Analog signals
A signaling method in which electromagnetic waves very infinitely and continuously, and appear as a wavy line when graphed over time.
amplitude
A measure of a signal's strength at a given point in line.
frequency
The number of times that a wave's amplitude cycles from its starting point, through its highest amplitude and its lowest amplitude and back to its starting point over a fixed period of time, expressed in cycles per second, or hertz (Hz)
wavelength
The distance between corresponding point on a wave's cycle, expressed in meters or feet. Wavelength is inversely proportional to frequency.
phase
A point or stage in a wave's progress over time.
Digital signals
A signaling method composed of pulses of precise, positive voltages and zero voltages. Unlike analog signals, there is nothing infinte or continuous about a digital signal because it is ingerenly either on or off
modulation
A technique for formatting signals in which one property of a simple carrier wave is modified by the addition of a data signal during transmission.
FM (frequency modulation)
A method of data modulation in which the frequency of the carrier signal is modified by the application of the data signal.
AM (amplitude modulation)
A modulation technique in which the amplitude of the carrier signal is modified by the application of a data signal.
baseband
A form of transmission in which digital signals are sent through direct current pulses applied to a wire. This direct current require exclusive use of the wire's capacity, so baseband systems can transmit only one signal, or one channel, at a time. Every
broadband
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 o
multiplexing
A form of transmission that allows multiple signals to travel simultaneoulsy over one medium.
subchannels
One of many distinct communication paths established when a channel is multiplexed or modulated.
multiplexer (mux)
A device that separates a medium into multiple channels and issues signals to each of those subchannels.
demultiplexer (demux)
A device that separates multiplexed signals once they are received and regenerates then in their original form.
TDM (time division multiplexing)
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.
Statistical multiplexing
A method of multiplexing which each node on a network is assigned a separate time slot for traansmission, based on the node's priority and need.
FDM (frequency division multiplexing)
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.
WDM (wavelength division multiplexing)
A multiplexing technique in which each signal on a fiber-iptic 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 simultaneoulsy transmitt
DWDM (dense wavelength division multiplexing)
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 to achieve extraordinary high capacity.
CWDM (coarse wavelength division multiplexing)
A multiplexing technique used over single-mode or multimode fiber-optic cable in which each signal is assigned a different wavelength for it carrier wave. In CWDM, channels are spaced more widely apart than in DWDM to allow for the use of cheaper transcei
Throughput
The amount of data that a medium transmits during a given period of time. Throughput is usually measured in megabits (1,000,000 bits) per second, or Mbps.
bit rate
In digital transmissions, a measurement of throughput and bandwidth that is expressed as bits transmitted per sceond.
baud rate (Bd)
For analog transmissions, a measurement of througput and bandwidth that is detemined by symbols transmitted per second. A sysmbol is a viltage, frequency, pulse, or phase change in the analog transmission. Also called modulation rate or symbol rate.
ASCII
A character encoding system consisting of 128 characters.
Coaxial cable
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). Coa
braiding or shield
a braised metal shielding used to insulate some types of coaxial cable.
sheath
The outer cover, or jacket, of a cable
impedance
The resistance that contributes to controlling an electrical signal. Impedance is measured in ohms.
American Wire Gauge (AWG)
the size of the conducting core in a coaxial cable.
RG-6 (radio guide 6)
a type of coaxial cable with an impedance of 75 ohms and an 18 AWG core conductor. RG-6 is used for television, satellite, and broadband cable connections.
RG-8
a type of coaxial cable characterized by a 50-ohm impdance and a 10 AWG core conductor. RG-8 provided the medium for hte first Ethernet netorks and was called Thicknet.
RG-58
A type of coaxial cable characterized by a 50-ohm impedance and a 24 AWG core conductor. RG-58 was a popular medium for Ethernet LAANs in the 1980s and was call Thinnet, which is more flexible and easier to handle and install than Thicknet.
RG-59
A type of coaxial cable characterized by a 75-ohm umpedance and a 20 or 22 AWG core conductor, 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.
