Shared Flashcard Set

Details

Ch3 Transmission Basics and Networking Media
N/A
159
Computer Networking
Graduate
05/31/2013

Additional Computer Networking Flashcards

 


 

Cards

Term
Your campuswide WAN is experiencing slow Internet response times. When you call your Internet service provider to ask if they can troubleshoot the problem from their end, they warn you that their responsibilities end at the demarc. What do they mean?
A. They will not diagnose problems beyond your organizations's IDF.
B. They will not diagnose problems beyond your organization's telco rooms.
C. they will not diagnose problems beyond your organization's MDF.
D. They will not diagnose problems beyond your organization's entrance facilities.
Definition
D. They will not diagnose problems beyond your organization's entrance facilities.
Term
An Ethernet cable terminated according to the TIA/EIA-568-A standard on one end and the TIA/EIA-568-B standard on the other end is an example of:
A. patch cable
B. straight-through cable
C. coaxial cable
D. crossover cable
Definition
D. crossover cable
Term
The distance between corresponding points on a wave's cycle is called its _____.
A. amplitude
B. frequency
C. phase
D. wavelength
Definition
D. wavelength
Term
How many wire pairs can a single 110 block terminate?
A. 200
B. It depends on the type of 110 block.
C. 110
D. 55
Definition
B. It depends on the type of 110 block.
Term
Every user at one location on your company's WAN is unable to reach the Internet. Your colleague on the network management team suspects a critical router is unable to connect to the network. Because you're in the building affected by the outage, she asks you to troubleshoot the router. You confirm that the router is not responding to any requests over the network. Which of the following do you use to connect directly from your laptop to the router to diagnose it?
A. An RG-58 cable
B. A serial cable
C. An RG-6 cable
D. An SMF cable
Definition
B. A serial cable
Term
The byte 00001110 means _____ on a digital network.
A. 30
B. 6
C. 14
D. 3
Definition
C. 14
Term
Many network problems can be traced to poor cable ____ techniques.
A. manufacturing
B. engineering
C. installation
D. planning
Definition
C. installation
Term
The more twists per foot in a pair of wires, the more resistant the pair will be to _____.
A. throughput
B. cross talk
C. latency
D. attenuation
Definition
B. cross talk
Term
Which of the following decimal numbers corresponds to the binary number 00001001?
A. 7
B. 5
C. 9
D. 3
Definition
C. 9
Term
Which of the following network transmission media offers the highest potential throughput over the longest distances?
A. UTP
B. ST
C. MMF
D. SMF
Definition
D. SMF
Term
What is the maximum distance specified in the structured cabling standard for a horizontal wiring subsystem?
A. 90 m
B. 200 m
C. 100 m
D. 10 m
Definition
C. 100 m
Term
One of the most common transmission flaws affecting data signal is _____.
A. noise
B. attenuation
C. throughput
D. latency
Definition
A. noise
Term
In wavelength division multiplexing, two modulated signals are guaranteed to differ in what characteristic?
A. Amplitude
B. Phase
C. Color
D. Throughput
Definition
C. Color
Term
_____ describes wiring that connects workstations to the closest telecommunications closet.
A. Backbone wiring
B. Horizontal wiring
C. Work area
D. Simple wiring
Definition
B. Horizontal wiring
Term
The most significant factor in choosing a transmission method is _____.
A. attenuation
B. latency
C. noise
D. throughput
Definition
D. throughput
Term
Which term identifies a room containing connectivity for groups of workstations in its area?
A. telecommunications closet
B. MDF (main distribution frame)
C. entrance facilities
D. work area
Definition
A. telecommunications closet
Term
Which of the following cabling types is used with BNC connections?
A. unshielded twisted pair (UTP)
B. fiber-optic
C. coaxial
D. twisted pair
Definition
C. coaxial
Term
The points where circuits interconnect with other circuits is known as _____.
