Glossary of Terms

Access Terms

Access Card
A coded employee card, usually the size of a credit card, recognizable to the access control system and read by a reader to allow access. It can be use for photo indication of the cardholder and for other data collection purposes. Card technologies include magnetic strips, wiegand-effect, proximity (active/passive), barium ferrite, and smart/intelligent cards.
Active Card
An access control pron/ximity card, which is powered by a batteries have limited life span and in most cases cannot be replaced- hence the customer within the life expectancy of the system.
Access Code
Any system or method which controls the passage of people and/or vehicles into or out of a secure area or structure by means of a numeric or alphanumeric keypad.
Access Control
A general term describing the control, management, and monitoring of the entrance and exit of people through secure areas.
Access Control System
A system that provides access to authorized persons, and may also record and report (1) which persons entered or left the facility or areas within facility, (2) which doors or areas were accessed while within the facility, and (3) the time that each event occurred. A facility control system may also include access control equipment such as keys, access cards, locks, card reader, biometric identification devices, recorders, printers, and control equipment. Identifying, logging, and supervising persons who arm and disarm a burglar alarm system (commonly referred to as opening and closing) are also Facility Control System functions.
Access Group
Permission programmed into the access control system to allow a cardholder to enter certain doors at specified times.
Access Level
A security rating that must be met before access to a secure area is granted.
Access Point
Each means of entry into a controlled security area, consisting of a card reader, monitor switches and/or latches. Access points are wired to an access control panel.
Access Relay
An electrically operated switch that is activated when access is granted to unlock a door.
Access Request
The act of presenting the information necessary to verify a person’s identity.
Asser Tagging
Usually managed by active tags and long-range readers/door loops. Asser tagging provides tags, which are suitable for fixing to items such as laptops, projectors etc. Tags can be static (for fixed location items-works of features such as temper, so that the tag cannot be removed whist within the secure area before the item is taken off site.
Access Time
The period of time during which an access point is unlocked. (Also see shunt time)
Anti Pass back
-or- Anti-Tailgating. This feature protects against more than one person using the same card or number. It defines each system card reader and card I.D. number as in, out, or other. Once a card is granted access to an IN reader, it must be presented to an out reader before another in reader access is granted. Cards will continue to have access to all authorized other readers.
Audit Trail
A sequential record that accounts for all the activities of an access control system. This record allows for the analysis of events over a given time period.
The determination whether or not a given individual should be granted a requested form of access to a specific network object.
Authorized Person
A person who has been cleared to enter a secure area.
-or- American Wire Gauge. A wire diameter specification based on the American standard. The smaller the AWG number, the larger the wire diameter. Alternatively: - the measure of the diameter of a conductor. AWG is the U.S. standard measuring gauge for certain conductors, including copper. The higher the AWG number the thinner the wire. This measure stems from the fact that the original measurement represented the number of times the wire was run through a wire machine, which thus reduced the diameter of the wire. Thus a 24.guage wire was thinner than an 18-guage wire because it was run through a wire, reducing the overall diameter.
To use a card with a reader to gain access to protected areas; a card itself, especially one with a photo I.D.
Badging Software
Security software that is capable of creating photo identification badges.
Low and low security means of providing access control. Commonly seen in libraries. Two methods of barcode are available – open (as seen in library books) which can be copied and reproduced giving no security at all and Obscure, which has a panel over the barcode stopping copying.
Refers to readers that identify human attributes such as fingerprint, hand geometry, and voice recognition or iris analysis.
Biometric Data
The information extracted from the biometric sample and used either to build a reference template (template data) or to compare against a previously created reference template (comparison data).
Biometric Device
The part of a biometric system containing the sensor that captures a biometric sample from an individual.
Biometric Identification
A method using a person’s physical or chemical attributes for identification to the alarm system or the monitoring facility.
A plastic card containing user ID information. Cards come in many different technologies including proximity, wiegand, magnetic stripe, bar code, & smart. The card is inserted into, swiped through, or presented to the card reader.
Card Number
This is the internal encoded number- as read by the system.
Cashless Vending
A third party supplied system that allows the employee to use their access control card to purchase lunch, coffee etc. Smart cards are now being promoted for this purpose. Older systems use track 3 of the magstrip – only high output mag – strip tape is accepted by some suppliers of cashless vending i.e. Girovend.
Clock & Data
A card format usually associated with magstrip. This can however be reproduced by proximity and other reader types.
COM Port
A hardware device that allows a computer to communicate with external devices.
Control Point
An exit or entry point such as a door, turnstile, or gate, where access is controlled.
