Fbier Optic

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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

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