gbps transmission over twisted-pair and fiber-optic cable.
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Ethernet
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The __________ defines conceptual software and hardware layers for networks.
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OSI model
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The __________ MAC protocol is used in wireless networks to prevent most collisions.
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CSMA/CA
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When two messages are transmitted at the same time on a shared medium, a(n) __________ has occurred.
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collision
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With the __________ MAC protocol, collisions can occur, but they’re detected and corrected.
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CSMA/CD
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A(n) __________ protocol defines the rules governing a network node’s access to a transmission medium.
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Media Access Control or MAC
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An end node’s hardware interface to a network transmission medium is called a(n) __________.
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network interface card or NIC
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The __________ protocol is used with broadcast and multimedia applications when processing overhead needs are low and reliable delivery doesn’t need to be guaranteed.
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UDP
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The oldest and most widely used VoIP protocol suite is __________.
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H.323
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Roughly corresponds to the OSI Application and Presentation layers and includes many protocols, such as HTTP, SMTP, DNS, and DHCP. Supports applications such as e-mail programs and Web browsers.
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Application layer
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Roughly equivalent to the OSI Session and Transport layers and includes TCP and UDP. Provides reliable additional services beyond the Internet layer, including error detection and correction and guaranteed delivery of IP packets.
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Transport layer
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Roughly corresponds to the OSI Network layer. IP is the primary protocol, although other protocols, such as ICMP, ARP, and RARP, play a supporting role. Handles basic transport of messages without error detection or delivery guarantees.
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Internet layer
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Roughly equivalent to the OSI Data Link layer. This layer connects Internet protocols to underlying network protocols in the Physical layer and converts network addresses and packet formats as needed.
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Network Interface layer
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Roughly equivalent to the OSI Physical layer. This layer contains physical network protocols, such as Ethernet and ATM, and physically transports messages from sender to receiver.
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Physical layer
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