A. IDF (intermediate distribution frame)
B. cross-connect facilities
C. telecommunications closet
D. entrance facilities
Definition
B. cross-connect facilities
Term
Which of the following statements are true?
A. modems can only be used for dial-up connections
B. modem converts analog signal to digital signal
C. modem converts digital signal to analog signal
D. modems can only be used in PSTN networks
E. modems can only be used to transmit data over telephone lines
Definition
B. modem converts analog signal to digital signal
C. modem converts digital signal to analog signal
Term
What part of a cable protects it against environmental damage?
A. cladding
B. plenum
C. braiding
D. sheath
Definition
D. sheath
Term
_____ is a technology used with fiber-optic cable, which enables one fiber-optic connection to carry multiple light signals simultaneously.
A. FDM (frequency division multiplexing)
B. statistical multiplexing
C. TDM (time division multiplexing
D. WDM (wavelength division multiplexing)
Definition
D. WDM (wavelength division multiplexing)
Term
You are helping to install a cable broadband system in your friend's home. She wants to bring the signal from where the service provider's cable enters the house to a room on another floor, which means you have to attach a new cable to the existing one. What type of cable should this be?
A. RG-58
B. RG-6
C. RG-8
D. RG-59
Definition
B. RG-6
Term
Which of the following is not a source of EMI?
A. Power line
B. Fluorescent lights
C. Megaphone
D. Microwave oven
Definition
C. Megaphone
Term
What is different about the method used to boost a digital signal's strength, compared with the method of boosting an analog signal's strength?
A. A digital signal requires an amplifier, which introduces noise into the signal, and an analog signal requires a repeater, which retransmits the signal in its original form.
B. A digital signal requires a repeater, which increases the strength of both the signal and the noise it has accumulated, and an analog signal requires an amplifier, which retransmits the signal in its original form.
C. A digital signal requires an amplifier, which increases the strength of both the noise and the signal, and an analog signal requires a repeater, which retransmits the signal in its original form.
D. A digital signal requires a repeater, which retransmits the signal in its original form, and an analog signal requires an amplifier, which increases the strength of both the signal and the noise it has accumulated.
Definition
D. A digital signal requires a repeater, which retransmits the signal in its original form, and an analog signal requires an amplifier, which increases the strength of both the signal and the noise it has accumulated.
Term
The serial interface on the back of the connectivity device is often labeled "_____".
A. Connector
B. Board
C. Port
D. Console
Definition
D. Console
Term
With everything else being equal, a network using which of the following UTP types will suffer the most cross talk?
A. Cat 5
B. Cat 6a
C. Cat 3
D. Cat 7
Definition
C. Cat 3
Term
Fiber-optic cable networks can span much longer distances than copper-based networks before requiring repeaters because:
A. their signals do not suffer degradation no matter how small the cable's bend radius.
B. their signals never require amplification.
C. they are resistant to noise such as EMI.
D. they use wavelength division multiplexing.
Definition
C. they are resistant to noise such as EMI.
Term
Which of the following is the most important factor when installing cabling in plenum spaces?
A. fire safety
B. EMI resistance
C. RFI resistance
D. connection speed
Definition
A. fire safety
Term
A wave with which of the following frequencies would have the longest wavelength?
A. 10 MHz
B. 100 MHz
C. 1 GHz
D. 100 GHz
Definition
A. 10 MHz
Term
Ethernet relies on which of the following transmission types?
A. Simplex
B. Half-simplex
C. Half-duplex
D. Full-duplex
Definition
D. Full-duplex
Term
Which of the following can increase latency on a network?
A. An EMI source, such as fluorescent lighting
B. The use of full-duplex transmission
C. The use of multiple protocols
D. Adding 50 meters to the length of the network
Definition
D. Adding 50 meters to the length of the network
Term
In which of the following network links might you use MT-RJ connectors?
