Note: This is a so far incomplete glossary for ITE1. It isn't spellchecked, but everything of note is
in it up to and including the end of chapter 8. Feel free to share, and I hope this helps. Thanks,
Luke.
ITE1
Glossary
Chapter 1: Hardware
UPS: Uninteruptable Power Supply. Device to prevent fluctuations in electricity, power flows
from wall socket to a battery then to the device. Don't attach to printers.
CPU: Central Processing Unit. Often called the brain of the computer, a chip that does many of
the calculations for the opperation of the computer.
Chipset: Group of integrated circuits on a motherboard that allows the CPU to communicate
with everything else. Also determines how much ram can be installed and the type of
connectors present.
AT: Advanced Technology. Form factor for motherboards by IBM. Old and large.
ATX: Advanced Technology Extended. Form factor for motherboards designed to integrate the
ports of the AT form factor into a smaller physical space.
Mini-ATX: Form factor for motherboards, smaller version of Advanced Technology Extended.
Micro-ATX: Form factor for motherboards, smaller version of advanced technology extended.
LPX: low profile extended. Form factor for motherboards.
NLX: New Low Profile Extended. Form factor for motherboards.
BTX: Balance Technology Extended. Form factor for motherboards.
PGA: Pin Grid Array. An architecture of socket where the pins on the socket fit into holes on the
motherboard. Most common in use.
ZIF: Zero Insertion Force. A means of inserting a processor whereby the processor doesn't need
to be pushed down to connect with the socket.
RISC: Reduced Instruction Set Computer. CPU architecture relating to instruction sets where
relatively small instruction sets are executed very rapidly.
CISC: Complex Instruction Set Computer. CPU Architecture relating to instruction sets where a
broader set of instructions are executed with fewer steps per opperation.
Hyperthreading: A process where a processor can execute more than one piece of code at once,
thus making it look like 2 CPUs to the opperating system.
FSB: Front Side Bus. Also called the Processor Data Bus or the CPU Bus. The width of this
controls the amount of data a CPU can process at one time, currently 32-bit or 64-bit.
MMX: Set of multimedia instructions built into Intel chips that allows an MMX capable
Microprocessor to perform many of the functions of a separate sound of video card. Note only
some software can access these instructions.
SSE: Streaming Single-instruction-multi-data Extensions. An enhancement to the instruction set
of Intel Processors that has replaced MMX. Several versions are available with different
instructions.
GPU: Graphics Proccessing Unit. A specific processor attached to some graphics cards to help
unburden the CPU.
ROM: Read-Only Memory. A kind of chip found on the motherboard that is used for storing
instructions that are used directly by the CPU, the contents of which cannot be changed. These
include instructions for booting the computer and loading the opperating system.
Firmware: The software that is installed in a ROM chip.
RAM: Random Access Memory. This is where programs and data being used by the CPU are
temporarily storred. This information is not saved when the RAM is no longer recieving power.
DIP: Dual Inline Package. A Dual Inline Package Chip is old memory that was installed directly on
the motherboard, rather than soldered to a memory module.
PROM: Programmable Read-Only Memory. A kind of ROM chip that is programmed after it's
manufacture and cannot be rewritten or erased.
EPROM: Erasable Programmable Read-Only Memory. A kind of Rom Chip that is programmed
after it's manufacture, but it's contents can be erased and changed by exposure to UV light.
EEPROM: Electrically Erasable Programmable Read-Only Memory. Also called Flash ROM's. A
chip in which information is written after it's manufacture, but it can be rewritten without
removing the chip from the computer.
DRAM: Dynamic RAM. A chip used for main memory that must be constantly refreshed with
pulses of electricity to maintain the data on the chip.
SRAM: Static RAM. This is a chip used for cache memory, being faster than DRAM and not
needing to be refreshed as often.
FPM: Fast Page Mode. This is a type of RAM that supports paging, allowing data to be accessed
faster than from Dynamic RAM.
EDO Memory: Extended Data Out Memory. This is a kind of Ram that allows for faster data
retrieval as it allows the data cycles to overlap, meaning the processor doesn't have to wait for
one to finish before starting the next.
SDRAM: Sincrynous Dynamic RAM. A kind of chip which opperates in sincrynisation with the
Memory Bus, the data path between this chip and the processor.
DDR SDRAM: Double Data Rate Sincrynised Dynamic RAM. A memory chip that transferrs data
twice as fast as Sincrynous Dynamic RAM by transferring twice per data cycle.
DDR2 SDRAM: Double Data Rate 2 Sincrynous Dynamic RAM. This is a chip that is faster than
Double Data Rate Sincrynous Dynamic RAM as it decreases interference or crosstalk between
the signal wires.
RDRAM: RAMbus Dynamic RAM. This is a chip that was designed to communicate at very high
speeds, but is rarely used.
SIMM: Single Inline Memory Module. A small circuit board that holds several memory chips.
These have 32 and 72 pin configurations.
DIMM: Dual Inline Memory Module. This is a circuit board that holds Sincrynous Dynamic RAM,
Double Data Rate Sincrynous Dynamic RAM, or Double Data Rate 2 Sincrynous Dynamic RAM
chips. Depending on the chips used they either have 168, 184, or 249 pins, respectively.
RIMM: RAM Bus Inline Memory Module. This is a circuit board that is used to hold RAM Bus
Dynamic Ram Chips and typically has a 184 pin configuration.
SODIMM: Small Outline Dual Inline Memory Module. This is a circuit board with either a 72 pin
configuration for 32-bit transfers or a 144 pin configuration for 64-bit transfers. It is a smaller
version of a Dual Inline Memory Module ideal for use in laptops or printers.