A microprocessor based circuit board that manages access to a secure area. The controller receives information that it uses to determine through which doors and at what times cardholders are granted access to secure areas. Based on that information. The controller can lock/unlock doors, sound alarms, and communicate status to a host computer.
This is the term for resilience of a mags trip. Standard access control cards are Hi Co whist Bankcards are usually Lo Co.
Default Degraded Mode
A mode of controller operation that provides a minimal authorization level in the event of controller failure.
Device Address
Value set on an access control device to determine its unique identity.
Turned off. Not active.
A generic term for a securable entryway. In many access control applications a "doors" may actually be a gate, turnstile, elevator door, or similar device.
Door Ajar
A condition that occurs when a door is left open after a valid user has passed through.
Door Closer
A device or mechanism to control the closing of a swing door.
Door forced Alarm
An alarm generated when a door is forced open, opening the door switch contact.
Hardware device used to activate software only while present stops software theft.
Door Held Open
Alarm generated when an access-controlled door is wedged in the open position after being opened by authorised means. Doors must be fitted with a door contact. Some systems offer local alarm feature prior to a full alarm at a central location.
Door Loop
-or- reader. This is a cable placed around the doorframe, within the floor or ceiling to create a larger aerial for a proximity reader. Uses for Hands free access and/or asset tagging.
Door Open Time
The time allowed for a controlled door to remain open after a valid entry. At the expiration of this time, the system records a transaction, which may be defined as an alarm. If the alarm bypass relay is used, it would also de-energize at the end of this time.
Door Schedule
The listing of all door openings on the project by architect’s mark including a description of each door opening. The schedule is normally found in the contract plans or in the specification portion of the contract documents.
Sending information from a host computer to a peripheral device in a access control system.
Forcing a person to provide access to a secure area against that person’s wishes.
Duress Alarm
A device that generates a silent alarm signal in the event a person is experiencing duress. This device may be a stand-alone signalling device or it may be incorporated into a reader.
Duress Code
An alphanumeric code which, when entered into an access control system, alerts the system to a duress condition.
Exit, depart, leave (opposite of ingress).
Electric Strike
A strike designed to be remotely controlled to permit the door to be opened without retracting the latch or bolt.
Pertaining to combined electric & magnetic fields associated with movements of electrons through conductors.
Electromagnetic Interference EMI
Excess electromagnetic energy radiated by an electrical device that may affect the operation of other electrical devices.
Electromagnetic Lock
An electric door lock that uses an electromagnet to hold a door closed.
The rearrangement of the bit stream of a previously digitally signal in a systematic fashion to make the information unrecognizable until restored on receipt of the necessary authorization key. This technique is used for securing information transmitted over a communication channel with the intent of excluding all other than authorized receivers from interpreting the message. Can be used for voice, video and other communications signals.
The process of collecting biometric samples from a person and the subsequent preparation and storage of biometric reference templates representing that person’s identity.
Enrolment Time
The time period a person must spend to have his/her biometric reference template successfully created.
An IEEE standard (IEEE-8020) for computer data communications. A local area network used for connecting computers, printers, workstations, terminals, etc. within the same building. Ethernet operates over twisted wire, coaxial cable, and RF at speeds up to 1000 Mbps.
Ethernet Hub
A networking device that enables attached devices to receiver all the information transmitted over the network, and to share network bandwidth.
Event Log
A record of actions performed and recorded by a security or access control program.
Exit Alarm
A device that indicates (either audibly or silently) that a secure door has been forced opened.
Exit Delay Timer
An electronic timer that delays a person from immediate exiting a building for a pre-programmed amount time (usually 15 or 30 seconds). It is used primarily for loss prevention or wandering patient systems.
Facility Code
When access control was originally developed, the memory capacity of chips was relatively small. If the access control systems would ever lose power, the system needed a "default mode or degraded mode". A system would go into a default mode when power was lost. In a default mode the system would fall back to the facility code to let someone enter the facility. Rather than look at each individual number, the system would look for any card that had the correct facility code. This meant that if two systems were installed across, the street from each other, the system on one side of the street might have facility code 12, for example, and the company on the other side of the street would have code 13. Cardholders who had facility code 12 could not enter a building with a facility code 13, and vice versa. Although memory in chips has greatly increased, and the systems really no longer require a facility code, the access control industry still often uses a facility code in their formats as a convenient way to partition card data.
Fail Safe
A device that requires power (electrical energy) to remain locked. This is also referred to as fail unlocked.
Fail Secure
A device that requires power (electrical energy) to remain locked. This is also referred to as fail unlocked.