A. A coaxial connection between a cable modem and a server
B. A UTP connection between a workstation and a hub
C. A wireless connection between a handheld computer and a desktop computer
D. A fiber-optic connection between a server and router
Definition
D. A fiber-optic connection between a server and router
Term
What is the purpose of cladding in a fiber-optic cable?
A. It reflects the signal back to the core.
B. It protects the inner core from damage.
C. It shields the signal from EMI.
D. It concentrates the signal and helps keep it from fading.
Definition
A. It reflects the signal back to the core.
Term
Which of the following is a potential drawback to using fiber-optic cable for LANs?
A. It is expensive.
B. It cannot handle high-bandwidth transmissions.
C. It can carry transmissions using only TCP/IP.
D. It is not yet an accepted standard for high-speed networking.
Definition
A. It is expensive.
Term
In what part of a structured cabling system would you find users' desktop computers?
A. Telco room
B. MDF
C. IDF
D. Work area
Definition
D. Work area
Term
1 gigabit per second (Gbps)
Definition
1,000,000,000 bits per second
Term
1 kilobit per second (Kbps)
Definition
1000 bits per second
Term
1 megabit per second (Mbps)
Definition
1,000,000 bits per second
Term
1 terabit per second (Tbps)
Definition
1,000,000,000,000 bits per second
Term
100-pair wire
Definition
UTP supplied by a telecommunications carrier that contains 100 wire pairs
Term
110 block
Definition
Part of an organization's cross-connect facilities, a type of punch-down block designed to terminate Cat 5 or better twisted pair wires.
Term
25-pair wire
Definition
UTP supplied by a telecommunications carrier that contains 25 wire pairs.
Term
alien cross talk
Definition
EMI interference induced on one cable by signals traveling over a nearby cable.
Term
AM (amplitude modulation)
Definition
A modulation technique in which the amplitude of the carrier signal is modified by the application of a data signal.
Term
amplifier
Definition
A device that boosts, or strengthens, an analog signal.
Term
amplitude
Definition
A measure of a signal's strength.
Term
analog
Definition
A signal that uses variable voltage to create continuous waves, resulting in an inexact transmission.
Term
attenuation
Definition
The extent to which a signal has weakened after traveling a given distance.
Term
AWG (American Wire Gauge)
Definition
A standard rating that indicates the diameter of a wire, such as the conducting core of a coaxial cable.
Term
bandwidth
Definition
A measure of the difference between the highest and lowest frequencies that a medium can transmit.
Term
baseband
Definition
A form of transmission in which digital signals are sent through direct current pulses applied to a wire. This direct current requires exclusive use of the wire's capacity, so baseband systems can transmit only one signal, or one channel, at a time. Every device on a baseband system shares a single channel.
Term
bend radius
Definition
The radius of the maximum arc into which you can loop a cable before you will cause data transmission errors. Generally, a twisted pair cable's bend radius is equal to or greater than four times the diameter of the cable.
Term
binary
Definition
A system founded on using 1s and 0s to encode information.
Term
bit (binary digit)
Definition
A bit equals a single pulse in the digital encoding system. It may have only one of two values: 0 or 1.
Term
BNC (Bayonet Neill-Concelman, or British Naval Connector)
Definition
A standard for coaxial cable connectors named after its coupling method and its inventors.
Term
BNC connector
Definition
A coaxial cable connector type that uses a twist-and-lock (or bayonet) style of coupling. It may be used with several coaxial cable types, including RG-6 and RG-59.
Term
braiding
Definition
A braided metal shielding used to insulate some types of coaxial cable.
Term
broadband
Definition
A form of transmission in which signals are modulated as radio frequency analog pulses with different frequency ranges. Unlike baseband, broadband technology does not involve binary encoding. The use of multiple frequencies enables a broadband system to operate over several channels and, therefore, carry much more data than a baseband system.
Term
broadcast
Definition
A transmission that involves one transmitter and multiple, undefined receivers.
Term
byte
Definition
Eight bits of information. In a digital signaling system, broadly speaking, 1 byte carries one piece of information.