Thinnet
An outdated IEEE Physical layer standard for achieving 10-Mbps throughput over coaxial copper cable. Thinnet was also known as 10Base2. Its maximum segment length is 185 meters, and it relies on a bus topology.
F-connectors
A connector used to terminate coaxial cable used for transmitting television and broadband cable signals.
BNC (Bayonet Neill-Concelman, or British Naval Connector)
A standard for coaxial cable connectors named after its coupling method and it inventors.
BNC connector
A coaxial cable connector type that uses a turn-and-lock (or bayonet) style of coupling. It may be used with several coaxial cable types, including RG-6 and RG-59.
BNC coupler
A coupler designed to connect two coaxial cables.
10Base2
dubbed cheapernet, Thinnet, or thin wire, because it used RG-58 cabling that was thinner than the earlier RG-8 cabling. Most commonly available 10-Mbps Ethernet cable.
Twisted-pair
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. Every two wwires are twisted around each other to form pais, and all the pairs are encased in a plastic sheath
twist ratio
The number of twists per meter or foot in a twisted-pair cable.
Cat (category)
types of twisted-pair wiring and most common is Cat (3, 5,5e, 6, 6a and 7)
repeater
A device used to regenerate a digital signal in it original form. Repeaters operate at teh Physical layer of the OSI model.
Gigabit Ethernet
A type of Ethernet network that is capable of 1000-Mbps, or 1-Gbps, througput. Requires Cat 5e or higher cabling.
Cat 3 (Category 3)
An outdated form of UTP that contained four wire pairs and could 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.
Cat 5 (Category 5)
A form of UPT that contains four wire pairs and supports up to 100-Mbps throughput and a 100-MHz signal rate. Required minimum standard for Fast Ethernet.
Cat 5e (Enhanced Category 5)
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 that trople the capability of regula
Cat 6 (Category 6)
A twisted-pair cable that cintains four wire pairs, each wrapped in foil insulation. Additional foil insulation can cover the bundle of wire pairs, and a fireresistant plastic sheath meight cover the second foil layer. The foil insulation provides excelle
Cat 6a (Augmented Category 6)
A higher-grade version of Cat 6 wiring that further reduces attenuation and cross-talk, and allows for potenially exceeding exceeding traditional network segment length limits. Cat 6a is capable of a 500-MHz signaling rate and can reliably transmit data a
Cat 7 (Category 7)
A twisted-pair cable that contains multiple wire pairs, each separately shielded then surrounded by another layer of shielding within the jacket. Cat 7 can support up to a 600-MHz signal rate. But because of it extra layers, it is less flexible than other
Cat 7a (Augmented Category 7)
A higher-grade version of Cat 7 wiring that will possibly support up to 100-Gbps throughput and up to 1000-MHz signal rate. ISO standards for Cat 7 a cabling are still being drafted and simulations conducted.
Rj-45 (registered jack 45)
The standard connector used with shielded twisted-pair and unshielded twisted-pair cabling.
Rj-11 (registered jack 11)
The standard connector used with unshielded twisted-pair cabling (usually Cat 3) to connect analog telephones.
10Base-T
A Physical layer standard for networds that specifies baseband transmission, twisted-apir cabling, and 10-Mbps throughput. 10Base-T netwokds have a maximum segment length of 100 meters and rely on a star topology.
100Base-T Fast Ethernet
A Physical layer standard for network that specifies baseband transmission, twisted-pair cabling, and 100-Mbps througput. 100Base-T networks have a maximum segment length of 100 meters and use the star topology. 100Base-T is also known as Fast Ethernet.
1000Base-T
A Physical layer standard for achieving 1 Gbps over UPT. 1000Base-T achieves its higher throughput by using all four pairs of wires in a Cat 5 or better twisted-pair cable to both transmit and receive signals. 1000Base-T also uses a different data encodin
1000Base-TX
A Physical layer standard for networks that achieves 1 Gbps over Cat 6 or better cabling using only two paris of wires.