False Acceptance
When a biometric system incorrectly identifies an individual or incorrectly verifies an impostor against a claimed identify.
False Acceptance Rate/FAR
The probability that a biometric system will incorrectly identify an individual or will fail to reject an impostor. The rate given normally assumes passive imposter attempts.
False Rejection
When a biometric system fails to identify an enrolee or fails to verify the legitimate claimed identity of an enrolee.
False Rejection Rate/FRR
The probability that a biometric system will fail to identify an enrolee, or verify the legitimate claimed identify of an enrolee.
Fingerprint Reader
A biometric reader that identifies a person based on the person’s fingerprint pattern.
The structure of the data stored in an access control card. Most access control system OEMs use their own unique formats.
The size of a wire in diameter with higher gauges being smaller, and lower gauges being larger.
Global Unlock
A normally-open input that, when closed, generates a signal that unlocks all doors in the access control system.
Available on SGA. Customers site drawing are either produced or taken from CAD file. SGA uses bitmap files for Graphic maps – which can be site photos etc. Icons can then be added for monitored/controlled points, which are animated to show their status.
Guard Tour
A defined route of a security guard.
-or- Graphical User Interface. Technique used to display information on a television screen or other display device in order to make the operation of some equipment easier or provide enhanced functions.
Hand Geometry
A biometric access control technology that verifies a person’s identify by using the variations in hand size, finger length, and finger thickness.
Hall Effect
Monitoring built in some magnetic locks to ensure that the holding force is up to the specified levels. Provides monitoring to overcome the typical methods of reducing holding force-grease, film etc - making forced entry much easier.
Free the use of long-range readers/Door loops with advice tags to monitor the movement of personnel and assets.
Co Type of magnetic stripe tape – see Coercivity
The one-to-many process of comparing a submitted biometric sample against all of the biometric reference templates on file determine whether it matches any of the templates and, if so, the identity of the enrolee whose template was matched. The biometric system using the one-to-many approach is seeking to find an identity amongst a database rather than verify a claimed identity.
Identification Card
A card that stores the information necessary to verify the identity of the cardholder.
Iris Recognition
A physical biometric that analyses iris features, found in the colored ring of tissue that surrounds the pupil.
ISO Cards
A card, which meets the dimension requirements for credit cards. Used for Proximity technologies.
A patch cable or wire used to establish a circuit, often temporarily, for testing or diagnostics.
Proximity tag supplied in a form that can be put on to a key ring
An alphanumeric gird, which allows a user to enter an identification code.
Key Tag
An access control identification device assigned to an individual to give that individual access rights to an access control system. Typically, the tag is attached to a key ring or similar device to provide quick, convenient access to the tag. Each tag has a unique identification code. That identification code is used by a controller to determine through which doors and at what times of day cardholders are granted access to a secure area.
Kilobits Per Second
A measure of the speed that data can travel. Measured in thousands of bits per second. This is the unit commonly used when determining network connection speed.
Lan Local Area Network
An IT data communication network for a local geographical area. This may be within one building or a cluster or buildings on a site/campus.
Liquid Crystal Display. A screen for displaying text/graphics based on a technology called liquid crystal, where minute currents change the transparency of the by changing the polarization angle. The advantages of LCD screens are very small power consumption (can be easily be easily battery driven) and low price of mass-produced units. The disadvantages are narrow viewing angle, slow response, and invisibility in the dark unless the display is back lighted, and difficulties displaying true colors with color LCD displays.
Light emitting Diode. A semiconductor diode, which produces light when a certain low voltage, forward bias, is applied to it. Like a normal diode it conducts only in one direction.
Magnetic Lock
A door lock made up of an electromagnet and a strike plate. The electromagnet is mounted in the doorframe, the strike plate in the door. When power is applied to the electromagnet, the strength of the electromagnet keeps the door locked.
Magnetic Stripe Card
An access control card with a strip of recordable magnetic material, on which data is encoded.
Magnetic Stripe Reader
A reader capable of reading and interpreting cards using magnetic stripes to encode data.
Smart card chip, which can be used for access control. Each chip has a unique number, which can be read by an access control system – or a sector of memory within the chip can be programmed with an access control number for use by the system.
Access control door or lock that has a contact fitted to it to show its position/status. Contact can be either magnetic or built in to the lock/release – separate magnetic contact is preferred.
Contact form of access control – the magstrip is run past read heads within the reader. Low to medium security as the cards can be duplicated.
A device used to convert data (usually RS232) on into an analogue format for transmission over telephone lines – and then converts back again. One Modem required at each end of line.