NIC: Network Interface Card. An adaptor card that allows a computer to connect to the internet
by cable or wireless depending on the capabilities of the card.
SCSI: Small Computer System Interface. A type of connection that can be used to connect
computers to an array of peripherals, including hard drives and tape drives. It uses either a 50,
68, or 80 pin connector.
RAID: Redundant Array Of Independent Discs. This is an adaptor card that is installed in a
computer. It is a system that allows data to be storred across multiple hard drives allowing for
redundency if a drive fails. Different levels of RAID are set up differently and have different
characteristics , but under RAID the opperating system will see the different drives as one logical
disk.
USB: Universal Serial Bus. This is an interface that allows computers to connect with an array of
peripherals including hard drives and keyboards. This interface is hot swappable and may
provide power.
ISA: Industry Standard Architecture. This is a type of 8-bit or 16-bit expansion slot on a
motherboard for adaptor cards, but is older technology and not used.
EISA: Extended Industry Standard Architecture. This is a 32-bit expansion slot for adaptor cards
that is no longer used.
MCA: Microchannel Architecture. A proprietary 32-bit expansion slot for adaptor cards by IBM
that is now out of date and seldom used.
PCI: Peripheral Component Interconnect. This is a 32-bit or 64-bit expansion slot used in most
computers.
AGP: Advanced Graphics Port. This is a 32-bit expansion slot designed for graphics cards.
PCI Express: Peripherial Component Interconnect Express. This is an expansion slot designed to
expand the serial bus, and is backwards compatable with devices that connect to a PCI slot.
SSD: Solid State Drive. A hard drive that stores information on non-volatile flash chips rather
than magnetic platters.
CD: Compact Disc.
DVD: Digital Versitile Disc.
BD: Blu-ray Disc.
CD-ROM: CD Read Only Memory. Media that is pre-recorded.
CD-R: CD recordable. Media that can be recorded once.
CD-RW: CD Rewritable. Media that can be recorded, erased, and rerecorded.
DVD-ROM: DVD Read-Only Memory. Media that is pre-recorded.
DVD-RAM: DVD Random Access Memory. This can be recorded, erased, and rerecorded.
DVD+/R: DVD Recordable. Media that can be recorded once.
DVD+/-R: DVD rewritable. DVD media that can be recorded, erased, and rerecorded.
BD-Rom: BD Read-Only Memory. Pre-recorded usually with movies or games.
BD-R BD recordable. BD media that can be recorded once.
BD-RE: BD rewritable. BD media that can be recorded and erased.
IDE: Integrated Drive Electronics. This is an early drive controler that uses a 40 pin connector
and is also caled ATA.
ATA: Advanced Technology Attachment. This is an old drive controler used to attach hard drives
in computers, also called IDE.
EIDE: Enhanced Integrated Drive Electronics. This is an update to the original IDE controler, still
using a 40 pin connector, sometimes called ATA2 that encorporates support for optical and tape
drives and extra speed.
DMA: Direct Memory Access. One of the kinds of system resources. Introduced with the EIDE
interface this increases the speed of data transfer to and from internal drives. This resource
allows high speed devices to communicate directly with the RAM, bipassing the processor
entirely to gain information.
ATAPI: AT Attachment Packet Interface. Allows the use of optical drives and tape drives on the
EIDE bus.
PATA: Parallel ATA. Parallel version of the ATA drive controler interface.
SATA: Serial version of the ATA drive controler interface. Newer and supports bigger drives and
uses a 7 pin data cable.
eSATA: External Serial ATA. This allows a SATA drive to be connected externally with a 7 pin data
cable with the same speed as an internal drive. This interface is also hot-swappable, but
provides no power to the disc.
Berg Connector: 4-pin power connector used to power a 3.5 inch floppy drive.
Molex Connector: A power cable designed to connect to PATA drives and optical drives.
FDD Data Cable: Floppy Disc Drive Data Cable. Cable that uses 34 pin connectors to connect
floppy disc drives to the drive interface.
RJ-9: Connector used to connect a phone to a wall socket.
RJ-11: Connector used to connect a modem to a phoneline.
RJ-45: connector used to connect a computer to a network.
IEEe 1394: The standard used by FireWire, also known as i.link, a high speed, hot swappable
interface used to connect peripherals to a computer. IEEE 1394A uses a 4 or 6 pin connector
with cable lengths of up to 4.5 meters where IEEE 1394B supports a greater range of
connections including category 5 unshielded twisted pair and cable lengths up to 100 meters, as
well as higher speeds.
IEEE 1284: The standard used for connections to parallel cables, used to connect printers etc.
PS/2 port: 6 pin port used to connect a mouse or keyboard to a computer.
S/PDIF: Sony/Philips digital interface format. A port used to connect to fiber optic cable to
support digital audio.
TosLink: Port that connects to coaxial cable to support digital audio.
VGA: Video Graphics Array. 15 pin port that connects to a monitor providing analog output.
DVI: Digital Visual Interface. Either a 24 or 29 pin port which provides uncompressed digital
output to a monitor. DVI-I provides both digital and analog signals where DVI-D provides only
digital.
HDMi: High Definition Multimedia Interface. 19 pin port that provides both digital audio and
digital video signals.
Component/RGB: Red Green, Blue. This is a port with 3 shielded cables of the above colours
with RCA jacks which provides analog video signals.
KVM Switch: Keyboard, Video, Mouse switch. This is a hardware device that is used to control
more than one computer with only one mouse, keyboard, and monitor.
CRT: Cathode-Ray Tube. This is the traditional computer monitor or television that has 3
electron beams that direct coloured phosphor on the screen in a mixture of red, green, and
blue, with areas not struck by a beam not glowing.