Term
cable plant
Definition
The hardware that constitutes the enterprise-wide cabling system.
Term
Cat
Definition
Abbreviation for the word "category" when describing a type of twisted pair cable. For example, Category 5 unshielded twisted pair cable may also be called Cat 5.
Term
Cat 3
Definition
A form of UTP that contains four wire pairs and can carry up to 10 Mbps, with a possible bandwidth of 16 MHz. Cat 3 was used for 10-Mbps Ethernet or 4-Mbps token ring networks.
Term
Cat 5
Definition
A form of UTP that contains four wire pairs and supports up to 100-Mbps throughput and a 100-MHz signal rate.
Term
Cat 5e (Enhanced)
Definition
A higher-grade version of Cat 5 wiring that contains high-quality copper, offers a high twist ratio, and uses advanced methods for reducing cross talk. Enhanced Cat 5 can support a signaling rate of up to 350 MHz, more than triple the capability of regular Cat 5.
Term
Cat 6
Definition
A twisted pair cable that contains four wire pairs, each wrapped in foil insulation. Additional foil insulation covers the bundle of wire pairs, and a fire-resistant plastic sheath covers the second foil layer. The foil insulation provides excellent resistance to cross talk and enables Cat 6 to support a signaling rate of 250 MHz and at least six times the throughput support by regular Cat 5.
Term
Cat 6a (Augmented)
Definition
A higher-grade version of Cat 6 wiring that further reduces attenuation and cross talk and allows for potentially exceeding traditional network segment length limits. Cat 6a is capable of a 500-MHz signaling rate and can reliably transmit data at multi-gigabit per second rates.
Term
Cat 7
Definition
A twisted pair cable that contains multiple wire pairs, each separately shielded then surrounded by another layer of shielding within the jacket. Cat can support up to a 1-GHz signal rate. But because of its extra layers, it is less flexible than other forms of twisted pair wiring.
Term
channel
Definition
A distinct communication path between two or more nodes, much like a lane is a distinct transportation path on a freeway. Channels may be separated either logically (as in multiplexing) or physically (as when they are carried by separate wires).
Term
cladding
Definition
The glass or plastic shield around the core of a fiber-optic cable. Cladding reflects light back to the core in patterns that vary depending on the transmission mode. This reflection allows fiber to bend around corners without impairing the light-based signal.
Term
coaxial cable
Definition
A type of cable that consists of a central metal conducting core, which might be solid or stranded and is often made of copper, surrounded by an insulator, a braided metal shielding, called braiding, and an outer cover, called the sheath or jacket. Coaxial cable, called "coax" for short, was the foundation for Ethernet networks in the 1980s. Today is's used to connect cable Internet and cable TV systems.
Term
conduit
Definition
The pipeline used to contain and protect cabling. Conduit is usually made from metal.
Term
connectors
Definition
The pieces of hardware that connect the wire to the network device, be it a file server, workstation, switch, or printer.
Term
core
Definition
The central component of a cable designed to carry a signal. The core of a fiber-optic cable, for example, consists of one or several glass or plastic fibers. The core of a coaxial copper cable consists of one large or several small strands of copper.
Term
crossover cable
Definition
A twisted pair patch cable in which the termination locations of the transmit and receive wires on one end of the cable are reversed.
Term
cross talk
Definition
A type of interference caused by signals traveling on nearby wire pairs infringing on another pair's signal.
Term
DB-9 connector
Definition
A type of connector with nine pins that's commonly used in serial communication that conforms to the RS-232 standard.
Term
DB-25 connector
Definition
A type of connector with 25 pins that's commonly used in serial communication that conforms to the RS-232 standard.
Term
demarcation point (demarc)
Definition
The point of division between a telecommunications service carrier's network and a building's internal network.
Term
demultiplexer (demux)
Definition
A device that separates multiplexed signals once they are received and regenerates them in their original form.