A series of controllers, all connected via a communications cable. A group of computers, all connected via a communications cable.
Normally Closed
The state of an input device that continually keeps a circuit closed or complete until forced by an action or event to open that circuit.
Normally Open
The state of an input device that continually keeps a circuit open or incomplete until forced by an action or event to close that circuit.
Original Equipment Manufacturer.
A finger image captures technique that uses a light source, a prism and a platen to capture finger images.
Passive Card
A proximity device which is powered one the card/tag enters the proximity reader field. There is no on-board battery- therefore read rangers are reduces BUT there is no battery to replace.
Photo ID
Adding a photograph and printing other details on to an ISO card. This can include customer’s company logo etc.
Personal Identification Number. Used with keypads – should be considered for use in addition to any reader technology at the perimeter of a site to reduced the risk of lost cards being found and used by unauthorised person(s).
Passive Infra Red. A technology, which uses the bodies, heat to detect presence and then generate a signal. Can be used for hands free control. Note any heat can detected by a PIR.
Protocol Convector
A device used to change data formats- from a PCs serial port (RS232) to that required by the controller communications port.
Peer to Peer
A simple kind of network that sets up a conversation between two machines without a middleman. Both carry out the same functions.
Personal Identification Number PIN
A series of numbers and/or numbers and/or letters associated with a particular individual as means of identification.
More than one individual entering a secure area using one access card. Following an authorized person into a secure area. Also know as tailgating.
Programmable Card
A card in which data may be encoded.
A type of card technology that sends wireless digital data from a card to a reader through means of an electrostatic coupling.
Proximity Card
A card using proximity technology to store and transmit encoded data.
Proximity Reader
A reader capable of reading and interpreting cards using radio frequency identification to encode data.
Power Supply
Component of all electronic devices used to transform the electrical power supplied through a wall outlet into power the electric component can use.
Radio Frequency Identification
A method of reading a card using radio frequency energy to transmit information from the card to a reader.
Relay Output
A relay on the controller that changes its state upon command by the controller. Often the alarm relay output activates an audible alarm used to annunciate a door alarm.
Electricity operated keeps for either a mortise or latch lock.
Rim Release
Surface mounted door release used with rim locks.
Long Range comms protocol requires two pairs – transmit & receive. This format extends the communications line up to approx. 1,200m.
Request to Exit. Push button or PIR device that releases the door.
Request to Exit
-or- REX. The activity of having a remote device (such as a push button) tell the access control system to release the door so someone can exit.
A format of digital communication using a three wire unbalanced presentation. The RS-232 standard defines the presentation and voltages for asynchronous communications, but it does not define how the data should be represented by the bits, i.e., it does not define the overall message format and protocol. It is very often used in computers, CCTV and communications between keyboards and matrix switchers.
This is an advanced format of digital communications compared to RS-232. It is a balanced line transmission system. The major improvement over RS422 is in the number of receivers that can be driven with this format, up to 32. It is classically a half duplex 2-wire presentation.
Serial Interface
A digital communications interface in which data are transmitted and received sequentially along a single wire or pair of wires. Common serial interface standards are RS-232 and RS -422.
Serial Port
A computer I/O (input/output) port through which the computer communicates with the external world. The standard serial port is RS-232 based and allows bi-directional communication on a 3-wire connection, as a serial data stream.
Shear Lock
A magnetic lock that is fitted into the transform of the door closing or critical. When locked the lock has shear pins, which fit into that armature to increase the holding force.
Site Code
Part of the card number, which can be specific to that site or customers.
Smart Card
An identification card or access control card with a built-in integrated circuit chip. This gives the card microprocessor memory and intelligence to use for storing data.
An access control system that makes its own access decisions without communicating with a central controller.
Time & attendance. Record employees’ on/off site time and can link to payroll systems. Should be kept separate from the access control system – card compatibility only is the best solution.
A proximity access control device – usually or the "clamshell" type – not a card or key fob.
Track 2
Standard magship cards have three tracks – 1, 2 & 3. Track 2 is the most commonly track used for access control. Track 3 is the approved track for "read /write"- used for cash less vending etc.
More than one individual entering a secure area using one access card. Following an authorized person into a secure area. Also know as piggybacking.
-or- Transmission Control Protocol / Internet Protocol. The Internet protocol suite can be described by analogy with the OSI model, which describes the layers of a protocol stack, not all of which correspond well with Internet practice. In a protocol stack, each layer solves a set of problems involving the transmission of data, and provides a well- defined service to the higher layers. Higher layers are logically closer to the user and deal with more abstract data, relying on lower layers to translate data into forms that can eventually be physically manipulated.