10GBase-T or 10-Gigabit Ethernet
A Physical layer standard for achieving 10-Gbps data transmission over twisted-pair cable. Described in its 802.3an standard, IEEE specifies Cat 6 or Cat 7 cable as the appropriate medium for 10Gbase-T. The maximum segment length for 10GBase-T is 100 mete
pinouts
The pin numbers and color-coded wire assignments determined by the TIA/EIA standard used when terminating a cable or installing a jack. The two standards definded for Ethernet, of example, are TIA/EIA 568A and TIA/EIA 568B.
straight-through cable
A twisted-pair patch cable in which the wire terminations in both connectors follow the same scheme.
crossover cable
A twisted-pair patch cable in which the termination locations of the transmit and receive wires on one end of the cable are revered as compared with the other end. A crossover cable is used to connect a PC to a PC, a switch to a switch, or a PC to a route
rollover cable
A twisted-pair patch cable in which all of the wires are reversed on one end of the cables as compared with the other end without regard to how they are paired. A rollover cable is used to connect a computer to the console port of a router. Also called Yo
Yost cables or Cisco console cables
can be used to connect a computer to the console port of a router.
Ethernet ports
allow for network communication and are the type of port used to create LANs through the router.
console port
is used to communicate with the router itself, such as when making programming changes to the devices.
wire stripper
is designed to pull the protective covering off the inside wires without damaging the wires themselves.
crimping tool or cable crimper
causes the internal RJ-45 pins to pierce the insulation of the wire, thus creating contact between the two conductors.
crimping
the process of fixing wires inside the connector
connector
The piece of hardware that connects a wire to a network device, be it a file server, workstation, switch, or printer.
media converter
- is hardware that enables networks or segments running on different media to interconnect and exchange signals.
- A device that enables networks or segments running on different media to interconnect and exchange signals.
coupler
A simple kind of connector that passes data through a homogenous connection without frames. Most often, CoS is used to more efficiently route Ethernet traffic between VLANs.
UTP coupler
A connector that can connect two UTP cables to each other. This is helpful when needing to lengthen a cable without installing a new, longer cable.
802.3af
The IEEE standard that specifies a way of suppluing electrical power over twisted-pair Ethernet connections, also known as PoE (power over Ethernet). 802.3af requires Cat 5 or better UTP or STP cabling and uses power sourcing equipment to supply current o
PoE (Power over Ethernet)
A method of delivering current, usually 15.4 watts, to devices using Ethernet connection cables.
PoE+
A method of delivering more current (25.5 watts) than PoE does to devices using Ethernet connection cables.
802.3at
The IEEE standard that improves upon the older 802.3af by supplying more power over Ethernet connections. Whereas PoE supplies about 15.4 watts for standard PoE devices, PoE+ provides about 25.5 watts.
PSE (power sourcing equipment)
On a network using Power over Ethernet, the device that supplies power to end nodes.
PDs (powered devices)
On a network using Power over Ethernet, a node that receives power from power sourcing equipment.
RS-232 (Recommended Standard 232)
A Physical layer standard for serial communications, as defined by TIA/EIA.
DB-9 connectors
A type of connector with nine pins that's used in serial communication and conforms to the RS-232 standard.
DB-25 connectors
A type of connector with 25 pins that's used in serial communication and conforms to the RS-232 stardard.
core
A cable's central component, 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.
LED (light-emitting diode)
A cool-burning, long-lasting technology that creates light by the release of photons as electrons move through a semiconductor material.
cladding
the glass or plastic shield around the core of a fiber-optic cable. Cladding reflects light back to the core in patterns that very depending on the transmission mode. This relfection allows fiver to bend around corners without impairing the light-bassed s
zipcord cable
A relatively short fiber-optic cable in which two strands are arranged side by side in conjoined jackets, enabling full-duplex communication.
optical loss
The degradation of a light signal on a fiber-optic network as it travels away from its source.