Term
digital
Definition
As opposed to analog signals, digital signals are composed of pulses that can have a value of only 1 or 0.
Term
DWDM (dense wavelength division multiplexing)
Definition
A multiplexing technique used over single-mode or multimode fiber-optic cable in which each signal is assigned a different wavelength for its carrier wave. In DWDM, little space exists between carrier waves in order to achieve extraordinary high capacity.
Term
EMI (electromagnetic interference)
Definition
A type of interference that may be caused by motors, power lines, televisions, copiers, fluorescent lights, or other sources of electrical activity.
Term
entrance facilities
Definition
The facilities necessary for a service provider (whether it is a local phone company, Internet service provider, or long-distance carrier) to connect with another organization's LAN or WAN.
Term
FDM (frequency division multiplexing)
Definition
A type of multiplexing that assigns a unique frequency band to each communications subchannel. Signals are modulated with different carrier frequencies, then multiplexed to simultaneously travel over a single channel.
Term
ferrule
Definition
A short tube within a fiber-optic cable connector that encircles the fiber strand and keeps it properly aligned.
Term
fiber-optic cable
Definition
A form of cable that contains one or several glass or plastic fibers in its core. Data is transmitted via pulsing light sent from a laser or light-emitting diode (LED) through the central fiber (or fibers). Fiber-optic cables offer significantly higher throughput than copper-based cables. They may be single-mode or multimode and typically use wave-division multiplexing to carry multiple signals.
Term
FM (frequency modulation)
Definition
A method of data modulation in which the frequency of the carrier signal is modified by the application of the data signal.
Term
frequency
Definition
The number of times that a signal's amplitude changes over a fixed period of time, expressed in cycles per second, or hertz (Hz).
Term
F-Type connector
Definition
A connector used to terminate coaxial cable used for transmitting television and broadband cable signals.
Term
full-duplex
Definition
A type of transmission in which signals may travel in both directions over a medium simultaneously. May also be called, simply, "duplex".
Term
half-duplex
Definition
A type of transmission in which signals may travel in both directions over a medium, but in only one direction at a time.
Term
hertz (Hz)
Definition
A measure of frequency equivalent to the number of amplitude cycles per second.
Term
IDF (intermediate distribution frame)
Definition
A junction point between the MDF and concentrations of fewer connections - for example, those that terminate in a telecommunications closet.
Term
impedence
Definition
The resistance that contributes to controlling an electrical signal. Impedance is measured in ohms.
Term
latency
Definition
The delay between the transmission of a signal and its receipt.
Term
LC (local connector)
Definition
A connector used with single-mode or multimode fiber-optic cable.
Term
MDF (main distribution frame)
Definition
Also known as the main cross-=connect, the first point of interconnection between an organization's LAN or WAN and a service provider's facility.
Term
media converter
Definition
A device that enables networks or segments using different media to interconnect and exchange signals.
Term
MMF (multimode fiber)
Definition
A type of fiber-optic cable that contains a core with a diameter between 50 and 100 microns, through which many pulses of light generated by a light-emitting diode (LED) travel at different angles.
Term
modem
Definition
A device that modulates digital signals into analog signals at the transmitting end for transmission over telephone lines, and demodulates analog signals into digital signals at the receiving end.
Term
modulation
Definition
A technique for formatting signals in which one property of a simple carrier wave is modified by the additions of a data signal during transmission.
Term
MT-RJ (mechanical transfer registered jack)
Definition
A connector used with single-mode or multimode fiber-optic cable.
Term
multiplexer
Definition
A device that separates a medium into multiple channels and issues signals to each of those subchannnels.
Term
multiplexing
Definition
A form of transmission that allows multiple signals to travel simultaneously over one medium.
Term
NEXT (near end cross talk)
Definition
Cross talk, or the impingement of the signal carried by one wire onto a nearby wire, that occurs between wire pairs near the source of a signal.