Time Zone
A specified period of time in which access is allowed. A variety of time zones may be idefined to accommodate the access needs of a variety of people.
Twisted Pair
A cable composed of two small substantially insulated conductors, twisted together with or without a common covering.
The UL label on a product signifies that the product has met the Underwriters Laboratories requirements and that the product manufacturer is authorized to use the UL symbol on their products.
-or- Universal Serial Bus. A 1-5M/sec (12 Mbit/sec) serial communication interface than can support 127 separate devices consisting of 4 wires; power, ground, data in and data out.
Wiegand Card
A plastic card, approximately the shape of a credit card, which has an embedded module of inert, specially treated ferromagnetic wires, which generate a voltage pulse that can be sensed by a coil within the card reader.
Wiegand Reader
A reader capable of reading the information encoded on a wiegand card.

Fire Terms

Addressable Device
A fire alarm system component with discreet identification that can have is status individually identified, or that is used to individually control other functions.
Air Sampling-Type Detector
A detector that consists of piping or tubing distribution network from the detector to the areas being protected. A fan in a detector housing draws air from the protected area back to the detector. The air is analysed for products of combustion.
Alarm Signal
A signal indicating an emergency requiring immediate action, such as a fire alarm signal.
Alarm Verification
A feature of some automatic fire detection and alarm systems to reduce unwanted alarms. Smoke detectors must report alarm conditions for a minimum periods of time, or confirm alarm conditions within a given time period after being reset, to be accepted as a valid alarm indicating signal.
Analog Device/Sensor
An initiating device that transmits a signal indicating varying degrees of condition, such as smoke obscuration level. As contrasted with a conventional sensor which can only indicate an on / off condition.
A unit containing two or more indicator lamps, alphanumeric display, or other equivalent means in which each indication provides status information about a circuit, condition, or location.
Automatic Fire Detectors
A device designed to detect the presence of fire or products of combustion. Including, but not limited to, heat detectors, smoke detectors, beam detectors.
Manual Call Point
A fire alarm device in which it is necessary to break a specie=al frangible element in order to operate an alarm.
A connector module or interface for power distribution to and among appliances for a rigid conductor in an electric circuit used to connect three or more circuits.
-or- Computer Aided Design. Using computer software to draft or model an object or building for manufacturing or construction.
Central Station Fire Alarm System
A system or group of systems in which the operations of circuits devices are transmitted automatically to, recorded in, maintained by, and supervised from a central station.
Control panel
An electrical device, which switches, buttons, lights, or displays, used to monitor and control other devices or equipment.
-or- Decibel. Logarithmic scale measuring the intensity of sounds 9 the sound pressure level); a 10-decibel (dB) increase represents in a doubling of sound level.
The visual representation of output data other than the printed copy.
End of line device
A device such as a resistor or diode placed at the end of a class B circuit to maintain supervision.
End of Line Relay
A device used to supervise power (usually for 4 wire smoke detectors) and installed within or near the last device on an initiating circuit.
Erasable and Programmable Read Only Memory. An electronic chip used in many different security products that stores software instructions for performing various operations.
The withdrawal of occupants from a building.
Evacuation Signal
Distinctive signal intended to be recognized by the occupants as requiring evacuation of the premises – Normally T3 pattern as per ISO8201.
Exit Plan
Plan for the emergency evacuation of the premises.
Fire Alarm
A system that detects and reports a fire in the protected premises, detects and reports water flowing in a sprinkler system, or detects and reports dangerous conditions such as smoke or overheated materials that may combust spontaneously.
Fire Alarm Control Panel
A system component that receives inputs from automatic and manual fire alarm devices and may supply power to detection devices and transponders or off premise transmitters. The control unit may also provide transfer of power to the notification appliances and transfer condition unit. The fire alarm control panel can be a local unit or a master control unit.
Fire Rating
The classification indicating in time (hours), the ability of a structure or component to withstand fire conditions.
Fixed Temperature Sensor
A heat sensor that is triggered when a predetermined temperature has been reached at the sensor.
Flame Detector
A sensor that sees the infrared, ultraviolet, or visible radiation, caused by a fire.
Four Wire Smoke Detector
A smoke detector which initiates an alarm condition on two separate wires apart from the two wires that are for power.
Gate Valve
A sprinkler valve that opens by lifting a round or rectangular gate out of the path of the fluid. Gate valves are sometimes used for regulating flow, but many are not suited for that purpose, having been designed to be fully opened or closed. When fully open, the typical gate valve has no obstruction in the flow path, resulting in very low friction loss.