LCD: Liquid Crystal Display. The screens of most laptops and some projectors, where 2 polarising
filters sandwich a liquid crystal layer. These crystals can be arranged by an electrical current for
light to pass through or not forming the image.
TFT: Thin Film Transistor. Also called Active matrix, it is a method where each pixel of an LCD
monitor to be controled, as opposed to Passive matrix which is cheaper but has less image
control.
DLP: Digital Light Porcessing. This is a technology used in the screens of some projectors where
mirrors reflect light towards or away from the screen for each pixel, controled by a
microprocessor array.
DMD: Digital Micromirror Device. This is the array of mirrors in a DLP projector screen.
IRQ: Interupt Request. This is one of the kinds of system resources used by a computer.
Specifically a request from a component of the computer for information from the processor.
I/O address: Input/Output port address. One of the kinds of system resources used by a
computer. This resource is what allows components and software to communicate with each
other.
Chapter 2, Workplace Safety
ESD: Electrostatic Discharge. This is where static electricity jumps from one thing to another.
EMI: Electromagnetic Interference. This is where outside electromagnetic signals intrude into a
transmission medium such as copper cabling.
RFI: Radio Frequency Interference. This is where outside radio signals interfere with wireless
networks, by being on the same frequency for example.
SPS: Standby Power Supply. This is a device that helps to negate the effects of unreliable power
supplies by switching its power output to a battery when the power dropps below 100% Note
this is different to a UPS as the battery is not opperating all the time and only cuts in when
needed.
MSDS: Material Safety and Data Sheet. This is a sheet detailing what dangerous materials are
present and what should be done with them to dispose of them safely.
Chapter 3: Computer assembly
HDD: Hard Disk Drive. This is a drive installed in a computer that holds the files and applications.
FDD: Floppy Disc Drive. A drive designed to take and read 3.5 inch floppy discs.
BIOS: Basic Input and Output System. This is the system that allows a user to interact with the
computer before the opperating system is loaded. Basic settings can be changed including the
boot order etc.
POST: Power On Self Test. A test of the hardware components performed by the BIOS before it
loads the opperating system.
CMOS: Complimentary Metal Oxide Semiconductor. The chip where the BIOS configuration data
is saved. This chip is powered by a battery on the motherboard.
Chapter 4: Trouble Shooting
Chapter 5: Opperating Systems
OS: Opperating System. The program that controls almost all the functions of a computer.
GUI: Graphical User Interface. A method of navigating through a computer or program formed
out of graphical elements such as buttons, links, treeviews etc.
CLI: Command Line Interface. A method of interacting with a computer or program that relies on
entering commands into a text edit field.
PNP: Plug And Play. A process introduced in Windows 95 that allows an opperating system to
automatically detect and install device drivers.
API: Application Programming Interface. A set of guidelines used by programmers to ensure that
an application is compatable with a target opperating system.
Open GL: Open Graphics Library. Cross platform stand for multi-media graphics.
DirectX: Collection of API's related to multi-media tasks in windows.
NOS: Network Opperating System. This is an opperating system such as Windows Server 2008
that is designed to be used by multiple people in a corporate environment.
HCL: Hardware Compatibility List. This is a list of hardware that is compatible with an opperating
system and is generally found on the opperating system's manufacturers website.
FAT32: File Allocation Table, 32-bit. File system that can support particians up to 2 TB and is
supported by windows up to XP.
NTFS: New Technology File System. File system used by windows Vista and 7 that supports
larger particians and includes greater file system security.
ASR Set: Automated System Recovery Set. This is a set of discs that can be used to restore a
computer when other options have failed. It is an image of the opperating system, programs,
and settings that are on the hard drive.
MBR: Master Boot Record. This is found by the BIOS at startup and is used to find the main file
to load the opperating system.
NTLDR: NT Loader. This is the name of the file that loads a windows opperating system.
PC99: Standard that controls audio cabling. Under this standard green is usually the speakers,
Pink is the microphone, and grey is the line in.
WER: Windows Error Reporting. The part of windows that allows you to send an error report
when a system error occurs.
ASR Set: Automated System Recovery Set. A set of discs and files that contain information about
the system state, opperating system components, and services, as well as a file containing
information about the discs and how to use the backup.
MMC: Microsoft Management Console. This allows you to create and manage snap ins to help
with administration of certain parts of a computer.
MAP Toolkit: Microsoft Assessment and Planning Toolkit. Software designed to tell a user if
hardware and software is compatable with a newer version of windows.
USMT: User State Migration Tool. This is a piece of software used to migrate all of a users files
and settings to a new version of windows.
ERD: Emergency Repair Disk. This is the windows 2000 equivalent of the recovery disk.
DAT: Digital Audio Tape. This is a standard that uses 4 mm audio tapes to store data as a back-
up.
DLT: Digital Linear Tape. Provides high capacity and relatively high speed data storage and back-
up capabilities.
Chapter 6: Laptops
PDA: Personal Digital Assistant. Portable device that can often perform some or many of the
functions of a laptop from a unit the size of a phone.
APM: Advanced Power Management. This is an earlier form of power management used in
laptops where the BIOS controled power management settings.
ACPI: Advanced Configuration and Power Interface. This is a newer method of power
management in laptops where power management is controled by the opperating system.
WOL: Wake On Lan. This allows a computer to be woken from sleep mode by the receipt of a
certain packet of information over the network. This may require a certain cable connection
between the NIC and motherboard.
NMT: Nordic Mobile Telephone. A first generation analog standard for cell phones that was used
in Saudi Arabia and Scandinavia.
AMPS: Advanced Mobile Phone System. A first generation analog standard for mobile phones
used in America and New Zealand.