Term
noise
Definition
The unwanted signals, or interference, from sources near network cabling, such as electrical motors, power lines, and radar.
Term
nonbroadcast point-to-multipoint transmission
Definition
A communications arrangement in which a single transmitter issues signals to multiple, defined recipients.
Term
optical loss
Definition
The degradation of a light signal on a fiber-optic network.
Term
overhead
Definition
The nondata information that must accompany data for a signal to be properly routed and interpreted by the network.
Term
patch cable
Definition
A relatively short section (usually between 3 and 25 feet) of cabling with connectors on both ends.
Term
patch panel
Definition
A wall-mounted panel of data receptors into which cross-connect patch cables from the punch-down block are inserted.
Term
phase
Definition
A point or stage in a wave's progress over time.
Term
plenum
Definition
The area above the ceiling tile or below the subfloor in a building.
Term
point-to-multipoint
Definition
A communications arrangement in which one transmitter issues signals to multiple receivers. The receivers may be undefined, as in a broadcast transmission, or defined, as in a nonbroadcast transmission.
Term
point-to-point
Definition
A data transmission that involves one transmitter and one receiver.
Term
populated segment
Definition
A network segment that contains end nodes, such as workstations.
Term
punch-down block
Definition
A panel of data receptors into which twisted pair wire is inserted, or punched down, to complete a circuit.
Term
regeneration
Definition
The process of retransmitting a digital signal. Regeneration, unlike amplification, repeats the pure signal, with none of the noise it has accumulated.
Term
repeater
Definition
A device used to regenerate a signal.
Term
RFI (radio frequency interference)
Definition
A kind of interference that may be generated by broadcast signals from radio or TV antennas.
Term
RG-6
Definition
A type of coaxial cable with an impedance of 75 ohms and that contains an 18 AWG core conductor. RG-6 is used for television, satellite, and broadband cable connections.
Term
RG-8
Definition
A type of coaxial cable characterized by a 50-ohm impedance and a 10 AWG core. RG-8 provided the medium for the first Ethernet networks, which followed the now obsolete 10BASE-5 standard.
Term
RG-58
Definition
A type of coaxial cable characterized by a 50-ohm impedance and a 24 AWG core. RG-58 was a popular medium for Ethernet LANs in the 1980s, used for the now obsolete 10BASE-2 standard.
Term
RG-59
Definition
A type of coaxial cable characterized by a 75-ohm impedance and a 20 or 22 AWG core, usually made of braided copper. Less expensive but suffering greater attenuation than the more common RG-6 coax, RG-59 is used for relatively short connections.
Term
RJ-11 (registered jack 11)
Definition
The standard connector used with unshielded twisted pair cabling (usually Cat 3 or Level 1) to connect analog telephones.
Term
RJ-45 (registered jack 45)
Definition
The standard connector used with shielded twisted pair and unshielded twisted pair cabling.
Term
RS-232
Definition
A Physical layer standard for serial communications, as defined by EIA/TIA.
Term
RTT (round-trip time)
Definition
The length of time it takes for a packet to go from sender to receiver, then back from receiver to sender. RTT is usually measured in milliseconds.
Term
SC (subscriber connector or standard connector)
Definition
A connector used with single-mode or multimode fiber-optic cable.
Term
serial
Definition
A style of data transmission in which the pulses that represent bits follow one another along a single transmission line. In other words, they are issued sequentially, not simultaneously.
Term
serial cable
Definition
A cable, such as an RS-232 type, that permits serial data transmission.
Term
sheath
Definition
The outer cover, or jacket, of a cable.
Term
simplex
Definition
A type of transmission in which signals may travel in only one direction over a medium.
Term
SMF (single-mode fiber)
Definition
A type of fiber-optic cable with a narrow core that carries light pulses along a single path data from one end of the cable to the other end. Data can be transmitted faster and for longer distances on single-mode fiber than on multimode fiber. However, single-mode fiber is more expensive.