-or- Ground. An electrical connection to the earth generally though a ground rod. Also a common return to a point of zero potential, such as metal chassis in radio equipment. Power systems grounding is that point where the neutral conductor, safety ground, and building ground are connected.
Ground Fault
An undesired circuit between shielded pairs of a multiple pair created by random contact between shields. An undesirable circuit condition where interference is created by ground currents when grounds are connected at more then one point.
Ground Floop
A completed circuit between shielded pairs of a multiple pair created by random contact between shields. An undesirable circuit condition where interference is created by ground currents when grounds are connected at more then one point.
-or- Graphical User Interface. Technique used to display information on a television screen or other display device in order to make the operation of some equipment easier or provide enhanced functions.
Heat Detector
A device that detects abnormally high temperature or a rate of temperature increase.
Heating, Ventilation, Air Conditioning (HVAC) Alarm
A system that reports heating, ventilation, and air conditioning system problems, rather than life-threatening emergencies. Public are not normally contacted when theses alarm systems detect a problem; protected property maintenance personnel tend to be notified by the monitoring facility.
High Temperature Sensor
A sensor that detects a higher-than expected temperature-often in an unattended industrial process system.
High Water Level Sensor
A sensor that detects higher-than expected water or other liquid levels. Examples: Rising ground water in the basement of a building.
Initiating Device
Any device that feeds information from the field to the control panel. Examples include smoke detectors, heat detectors, MCPs, etc.
Ionization Smoke Detector
A smoke detector that has a small amount of radioactive material which ionizes the air in the sensing chamber, thus rendering it conductive and permitting a current to flow between two charged electrodes. This gives the sensing chamber an effective electrical conductance. When smoke particles enter the sensing chamber they decrease the conductance of the air by attaching themselves to the ions, causing a reduction in mobility. When the conductance is reduced to less than a predetermined level, the detector responds.
Liquid Crystal Display. A screen for displaying text/graphics based on technology called liquid crystal, where minute currents change the transparency oh the by changing the polarization angle. The advantages of LCD screens are very small power consumption (can be easily battery driven) and low price of mass-produced units. The disadvantages are narrow viewing angle, slow response, and invisibility in the dark unless the display is back lighted, and difficulties displaying true colors with color LCD displays.
Light Emitting Diode. A semiconductor diode, which produces light when a certain low voltage, forward bias, is applied to it. Like a normal diode it conducts only in one direction.
Level Ceilings
Those action of light being reflected and/ or refracted off particles of combustion for detection by a photoelectric smoke detector.
Light Scattering
The action oh light being reflected and/or refracted off particles of combustion for detection by a photoelectric smoke detector.
Line Type Detector
A device in which detection is continuous along a path. Examples include beam smoke detectors and heat sensitive cable.
Equipment or material included in a list published by an organization acceptable to the authority having jurisdiction and concerned with product evaluation, that maintains periodic inspection of production of listed equipment or materials and whose listing states either that the equipment or material meets standards or has been testes and found suitable for use in a specific manner.
-or- Low Voltage. An electrical circuit that carries voltage not exceeding 1,000 volts AC or 1,500 volts DC.
Low Water Sensor
A sensor that detects lower-than expected water or other liquid Levels. Examples: A sprinkler system tank, a building heating system’s boiler, a sprinkler system water reservoir, etc.
Multiple Sensor Alarm
An alarm generated when at least two separate sensors detect the condition before the alarm is triggered. In some instances redundant sensors in different system zones must trip before the alarm is triggered. However, activation of one sensor may trigger an alarm. When this happens, there is a high probability that a real emergency exists.
Standards Australia
Administers the development of and publishes codes, standards, and other material concerning all phases of fire safety.
Non-restorable Initiating Device
A device whose sensing element is designed to be destroyed in the process of operation.
Alarm Device
A fire alarm system component such as a bell, horn, speaker, strobe, etc that provides an audible or visible output or both.
Open Circuit
A circuit is not complete or the cable/fiber are broken. Sometimes called a fault.
Open-Pipe (Deluge) Flow Sensor
A sensor that detects the flow of water in an open-pipe sprinkler system.
Output Device
Any device that feeds information from the control panel to the field for notification. Examples include horns, sirens, strobes, etc.
Particles of Combustion
Substances resulting from the chemical process of a fire.
Photoelectric Smoke Detector
A smoke sensor that detects light reflected off smoke particles in a tiny chamber within the sensor.
Photoelectric beam Detector
A smoke sensor that detects the loss of light between a transmitting unit and an accompanying receiving unit, due to the presence of visible smoke between the units.
