##|A|B|C|D|E|F|G|H|I|L|M|N|O|P|R|S|T|U|W
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1000Base-LX/FX - Gigabit Ethernet over fibre optic cable
1000Base-T - 1000Mbps, 1 billion bits per second over copper cabling. All four pairs of Cat6 cable utilised at 250Mbps per pair
100Base-FX - 100 Mbps Ethernet data transmissions over Fibre Optic cable
100Base-LX - 1300nm - Long wavelength fibre optic transmissions at 100 Mbps
100Base-SX - 850nm - Short wavelength fibre optic transmissions at 100 Mbps
10BaseT - 10 Mbps Ethernet running baseband signalling over twisted pair copper cable
9/125 micron - The common size of Single-Mode fibre optic cables
50/125 micron - One of two common sizes of Multimode fibre optic cables
62.5/125 micron - One of two common sizes of Multimode fibre optic cables
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A
ACR - Attenuation to Crosstalk Ratio. The level of cross talk in relationship to the attenuated signal at the far end of the cable. Critical in Full Duplex mode
ADSL - Asymmetric Digital Subscriber Line. A digital connection with higher bandwidth for downloading than uploading
Attenuation -The reduction in optical power as it passes along a fiber, usually expressed in decibels (dB). See optical loss
AWG - American Wire Gauge. The larger the number, the smaller the wire diameter
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B
Bandwidth - The range of signal frequencies or bit rate within which a fiber optic component, link or network will operate.
Baseband - The raw data is transmitted using the full bandwidth of the cable with no modulation
BNC - Bayonet connector used with RG58 coaxial cable networks. Thin Ethernet
bps - Bits per second
Broadband - The bandwidth of the cable is split into multiple modulated channels. Guard bands are used to separate the channels
Broadcast - To send data to more than one device at a time
Bus Network - A network with all devices sharing one common cable
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C
CAT5 - 100 MHz Category 5 data cabling as specified by the EIA/TIA standards authority
CAT5 E - Enhanced Cat 5 data cabling with more stringent tests and headroom. Still 100Mhz
Category 5, Cat5 - UTP 100 ohm for frequencies up to 100Mbs defined by TAI/EIA 568-A specifications
Category 5E, Cat5E - Enhanced Cat5. Similar to Cat5 with improved specifications including PSELFEXT, ACR and attenuation. Defined by EIA/TIA 568-A-5
Category 6,Cat6 - Proposed cabling standard to support up to 250 MHz over UTP. Not yet ratified
Category 7, Cat7 - Proposed cabling standard to support up to 600 MHz over UTP
Coax - Coaxial cable with a copper screen carrying unbalanced signals
Core - The center of the fiber where the light is transmitted.
Crosstalk - interference picked up from an adjacent wire pair within the same cable (see also alien crosstalk)
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D
D' Type D' - Shaped connector with an array of pins in 9, 15 and 25
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E
EIA - Electronics Industry Association in America
EIA 568 - UTP commercial building specifications from the EIA
EIA 568B - Now the most common UTP cable colour codes and pin allocation
ELFEXT - Equal Level Far End Cross Talk
EMI - Electro Magnetic Interference. Unwanted noise from a source such as fluorescent lighting and electric motors
Ethernet - A LAN protocol in which computers access the network through CSMA/CD protocols defined by the IEEE 802.3 standards. Invented by Rank Xerox
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F
Fast Ethernet - 100Mbps CSMA/CD Ethernet
FDDI - Fibre Distributed Data Interface as defined by (ANSI X3T12) for 100Mbs token passing over Fibre
Full duplex - Allows data transmissions in two directions at once. Transmit and receive simultaneously
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G
Gbps - Giga bits per second. 1 billion or 1,000,000,000 bits per second
Gigabit Ethernet - 1000Mbps, 1 Billion bits per second over copper cabling
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H
Half Duplex - Single way transmission. Is capable of both Transmitting and Receiving but not simultaneously
Headroom - The amount by which a network cable ACR exceeds 10dB above the specification
Horizontal Cabling - The structured cabling which connects the wall sockets to the network cabinet or wiring closet
Hub - The centre of a star wired network. May be passive or active in re-transmissions of network traffic
Hz - Frequency per second
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I
IEEE - Institute of Electrical & Electronic Engineers
Impedance - Measurement of the opposition to the flow of electrons in a cable. The combination of Resistance, Capacitance & Inductance
Infrastructure - The collection of communication components (excluding active equipment) that together provide support for the distribution of information within a building or campus
Insertion Loss - The attenuation of a signal as it passes through a connector
Intranet - A large private company network often spanning many countries
IP - Internet Protocol. Along with TCP is used to track and deliver data packets over a network
ISDN - Integrated Digital Network Services. High speed data transfer over the PSN
ISO - International Standards Organisation
ISP - Internet Service Provider. The company who provides a connection to the internet
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L
LAN - Local Area Network
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M
MAN - Metropolitan Area Networks, Spanning a Town or City
Media - The physical wire of fibre for the transmission of signals
Miss-Wire - Where the single wires in a UTP cable have been attached to the connector in the wrong sequence
Mode - A single electromagnetic field pattern (think of a ray of light) that travels in fiber.