GSM: Global System for Mobile Communications. A second generation digital standard for
higher quality voice calls for mobile phones used throughout the world.
iDEN: Second generation digital standard for mobile phones used throughout North And South
America, Saudi Arabia, and parts of Asia that included a push to talk service and international
roaming.
GPRS: General Packet Radio Service. This is an interim standard for mobile phones implamented
world wide between second and third generation that included a data layer for GSM.
CDMA: Code Division Multiple Access. This is an interim standard for voice transmission on
mobile phones implemented between first and second generation as an update to the iDEN
standard.
EDGE: Enhanced Data Rates for GSM Evolution. This is an interim standard for mobile phone
communication that was implemented world wide as a data upgrade to GPRS.
UMTS: Universal Mobile Telecommunications System. This is also called 3GSM and is a third
generation standard for mobile communication that is an advanced GSM system implemented
throughout Europe, Asia, Africa, and America.
1xEV-DO: This is a third generation standard for mobile comunication implemented world wide
as an advanced CDMA telephone system.
HSDPA: High Speed Downlink Packet Access. This is a new fourth generation standard for mobile
communication and data implemented world wide as an advanced UMTS system.
Chapter 7, printers and scanners.
PPM: Pages Per Minute. The unit of speed that measures the speed of a printer.
DPI: Dots Per Inch. The measurement of the resolution of a printer, the higher the number the
clearer and sharper the printing.
MTBF: Mean Time Between Failures. The average length of time that a printer will run without
repair.
TCO: Total Cost of Ownership. This is the total cost of owning a piece of hardware, for example
the set up cost, plus ink, plus paper, plus servicing etc.
CPS: Characters Per Second. A measurement used to measure the speed of impact printers.
NLQ: Near Letter Quality. The highest quality possible in a dot matrix printer.
CMYO: cyan, magenta, yellow, and overcoat. These are the 4 sheets of ink that are used for
colour prints in a disublimation printer. The printhead makes one pass for each layer, and the
final overcoat is clear, and reduces smearing and moisture damage.
Chapter 8: Networking
LAN: Local Area Network. This is a network that is under the administrative control of one
individual or group, though all of its devices may not be in the same place.
WAN: Wide Area Network. This is a network such as the internet that is used to connect
different LANs in geographically different locations.
WLAN: Wireless Local Area Network. This kind of network is similar to a LAN but information is
transmitted wirelessly through radio waves rather than by copper cabling.
P2P: Peer to Peer. This is a kind of network that has no centralised management, with each
client computer being responsible for it’s own data, resources, and security, and no one user
being in charge of the network.
MAC Address: Media Access Control Address. This is the physical address of a piece of hardware
on a network and cannot be changed, being burnt or programmed into the NIC at the factory.
IP Address: Internet Protocol Address. This is also called the network address and is the logical
address assigned to a device by a network administrator depending on where it is placed on the
network.
DHCP: Dynamic Host Configuration Protocol. This is a software utility that allows hosts on a large
network to be easily and automatically assigned an IP address, ensuring that no 2 devices have
the same address, and that all addresses are valid.
IPV6: Internet Protocol Version 6. The new standard of IP addressing set to replace IPV4 as it
allows for many times more addresses. Instead of 4 octets, an IPV6 address will be made of 16-
bit hexidecimal numbers separated by colons. Other advantages include increased security and
data protection, as well as automatic configuration so a device can assign itself an IP address.
QoS: Quality Of Service support. This means that time sensitive data is given priority over other
data being routed through a network. This is being implemented with IPV6.
APIPA: Automatic Private IP Addressing. This opperating system feature assigns a private
address to a device if none is available from a DHCP server. It means a computer can only
communicate with others on the same network and cannot connect to the internet. The
opperating system automatically requests an IP address at 5 minute intervals until it is granted
one.
NAT: Network Address Translation. This is the process whereby a private IP address on a LAN is
translated into a public IP address that may connect to the internet. Nat allows a router to
translate many private IP addresses under the one public IP address.
TCP/IP: Transmition Control Protocol/Internet Protocol. This is also known as the internet
protocol suite and is the suite of communications protocols that govern how packets are
exchanged over the internet and similar networks. This protocol suite includes many different
protocols so is not port specific.
IPX/XPX: Internetwork Packet Exchange/Sequenced Packet Exchange. This fulfills similar
functions to the TCP/IP suite, and was employed originally in NetWare, Novell Corporations
network opperating system. The latest version of NetWare includes the TCP/IP suite. IPS/SPX is
rarely found in modern networks and like TCP/IP is not port specific.
NetBEUI: NetBIOS Extended User Interface. This is also known simply as NetBIOS, and is a small
fast protocol running on port 137,139,150 that requires no connection to the internet. It is
suitable for small peer to peer windows networks and can be used in conjunction with a
routable protocol such as TCP/IP to gain a connection to the internet.
AppleTalk: This protocol suite was designed to network Macintosh computers and contains a
comprehensive set of protocols that span the 7 layers of the OSI model. It was designed to run
over LocalTalk, the Apple physical LAN topology as well as to be used with major LAN types such
as Ethernet or Token Ring.
HTTP: Hypertext Transfer Protocol. This protocol governs how files are transferred over the
internet and runs on port 80. It is a communication protocol that establishes a request/response
connection and is the protocol used by most websites.
WWW: World Wide Web. This is the name used to describe the internet, as it is literally a vast
network between many computers all over the world.
FTP: File Transfer Protocol. This protocol runs on either port 20 or 21, and provides services for
file transfer and manipulation. It allows multiple simultanious connections to remote file
systems.
SSH: Secure Socket Host. This is a protocol that is used to connect securely to a remote
computer or network device and opperates on port 22.
TELNET. This is an application that is similar to SSH accept that transmissions are sent in clear
text so are easily analysed. Like SSH TELNET is used to connect to a remote computer.