Term
ST (straight tip)
Definition
A connector used with single-mode or multimode fiber-optic cable.
Term
statistical multiplexing
Definition
A method of multiplexing in which each node on a network is assigned a separate time slot for transmission, based on the node's priority and need.
Term
STP (shielded twisted pair)
Definition
A type of cable containing twisted-wire pairs that are not only individually insulated, but also surrounded by a shielding made of a metallic substance such as foil.
Term
straight-through cable
Definition
A twisted pair patch cable in which the wire terminations in both connectors follow the same scheme.
Term
structured cabling
Definition
A method for uniform, enterprise-wide, multivendor cabling systems specified by the TIA/EIA 568 Commercial Building Wiring Standard. Structured cabling is based on a hierarchical design using a high-speed backbone.
Term
subchannel
Definition
One of many distinct communication paths established when a channel is multiplexed or modulated.
Term
TDM (time division multiplexing)
Definition
A method of multiplexing that assigns a time slot in the flow of communications to every node on the network and, in that time slot, carries data from that node.
Term
telecommunications closet
Definition
Also known as a "telco room," the space that contains connectivity for groups of workstations in a defined area, plus cross-connections to IDFs or, telecommunications closets per floor, but the TIA/EIA standard specified at least one per floor.
Term
Thicknet
Definition
An IEEE Physical layer standard for achieving a maximum of 10-Mbps throughput over coaxial copper cable. Thicknet is also known as 10Base-5. Its maximum segment length is 500 meters, and it relies on a bus topology.
Term
Thinnet
Definition
An IEEE Physical layer standard for achieving 10-Mbps throughput over coaxial copper cable. Thinnet is also known as 10Base-2. Its maximum segment length is 185 meters, and it relies on a bus topology.
Term
throughput
Definition
The amount of data that a medium can transmit during a given period of time. Throughput is usually measured in megabits (1,000,000,000 bits) per second, or Mbps. The physical nature of every transmission media determines its potential throughput.
Term
transceiver
Definition
A device that transmits and receives signals.
Term
transmission
Definition
In networking, the application of data signals to a medium or the progress of data signals over a medium from one point to another.
Term
Transmit
Definition
To issue signals to the network medium.
Term
twist ratio
Definition
The number of twists per meter or foot in a twisted pair cable.
Term
twisted pair
Definition
A type of cable similar to telephone wiring that consists of color-coded pairs of insulated copper wires, each with a diameter of 0.4 to 0.8 mm, twisted around each other and encased in plastic coating.
Term
unpopulated segment
Definition
A network segment that does not contain end nodes, such as workstations. Unpopulated segments are also called link segments.
Term
UTP (unshielded twisted pair)
Definition
A type of cabling that consists of one or more insulated wire pairs encased in a plastic sheath. As its name implies, UTP does not contain additional shielding for the twisted pairs. As a result, UTP is both less expensive and less resistant to noise than STP.
Term
vertical cross-connect
Definition
Part of a network's backbone that supplies connectivity between a buildings's floors. For example, vertical cross-connects might connect an MDF and an IDF or IDFs and telecommunications closets within a building.
Term
volt
Definition
The measurement used to describe the degree of pressure an electrical current exerts on a conductor.
Term
voltage
Definition
The pressure (sometimes informally referred to as the strength) of an electrical current.
Term
wavelength
Definition
The distance between corresponding points on a wave's cycle. Wavelength is inversely proportional to frequency.
Term
WDM (wavelength division multiplexing)
Definition
A multiplexing technique in which each signal on a fiber-optic cable is assigned a different wavelength, which equates to its own subchannel. Each wavelength is modulated with a data signal. In this manner, multiple signals can be simultaneously transmitted in the same direction over a length of fiber.
Term
zipcord cable
Definition
A relatively short fiber-optic cable in which two strands are arranged side by side in conjoined jackets, enabling full-duplex communication.
Supporting users have an ad free experience!