SMF (single mode fiber)
A type of fiber-optic cable with a narrow core of 8 to 10 microns in diameter that carries light pulses along a single path 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 mu
MMF (Multimode Fiber)
A type of fiber-optic cable containing a core that is usually 50 or 62.5 microns in diameter, over which many pulses of light generated by a laser or lightemitting diode (LED) travel at different angles.
ferrule
The extended tip of a fiber-optic cable connector that encircle the fiber strand to keep it properly aligned and ensure that it makes contact with the receptacle in a jack or other connector.
back reflection
The return of a light signal back into the fiber that is transmitting the signal. Back relfection is measured as optical loss in dB (decibels)
Physical Contact (PC)
The early generation of ferrule is curved, which allow the two fibers to meet
Ultra Polished Connector (UPC)
Extensive polishing of the tips which increase efficiency through the connection.
Angle Polished Connector (APC)
the latest advancement in ferrule teachnology yses the principles of reflection to its advantage. The Angle Pilished Connector (APC) still used a polished curved surface, but the end faces are placed at an angle to each other.
LC (local connector)
most common 1.25-mm ferrule connector, polish = PC, UPC, APC and yes Full-duplex.
SC (subscriber connector or standard connector)
three 2.5-mm ferrules, polish = PC, UPC, APC and both single or multiplex
ST (straight tip)
2.5-mm ferrules, polish = PC, UPC and not Full-duplex
FC (ferrule connector or fiber channel)
2.5-mm ferrules, polish = PC, UPC, APC and yes Full-duplex
MT-RJ (Mechanical Transfer-Registered Jack)
most common type with 2 fibers and yes Full-duplex and no polish
fiber couplers
A simple fiber connector that can be used to connect like terminations, such as when joining two shorter cables to make a longer one. Some fiber couplers can also combine signals from multiple lines into a single line.
snips
A synonym for scissors
boot
A pllastic cover designed to protect the strands at the end of a cable where the strands enter a connector.
regeneration
The process of retransmitting a digital signal. Regeneration, inlike amplification, repeats the pure signal, with none of the noise it has accumulated.
backplane
A synonym for motherboard, often used in the contect of switches and router
hot-swappable
The feature of a component that allows it to be installed or removed without disrupting operations.
GBIC (Gigabit interface converter)
A standard type of modular interface designed in the 1990s for Gigabit Ethernet connections. GBICs may contain RJ-45 or fiber-optic cable (such as Lc, SC, or ST). They are inserted into a socket on a connectivity device's backplane.
SFP (small form-factor pluggable) transceivers
mini GBICs
SFP GBICs
A standard hot-swappable network interface used to link a connectivity device's backplane with fiber-optic or copper cabling. SFPs are known as mini GBIC because they perform a similar function as GBIC, but have a small profile. Current SFP standards enab
XFP
A type of SFP that can send and receive data at rates of up to 10 Gbps
SFP+
A type of SFP that can send and receive data at rates of up to 10 Gbps
100Base-FX
A largely outdate physical layer standard for networks that specifies baseband transmission, multimode fiber cabling, and 100-Mbps throughput. 100Base-FX is the fiber version of Fast Ethernet.
1000Base-LX
A Physical layer standard for networks that specifies 1-Gbps transmission over fiber-optic cable using baseband transmission. 100Base-LX is a common fiber version of Gigabit Ethernet and can run on either signle-mode or multimode fiber. The LX represents
1000Base-SX
A Physical layer standard for networks that specifies 1-Gbps transmission over fiber-optic cable using baseband transmission. 1000Base-SX runs on multimode fiber. The SX represents its reliance on short wavelehgths of 850 nanometers.
Modal bandwidth
A measure of the highest frequency of signal a multimode fiber-optic cable can support over a specific distance. Modal bandwidth is measured in MHz-km.
802.3ae
The IEEE standard that describes 10-Gigabit Ethernet technologies, including 10GBase-SR, 10GBase-SW, 10GBase-LR, 10GBase-LW, 10GBase-ER, and 10GBase-EW
NSPs (network service providers)
A carrier that provides long distance (and often global) connectivity between major data switching centers across the Internet. AT&T, Verizon, and Sprint are all examples of network service providers in the United States. Customers, including ISPs, can le
10GBase-SR
A Physical layer standard for achieving, 10-Gbps data transmission over multimode fiber using wavelengths of 850 nanometers. 10GBase-SR is designed to work with LANs. The maximum segment length for 10GBase-SR can reach up to 300 meters, depending on the f
10GBase-SW
A variation of the 10GBase-SR standard that is specially encoded to operate over SONET-based WAN links.