POP3: Post office Protocol 3. This opperates on port 110 and is a protocol used to download
emails from a remote email server.
IMAP: Internet Message Access Protocol. Opperating on port 143, this is a protocol used to
download email from a remote mail server.
SMTP: Simple Mail Transfer Protocol. This opperates on port 25 and is used to send email to a
remote mail server or over a network in a TCP/IP environment. Other protocols will perform this
function if TCP/IP is not being used.
HTTPS: Hypertext Transfer Protocol Secure. This protocol is similar to HTTP but it uses
authentication and encription to secure data as it travels between the client and web server,
opperating on port 443.
DNS: Domain Name Service. This is a protocol that opperates in the application layer of the
TCP/IP suite and opperates on port 53. It allows a host or network device to translate a
hostname or web address to an IP address or back again.
ICMP: Internet Control Message Protocol. This is a protocol used by devices to send a variety of
messages about the network itself. These may include network errors, warnings of congestion,
and echo requests to see if conectivity is present.
IP: Internet Protocol. This protocol opperates in the internet layer of the TCP/IP model and
provides source and destination addressing, much like the address information on an envelope,
for a packet of data. In conjunction with routing protocols it gives packet forwarding information
from one network to another.
RIP: Routing Information Protocol. This opperates between routing devices to determine routes
that packets should be sent on when travelling from one network to another. RIP chooses a
route that enables the packet to pass through as few routing devices as possible.
ARP: Address Resolution Protocol. This protocol is used by both routers and hosts to determine
the MAC address of a device when its IP address is known.
TCP: Transmition Control Protocol. This is the protocol that is usually used for reliably moving
data over the internet. It is found in the transport layer of the TCP/IP model and contains
phacilities for end to end connection establishment, error detection and recovery, and metering
the rate of data flow into a network, and is relied on by many applications such as email clients
and web browsers.
UDP: User Datagram Protocol. This protocol offers a connectionless service for delivery of data.
It uses lower overhead than TCP, however does not provide reliability. UDP is used by such
things as network management applications, simple file transport, and network file systems, and
in practical terms, skype for transferring files. Because this protocol doesn’t establish a
connection before sending the data, there is no guarantee it will arrive, and no way to report
back to the sender if it does not.
PING: Packet Internet Groper. This is a simple commandline utility that is used to see if one
device is connected to another. It sends packets of data to a device which then sends one back
to the sending device for each one that is received.
WAP: Wireless Access Point. A piece of networking hardware that receives signals from a cable
and then transmits them wirelessly by radio waves to other devices such as computers or
printers.
UTP: Unshielded Twisted Pair. This is the most common form of network cable and has either 2
or 4 pairs of wires that are twisted to reduce EMI and RFI. This kind of cable has a maximum
range of 100 metres. It comes in several categories that depend on how many wires in the cable
and how many twists to the wires. Category 3 has 4 pairs of wires and is used for telephone
systems and 10 mbps LAN, while category 5 has 4 pairs of wires at 100 Mbps. Category 5e is the
same but with more twists, and category 6 has more twists again and sometimes a plastic
divider between the pairs of wires.
STP: Shielded Twisted Pair. This form of network cable consists of 4 pairs of wires twisted
together, with each pair then wrapped in metallic foil to reduce noise and another layer of foil
surrounding all 4 pairs. This shielding must be propperly grounded at both ends of the cable.
Coaxial Cable: This is a form of cable used both in networks and for Cable Television. It consists
of a copper core surrounded by a heavy shielding. It comes in several types including Thicknet or
10BASE5 cable, used in networks with a maximum length of 500 meters and opperated at 10
Mbps, 10BASE2 or Thinnet, similar to Thicknet but with a maximum length of 185 metres, RG-
59, commonly used in cable television, and RG-6, a higher quality version of RG59.
Fiber-Optic Cable: a kind of network cable that uses glass or plastic fibers to transmit signals as
light pulses, rendering them impervious to EMI and RFI. Glass Fiber-Optic cable comes in 2
forms, Multimode, which has a thicker core and uses LED’s as a lightsource, and Single-mode,
which uses lasers and can transmit signals further. With fiber-optic cable 2 cables are usually
needed as the connectors are half duplex, meaning that information can only flow in one
direction at once.
Bus Topology: A physical topology in which all components are installed along one cable in a line
that goes from one to the next like a bus line through a city. The cable must be terminated to
prevent signals from bouncing back and causing network errors.
Ring Topology: This is a physical topology in which the hosts are connected in a ring or circle. It is
similar to the bus topology accept the first host is connected to the last. A frame called a token
is sent around the ring which stops at each host, which then transfers any information with it’s
address information to the frame. This is then removed when the frame stops at the destination
host.
Star Topology: This is a physical topology with a central device such as a switch or router with
each host directly connected by it’s own cable segment.
Hierarchical Topology: This is also known as the extended star topology and has a central
network device attached to other network devices, then the hosts connected to these. This
topology is usually used by large corporations or universities.
Mesh Topology: This is a physical topology in which all devices are connected to each other. This
is used in WANs that interconnect LANs.
Broadcast Topology: This is a logical topology in which all hosts address data to a specific host or
else to all hosts on the network. There is no order for data transmition, it is a first come first
served system.
Token Passing: This is a logical topology in which a central device such as a router passes a token
sequentially to each host, which is then allowed to send data on the network. If a host has no
data to send it passes the token on to the next host on the network.
Ethernet Architecture: This is a network architecture that uses either a bus or broadcast logical
topology and either a bus or star physical topology, though many newer networks now use the
extended star topology. It is based on the IEEE 802.3 standard which dictates that CSMA/CD is
used as the access control method. Standard speeds are 10 or 100 Mbps, though newer
standards are available that are capable of 1000 Mbps.