Modem - A device which modulates & demodulate the signals between digital to analogue circuits
Multi mode - Fibre optic cable which supports the propagation of multiple wavelengths Diameter of 50 to 100 microns with a stepped refractive index. Can use inexpensive LED light sources
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N
N Connector - Connectors used for thick Ethernet 10Base-5 coax cable
NEXT - Near End Cross Talk. The effect of one cable pairs signal on the adjacent pairs
Numerical Aperture - The angle at which a fibre will gather light and propagate it down the core
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O
OTDR - Optical Time Domain Reflectometer. A device for finding breaks in fibre optic cables or measuring the length
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P
PABX - Private Automatic Branch Exchange, A switchboard, (PBX)
Packet - A string of bits containing command information, destination and source addresses and data
Patch Cable - The cable connecting the network panel and the active switch or hub.
Patch panel - An array of connectors in the network cabinet to allow circuit rearrangements by plugging in patch cords
Physical layer - Layer one of the seven OSI layers. This layer is responsible for the transmission of signals between computers
POP - Point of Presence. The connection point to the internet
Premises cabling - The complete cabling infrastructure for the transmission of voice, data and video through out a given building
Propagation delay - The time for a signal to travel from input to the output of a device
Protocol - A data transfer mode using Bit codes, Start Stop bits, Parity. Both transmitter and receiver must use the same protocols
PSELFEXT - Power Sum Equal Level Far End Cross (X) Talk. Measures the summed cross talk from 3 pairs on the remaining pair having compensated for the known attenuation of the cable
PSNEXT - Power Sum Near End Cross Talk. The effect on one pair of the summed crosstalk of the three other pairs
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R
Reflection - The return of electromagnetic energy that occurs when components are mismatched in network cabling. These reflections can cause data errors
Reversed Pairs - The most common miss wire where the single wires in a pair have been reversed
RFI - Radio Frequency Interference
RG 58 - The specification of the coaxial cabled used for thin Ethernet networks
Ring Topology - Describes a network in a complete ring. Now the fastest and most resilient network
RJ11 - Registered Jack number 11. Small line plug and socket used on telephone handsets and modem connections
RJ45 - Registered Jack number 45. 8 pin plug and socket
RS232 - Robust but outdated signalling protocol using 2 pairs
RX - Receive
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S
SC connector - A connecter for terminating fibre optic cables. Can be snapped together to form a duplex connector for RX and TX transmissions
Shielded - Cable with a braided or foil shield to keep out RFI and EMI
Single-Mode - An optical fibre that supports only one mode of light propagation above the cutoff wavelength. The core diameters are usually between 5 and 10 microns
Skew - The differential delay between two adjacent cables carrying data transmitted simultaneously
Split Pairs - Where the single wires from two different pairs have been swapped. If the same at both ends will not affect short cable transmissions, but will fail over longer distance. A common fault
ST connector - Straight Tip. A connector registered to AT&T for fibre optic terminations
Star Topology - All devices are attached to a central hub in a star configuration
STP - Shielded Twisted Pair copper cable
Structured cabling - The fixed solid core cabling which makes up the building wiring
Switch- An Ethernet active repeater which reads MAC addresses and routes data to the individual node or network hub. Switches split up networks into smaller individual collision domains. A switch can route data at wire speed through all it's ports simultaneously
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T
TCP - Transmission Control Protocol. Used with IP to track and deliver packets of data over a network
TDR - Time Domain Reflectometer. A device for measuring the length of cables by "bouncing" a signal off the far end. The NVP must be known and programmed into the machine
Terminator - An electrical connector attached to the end of a cable to reduce signal reflections and unwanted noise
TIA - Telecommunication Industry Association
TIA 568A-4 - The TIA Category 5E Specifications
Token Ring - A network where a single token is passed around a network between computers. A computer must grab and hold onto the token before it can transmit. After transmission it releases the token back onto the network
Topology - Network architecture, circuit design and transmission protocols
Transceiver - An electronic circuit designer to transmit and receive data over a network. A NIC contains a transceiver as does a hub and a switch
Twisted Pair - Pairs of 26 AWG wires twisted together the reduce RFI and Crosstalk
TX - Transmit
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U
UTP - Unshielded Twisted Pair. 4 twisted pairs in one sheath
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W
WAN - Wide Area Network