10GBase-LR
A Physical layer standard for achieving 10-Gbps data transmission over single-mode, fiber-optic cable using wavelengths of 1310 nanometers. In 10GBase-LR, the LR stands for long reach. This standard specifies a star topology and segment lengths up to 10,0
10GBase-LW
A variation of the 10GBase-LR standard that is specially encoded to operate over SONET-based WAN links.
10GBase-ER
A Physical layer standard for achieving 10-Gbps data transmission over single-mode, fiber-optic cable. In 10GBse-ER, the ER stands for extended reach. This standard specifies a star topology and segment lengths up to 40,000 meters.
10GBase-EW
A variation of the 10GBase-ER standard that is specially encoded to operate over SONET-based WAN link.
RFI (radio frequency interference)
electromagnetic interference caused by radio waves.
Cross-talk
A type of interference caused by signals traveling on nearby wire pairs infringing on another pair's signal.
split pair
A problem created when wires from different twisted pairs in twisted-pair cable are improperly yoked together, rather than wiring twisted pairs together according to the appropriate pinout.
alien cross-talk
Electromagnetic interference induced on one cable by signals traveling over a nearby cable.
near end cross-talk (NEXT)
Cross-talk that occurs between wire pairs near the source of a signal
far end cross-talk (FEXT)
Cross-talk measured at the far end of the cable from the signal source.
Tx/Rx reverse.
A problem caused by mismatched pinout standards, resulting in near end cross-talk.
attenuation
The loss of a signal's strength as it travels away from its source.
amplifier
A device that increase the voltage, or strength, of an analog signal.
RTT (round trip time or real transfer time)
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.
fiber type mismatch
A problem created by mismatching fiber core types, such as when connecting an SMF cable to an MMF cable.
wavelength mismatch
A problem created when transmissions are optimized for one type of cable, such as SMF, but sent over a different type of cable, such as MMF.
tone generator or toner
A small electronic ddevice that issues a signal on a wire pair. When ised in conjunction with a tone locator, it can help locate the termination of a wire pair.
tone locator or probe
A small electronic device that emits a tone when it detects electrical activity on a wire pair. When used in conjection with a tone generator, it can help locate the termination of a wire pair.
toner and probe kit or toner probe
this is the store brand name
multimeter
is a simple instrument that can measure many characteristics of an electric circuit, including its resistance, voltage, and impedance.
short circuit
is an unqanted connection, such as when exposed wires touch each other
open circuit
is one where needed connections are missing, such as when a wire breaks.
cable checkers
continuity testers
is a tool used to test the continuity of the cable.
cable tester
A device that tests cables for one or more of the following conditions: continuity, segment length, distance to a fault, attenuation along a cable, near-end cross-talk, and termination resistance and impedance. Cable testers may also issue pass/fail ratin
cable performance tester
A troubleshooting tool that tests cables for continuity, but can also measure cross-talk, attenuation, and impedance; identify the location of faults; and store or print cable testing results. Also called line tester, certified, or network tester.
line tester
cable performance tester
certifier
cable performance tester
TDR (time domain reflectometer)
A high-end instrument for testing the qualities of a cable. It works by issuing a signal on a cable and measuring the way in which the signal bounces back (or reflects) to the TDR. Many performance testers rely on TDRs.
OTDRs (optical time domain reflectometers)
A performance testing device for use with fiber-optic networks. An OTDR works by issuing a light-based signal on a fiber-optic cable and measuring the way in which the signal bounces back (or reflects) to the OTDR. Based on the type of return light signal
optical power meter (OPM)
A device that measures the amount of light power transmitted on a fiber-optic line. Also called laser power meter or light meter.
NIST (National Institute of Standards and Technology)
A nonregulatory agency of the U.S Department of Commerce that sets many technology standards.