IEEE 802.3: This is the standard used by networks with an Ethernet architecture. It means that
CSMA/CD must be used to control network access.
CSMA/CD: Carier Sense Multiple Access with Colision Detection. This is a means of controling
access to the network where each host listens to the network wire until it hears it is clear. This is
similar to listening for a dial tone before dialing a number. The host may only transmit if no
other is doing so. If another host hears the same clear signal and transmits a collision occurs and
one or other of the hosts will pick a random time to try transmitting again.
Token Ring: This is a network architecture that was originally developped by IBM based on the
token passing access control method. It uses a star physical topology, but a ring logical topology,
so is referred to as a star-wired ring. Though the computers are connected in a star topology,
the wiring in the central hub forms a logical ring by sending a token out one port to a host, then
out the next when a host sends it back.
MSAU: Multistation Access Unit. This is the central hub for a token ring network and is generally
used with computers and IBM Mainframes. The wiring inside the device forms a circular data
path, allowing a token to be sent around the network as if it was a ring topology.
FDDI: Fiber Distributed Data Interface. This is a kind of token ring network that is often used to
connect several buildings in an office complex or on a university campus. It combines High speed
and performance with the advantages of the token passing ring topology. It consists of a dual
ring of fiber optic cable. The outer ring is known as the primary ring and the inner as the
secondary ring. Generally only the primary ring is used but the secondary ring is automatically
used if the primary ring fails. This architecture can support up to 500 computers per ring with a
cable length of 100 km. A repeater is required to generate signals every 2 km. Recently these
networks have been largely replaced by faster ethernet networks.
CCITT: Comite Consultatif International Telephonique et Telegraphique. This committee
develops standards for international communication. They developped the standard for sending
faxed documents as well as standards for sending data over telephone lines at up to 56 Kbps.
After 1992 the CCITT became the ITU Telecommunication Standardisation Sector or ITU-T.
ITU: International Telecomunication Union. This is the specialiased agency of the United Nations
that is responsible for information and communication technologies. This organisation
coordinates the shared global use of the radio spectrum and promotes international
cooperation in assigning satelite orbits, as well as working to improve telecommunications
infrastructure in the developping world. It is also responsible for international standards. ITU
also organizes worldwide and regional exhibitions and forums, such as ITU TELECOM WORLD,
bringing together representatives of government and the telecommunications
and ICT industry to exchange ideas, knowledge and technology. The ITU is active in areas
including broadband Internet, latest-generation wireless technologies, aeronautical and
maritime navigation, radio astronomy, satellite-based meteorology, convergence in fixed-mobile
phone, Internet access, data, voice, TV broadcasting, and next-generation networks. ITU was
formed 17 May 1865 and is based in Geneva, Switzerland, and its membership includes 192
Member States and around 700 Sector Members and Associates.
Note: retrieved 9 May 2011 from wikipedia:
http://en.wikipedia.org/wiki/International_Telecommunication_Union
IEEE: Institute of Electrical and Electronics Engineers. This is a non-proffit technical proffessional
organisation founded in 1884 and formed of engineers, scientists, and students. It has more
than 377 thousand members in 150 countries and is a leading authority in technical areas
ranging from computer engineering, to biomedical technology and aerospace. The IEEE has over
860 active standards, but they are best known for developing standards for the computer and
electronics industry. Particularly, the IEEE 802 standards for networking are widely followed.
ISO: International Standards Organisation. This is a non-governmental international organisation
composed of national standards bodies from over 140 countries. It was established to promote
standardisation, and its work results in international agreements that are published as
international standards.
ANSI: American National Standards Institute. This is a private, Non-proffit organisation which
administers and coordinates America’s voluntary standardisation and conformity assessment
system. It identifies needs for national standards in both the business and industrial sectors and
coordinates the development and implementation of these standards, resolving national
standards problems, and ensuring effective participation in international standardisation. ANSI
does not develop standards itself, but rather it promotes agreement and concensus among
qualified groups, resulting on their acrinum being seen on many different standards.
IEC: International Electro-technical Commission. This organisation was founded in 1906 and is
charged with preparing and publishing international standards for all electric, electronic, and
related technologies. The IEC is formed from over 60 countries and aims to promote
international cooperation on questions relating to electrical technologies such as terminology,
symbols, measurement, safety, the environment, and performance. The IEC is recognised by the
World Trade Organisation and is trusted by it to monitor national and regional standards
organisations. Agreeing to use the IEC’s international standards as the basis for national or
regional standards is part of the WTO’s Technical Barriers To Trade Agreement.
IAB: Internet Architecture Board. The Internet Architecture Board (IAB) is the committee
charged with oversight of the technical and engineering development of the Internet by the
Internet Society (ISOC). It oversees a number of Task Forces, of which the most important are
the Internet Engineering Task Force (IETF) and the Internet Research Task Force (IRTF). The body
which eventually became the IAB was created originally by the United States Department of
Defense's Defense Advanced Research Projects Agency with the name Internet Configuration
Control Board during 1979; it eventually became the Internet Advisory Board during September,
1984, and then the Internet Activities Board during May, 1986 (the name was changed, while
keeping the same acronym). It finally became the Internet Architecture Board, under ISOC,
during January, 1992, as part of the Internet's transition from a U.S.-government entity to an
international, public entity.
Note: Retrieved 9 May 2011 from Wikipedia:
http://en.wikipedia.org/wiki/Internet_Architecture_Board
ISOC: Internet Society. This is a Non-Proffit organisation that aims to provide direction in
internet related standards, education, and policy. It provides a corporate structure for the
internet standards development process. This became necessary as many of the main forces of
the internet were very informal organisations from a legal perspective and there was a growing
need for financial support and organisational structure, which is provided by the ISOC.