Preventive Maintenance
Routine scheduled service work on an alarm system to detect and prevent predictable problems from occurring, such as batteries that lose their ability to retain a charge, smoke detectors that become dirty or blocked, motion detectors whose sensitivity may change with time, switches that may become loose, etc.
Rate of Rising Sensor
A heat sensor that will respond when the temperature rises at a rate exceeding a predetermined amount, which is usually about 15 degrees in 60 seconds or exceeds its threshold of either 135 degrees or 190 degrees.
Restorable Initiating Device
A device whose sensing element is not ordinarily destroyed in the process of operation. This restoration may be manual or automatic.
A special telephone jack used to allow equipment (typically security systems) to seize immediate control of the phone line even if that phone line was in use.
A device designated to produce a signal or other indication in response to an event or stimulus within its detection areas.
Smoke Detector
A sensor device used to reproduce sound waves when a power signal is applied representing those sound waves by vibrating some material that in turn creates vibrations in the air thus generating sound.
Mechanical device used to reproduce sound waves when a power signal is applied representing those sound waves by vibrating some material that in turn creates vibrations in the air thus generating sound.
Point Type Detector
A device whose detecting element is concentrated at a particular location. Examples will include both smoke and heat detectors.
Sprinkler Control Valve Switches
A switch that detects the off-normal position of a shut-off control valve in a sprinkler system to warn of a potentially dangerous situation in which water cannot flow through the pipes in case of fire. Three common types of switches are gate valve, OS & Y, & Post indicator valve.
Sprinkler System Water Flow Sensors
A sensor that detects the flows of water in a sprinkler system.
Supervisory Alarm
Sensors that detect conditions which represent potential problems, and which require attention without unnecessary delay in order to prevent a possible emergency from developing.
An oversupply of voltage from the power company that can last up to several seconds. Power surges are the most common cause of loss to computers and electronic equipment.
To connect a wire conductor to something, typically a piece of equipment.
Twisted Wire, Heat Sensor
A length of twisted steel wire, separated by thermoplastic insulation designed to melt at temperatures indicative of fire. As the plastic insulation melts, the pressure of the twisted steel wires causes the wires to short, triggering the fire alarm signal.
Two-wire Smoke Detector
A smoke detector that initiates an alarm condition on the same pair of wires that supply power to the detector.

IP Networking Terms

An Ethernet standard topology for twisted-pair cabling. The data transfer rate 10 Mbps over a distance of 100 meters (330 feet).
Produces 100 Mbps throughput over twisted pair cabling, usually Fast Ethernet. 100Base-T is built on the older Ethernet standards.
Produces 100 Mbps throughput over twisted pair wiring but uses four pairs of the wiring. Thus making the network a lower quality than 100Base-TX, which uses only two of the pairs of the wiring.
Produces 100 Mbps throughput over twisted pair wiring, usually Fast Ethernet. 100Base-TX is built on newer Ethernet standards, which means it is faster technology than 100Base-T.
The IEEE 802 standards are set for networking. Specifically LANs. Some standards identify wireless, others Ethernet, and so on.
Produces speeds of 1000 Mbps over twisted-pair wiring. Also called Gigabit Ethernet, this technology is normally used in corporations and businesses as a backbone (or foundation) or their networks.
Also known as FireWire, this is a technology that has a bandwidth of up to 1000Mbps. The bus is also hot swappable.
Accelerator Card
An adapter used in a computer to speed up graphics. An accelerator card is type of vide card.
Access Point
A wireless-based device used to connect roaming wireless PC cards to a server. The Internet, or another wireless station. The access point provides mobility from a stationary connection.
Can be an e-mail specification of a person, a specification for a web page or number that identifies a computer on a network.
-or- Asymmetric Digital Subscriber. A type of DSL lines that provides access paths for 6 Mbps in one direction and around 640 Kbps in both directions simultaneously.
-or- Accelerated Graphics Port. A new technology built for the demands of 3D graphical software.
A name given to a computer or person to replace long names or to keep your own name private. Used in chat rooms and computer gaming.
Anonymous FTP
A method of transferring files between two Internet (file Transfer Protocol) sites. FTP is a method of logging on to another Internet site for the main purpose of retrieving or sending files. When a user logs on to the FTP server, he or she can use the Anonymous account (which is like a guest account), meaning anyone can access those files.
Antivirus Software
A program that detects and removes viruses from your computer. These program search for suspicious activities on the system or characteristic patterns. Some antivirus programs compete with computer with computer devices, hardware, and programs for network resources.