Note: Retrieved 9 May 2011 from wikipedia: http://en.wikipedia.org/wiki/Internet_Society
IETF: Internet Engineering Task Force. This is a standards organisation which aims to create
standards applying to the internet to improve usability. It is a very informal organisation made
up of a number of working groups with no formal membership or membership requirements.
These groups are formed on specific topics and are expected to disband when they finish the
task they set out to achieve. Unlike its parallel task force, the IRTF, it focuses on short term
issues relating to engineering and standards making, rather than research into the evolution of
the internet. The IETF was formed on January 16 1986.
Note: Retrieved 9 May 2011 from wikipedia:
http://en.wikipedia.org/wiki/Internet_Engineering_Task_Force
IRTF: Internet Research Task Force. This task force is made up of a number of long term research
groups and is responsible for long term research into the evolution of the internet. It works on
topics relating to internet protocols, applications, architecture, and technology, and is made up
of individuals rather than representatives of organisations. The long term nature of the research
groups provides stability and helps maintain research collaberation and teamwork in exploring
research issues.
Note: Retrieved 9 May 2011 from wikipedia:
http://en.wikipedia.org/wiki/Internet_Research_Task_Force
TIA/EIA: Telecommunications Industry Association and Electronics Industries Alliance. These are
2 American trade organisations that jointly develop and publish a series of standards relating to
structured voice and data wiring for LANs. This became necessary after 1984 when the
telephone industry in America was deregulated, transferring responsibility for on premises
cabling to the building owner.
10BASE-T: This is a popular ethernet technology that can transmit at up to 10 Mbps. It uses a
star topology and runs on twisted pair copper cabling with baseband transmition being used,
and a maximum cable length of 100 meters. While cables are inexpensive and easy to install,
they can be effected by EMI.
Baseband Transmition: This is where the entire bandwidth of a cable is used for one kind of
transmition.
100BASE-TX: This is the technology used for fast ethernet, and has a theoretical transmition rate
of 100 Mbps. It has a maximum cable length of 100 meters and uses baseband transmition with
cables being susceptible to EMI.
1000BASE-T: This is a network architecture that supports transfer rates of up to 1 Gbps. It is
commonly known as Gigabit Ethernet and has interoperability with 10BASE-T and 100BASE-TX. It
has a maximum cable length of 100 meters and cables are susceptible to EMI. As well as this
NICs and switches that support it are expensive, and aditional equipment is required.
Wi-Fi: Wireless Fidality. A method of transmitting data via radio waves that means that no cable
is required between the network device and the host. This is controled by the IEEE 802.11 group
of standards which determine the capabilities, speeds, and effective ranges and frequencies of
such networks.
IEEE 802.11a: This is a standard that controls wireless LANs. Devices conforming to this standard
opperate in the 5 GHZ radio frequency range, and have a maximum speed of 54 Mbps with a
maximum range of 45.7 meters or 150 feet.
IEEE 802.11b: This is a standard controling WLANs. Devices conforming to this standard allow
WLANS to reach a theoretical data rate of 11 Mbps over a range of up to 91 meters or 300 feet.
IEEE802.11g: This is a standard controling WLANS. 802.11g devices have a maximum transmition
rate of 540 Mbps. Devices conforming to this standard transmit on the 2.4 GHZ frequency range.
These devices are backward compatible with 802.11B devices and can transmit over the same
range of up to 300 feet.
IEEE 802.11N: This is a newer standard of wireless transmition with a maximum theoretical
bandwidth of 540 Mbps. It opperates in either the 2.4 or the 5 GHZ range and has a maximum
range of 250 meters or 984 feet.
TCP/IP Model: Transmition Control Protocol / Internet Protocol Model. This is an architectural
model that was developed by researchers in the American Department Of Defence as a common
frame of reference for explaining the TCP/IP protocols, the dominant standard for moving data
across networks. It is divided into 4 layers, Application, transport, internet, and network access.
Each of these layers encompasses a number of different protocols that perform specific tasks.
Application protocols provide network services to such things as web browsers and email
clients, and include such things as HTTP, SMTP, and POP3, as well as DNS services.
Transport layer protocols are responsible for end to end management of the data, as well as
dividing it into manageable pieces. These protocols specify which application is requesting data
through specific ports, and include TCP and UDP.
Internet layer protocols provide connectivity between hosts in a network. This is also where IP
addressing and routing take place, and include IP, ICMP, RIP, and ARP, as well as routing
protocols.
Network access layer protocols describe the standards that hosts use to access the physical
media and include such things as the IEEE802.3 technologies as CSMA/CD and 10BASE-T. This is
also where MAC addressing exists.
OSI Model: Open Systems Interconnect Model. This was developped by the International
Standards Organisation in the early 1980’s to standardise the way devices communicated on a
network. Today most network vendors use this framework for their products. The OSI model is
divided into 7 distinct layers, with each layer being responsible for part of the process of
transferring data across a network. Data is said to virtually travel down these layers on the
sending computer, then up the layers of the receiving computer. These layers are application,
presentation, session, transport, network, data link, and physical. Nemonics may help to
remember these layers. 2 of the most common are “all people seem to need data processing”,
and “please do not throw sausage pizza away”.
The application layer of the OSI model is responsible for providing network access to
applications such as email clients and web browsers.
The presentation layer is responsible for changing data formats to provide a standard interface
for the application layer.
The session layer is responsible for establishing, managing, and terminating the connections
between devices so that data may go through.
The transport layer is responsible for providing reliable transport and flow control across the
network. At this point information is consider to be data, and is broken down into more
manageable segments or PDU’s, with information being added to it for reliable transport across
the network. This information includes port numbers, sequence numbers, and
acknowledgement numbers, and is stripped away on it’s way back up to the application layer of
the receiving computer.
The network layer of the OSI model is responsible for routing data and also for logical
addressing. At this point the data segments are broken down into packets that contain IP
address and other layer 3 control information.
The data link layer encapsulates the packet into a frame, with physical addressing and error
correction information that is ready to be transported across the network.
The physical layer describes the physical media, cables and wiring, as well as all physical and
electrical specifications of network devices that the frame travels through as a series of bits,
before being reassembled by the receiving computer.
PDU, Transport Layer Protocol Data Unit. This describes a segment of information as it passes
through the transport layer of the OSI model. Here the information is given such information as
port numbers, as well as other information to help with orderly transport across the network.
DUN, Dialup Networking. This is where computers use modems to communicate across the
public telephone network.
PPP connection: Point to point protocol connection. The way in which computers communicate
over telephone lines.
ISDN: Integrated Services Digital Network. This is a kind of network connection that uses the
analog telephones wires to send data, but uses digital technology to carry the data, making it
faster, and allowing for higher quality of voice transmitions. It uses 2 different kinds of
communication channels, the B channel for voice or data, and the D channel, usually for
signalling though it can be used for data. These digital connections come in 3 types, BRI, PRI, and
BISDN.
BRI ISDN: Basic Rate Interface Integrated Services Digital Network. This is an ISDN connection
that offers a 128 kbps connection using 2 64 kbps B channels. It also uses 1 16 kbps D channel
for call setup, control, and teardown.
PRI ISDN: Primary Rate Interface Integrated Services Digital Network. This is a kind of ISDN
connection which offers up to 1.544 mbps over 23 B channels in North America and Japan or up
to 2048 kbps over 30 B channels in Europe and Australia. 1 64 kbps D channel is also used for
call maintenance.
BISDN: Broadband ISDN. This is a type of ISDN connection usually only used in network
backbones, and manages several different types of service at the same time.
DSL: Digital Subscriber Line. This is the most common connection used by home users today and
comes in various forms that run at different speeds. With a DSL connection a digital signal
shares the phone lines with their normal analog signals allowing for very fast communication
between users and phone companies. Also, one does not have to dial the ISP to use the internet,
and as the internet is always on, one can use the phone at the same time.
ADSL: Asymmetric Digital Subscriber Line. This is the most common technology for DSL internet
connections and has different bandwidth capabilities in each direction. It has a fast download
speed, typically 1.5 mbps, though speeds can range from 384 kbps to over 6 mbps, with a much
slower upload speed.
HDSL: High Data Rate Digital Subscriber Line. This is an implementation of DSL connections
which offer equal bandwidth in both directions, typically 1.544 mbps in America and 2.048 mbps
in Europe.
SDSL: Symmetric Digital Subscriber Line. This is an implementation of DSL that offers the same
speed, up to 3 mbps, for both uploads and downloads.
VDSL: Very High Data Rate Digital Subscrieber Line. This is a DSL technology that offers bery high
bandwidth in both directions, though it is asymmetrical. It offers anywhere from 13 to 52 mbps
downstream, and up to 16 mbps upstream.
IDSL or ISDN DSL. Integrated Services Digital Network Digital Subscriber Line. This is a DSL
connection that is run over ISDN lines. It is a set of CCIT/TU standards for digital transmition
over ordinary telephone copper wire, as well as other media, at up to 144 kbps. This
implementation is generally used in areas that don’t qualify for other forms of DSL. This kind of
connection requires an ISDN adaptor in place of the modem both at the ISP and User side.
PLC: Power Line Communication. This is also known as Power Line Networking (PLN), Mains
Communication, and Power Line Telecoms (PLT). This is a method whereby an analog signal is
imposed over the standard 50 or 60 HZ alternating current that travels in power lines. This signal
can carry voice and data signals. Power Line communication may be available where other high
speed connections are not, and has the advantage that a connection can be made wherever
there is a power outlet.
WPAN: Wireless Personal Area Network. This is a term that describes a small wireless network
that may not connect to the internet. An example of this would be a network formed of
bluetooth devices.
Bluetooth: This is a wireless technology that allows devices to connect over short distances. 1
bluetooth device can connect up to 7 other bluetooth devices. This technology is often used
with PDAs and smartphones, and is described in the IEEE 802.15.1 standard. Bluetooth
opperates in the 2.4 to 2.485 GHZ radio frequency band and incorporates AFH, with class 1
having a range of up to 100 meters, class 2 having a range of up to 33 meters, and class 3 having
a range of up to 1 meter. Speeds can be up to 1.2 mbps for version 1.2 or 3 mbps for version 2.
IEEE 802.15.1: The IEEE standard that describes the capabilities and technical specifications of
bluetooth.
AFH: Adaptive Frequency Hopping. This is a feature of some radio wireless technologies,
particularly bluetooth, which allows the device to change frequencies within it’s assigned band,
cutting down on the chance of interference if other similar devices are present.
VoIP: Voice Over Internet Protocol. This is a method of carrying telephone calls over the
internet. This often relies on an internet connection which can be a disadvantage if the internet
connection is interupted. It works by converting the analog signals of our voices into digital
information that can be transported in IP packets.
PSTN: Public Switch Telephone Network. This is the standard telephone network through which
ordinary phone calls are usually made.
VPN: Virtual Private Network. This is a private network that uses a public network such as the
internet to connect remote users together. A VPN uses dedicated secure connections routed
through the internet to connect a company’s private network to a remote user. This means that
a worker can connect to a company private network from home and they become part of that
network and have access to all the company resources just as if they were connected to the
LAN.