-or- Application program interface. A set of interface functions available for applications. API enables the Windows operating system to work with various programs.
Application Layer
One of the ISO/OSI layers. The application layer defines how the applications interact with the network.
ARP(Address Resolution Protocol)
One of the TCP/Ip protocols. ARP translates 32-bit IP addresses into physical network addresses, such as 48-bit Ethernet addresses.
A measurement of the amount of information or data that can pass through any given point on the network: cabling, server, network cards, and so on. The wider the bandwidth, the more data can pass through. With an Ethernet network, bandwidth is measured in megabits per second.
Basic Rate Interface
See BRI.
-or- Basic input/output system. A set of routines that work with the hardware to support the transfer of data through components of the systems, such as memory, hard disks, or the monitor.
The basic unit of information in the binary numbering system, represented by either 0 (for off) or 1 (for on). Computers read binary numbers, or strings of 0s and 1s.
Bit Rate
The rate of data throughput for the medium (modern or other serial device), measured in bits per second.
A wireless connection that works on short-range radio chip, placed in the computer’s disk drive. You use a boot disk to diagnose system problems or to access a system when the computer cannot boot on its own. See also system disk.
Boot Sector
The set of instructions your computer reads when it starts up.
BRI Sector
The set of instructions your computer reads when it starts up.
-or- Basic Rate Interface. BRI lines are a type of ISDN that enables a download speed of 64 Kbps.
A network device that provides a communications path between two network segments to form one logical network. Generally, a bridge is used in larger or corporate networks.
Also called wideband transmission, broadband refers to networking that provides multiple channels of data over a single wire; cable and DSL are two examples.
On a network, a message that is sent to everyone in the area. A server might send a broadcast regarding certain services that have become available, such as Internet access.
An electronic corridor that sends signals from one part of the computer to another, such as from the processor the memory. The bus sends signals in either 16 or 32bits.
Bus Topology
Connects each computer along a single length of cable, in a line. You can connect up to 30 users on this simple network. Installation is easy, and the network is relatively inexpensive.
A data measurement unit that is the equivalent of one character; a byte is made up of 8 bits of data, also know as an octet. Bits are grouped to form larger storage units, the most common of which is a byte. The word byte is a contraction of Binary Digit Eight.
Cable Modem
A device, not actually a modem that connects your PC to a cable television line instead of a phone line. The device enables you to have Internet access 24 hours a day. The connection is much faster than a dial-up modem.
Pronounced "cash", this is a special area of memory you compute uses on top of RAM memory. Cache helps boosts the performance of the computer by making information even more available than that stored in RAM.
Card Bus
A Pc Card slots that is a 32-bit bus-mastering slot. This slot is commonly the bottom slot on, laptops that support it.
CAT 5 Cable
There are categories, or levels, of twisted pair cabling. Each level describes the performance characteristics of wiring standards; Category 5 (CAT 5) is the best cable for any network-business or home. CAT 5 works equally well with 10Base-T with 100Bses-T.
-or- Central Processing Unit. The part of the computer that controls devices, components, and so on. Also called processor, the CPU is a printed circuit board that often includes slots for memory and device cards.
-or- Common Internet File System. A protocol that runs over TCP/IP and enables users from different platforms, such as Linux and the Mac, to use Windows operating systems.
Class A IP Addresses
These addresses are used for large networks. To identify a Class A Network address, the first octet uses the numbers from 1 to 126. Class A networks have an 8-bit network prefix; therefore, they are currently referred to as /8s 9pronounced "slash eights") or just "eight".
Class B IP Addresses
These addresses are mainly used for medium-sized networks, and the first octet values range from 128 to 191. Class B network have a 16-bit network referred to as/16s.
Class C IP Addresses
These addresses are reserved for smaller networks. The values for Class C range from 192 to 233. Class C network have a 24-bit network prefix; and are referred to as/24s.
Class D IP addresses
These addresses aren’t used for networks because they’re special multicast or broadcasting addresses.
Class E IP Addresses
These addresses, with values higher than 233 in the first octet, are used only for experimental purposes.
Coaxial Cabling
A fast, expensive network cable. Coaxial (coax) cable consists of a plastic jacket surrounding a braided copper shield, plastic insulation, and a solid inner conductor. The cabling is generally free from external interference and supports greater distances, and it is also a secure transfer medium.
Happens when two computers or other networking devices sand data at the same time to another computer, server, or device. When a collision occurs, the server, or network device sends a request back to the original computer asking for original data. It’s best to avoid collisions because the take longer for services to be delivered over the network and they add more network traffic. Switches and routers are good solutions.
Refers to the serial port on a computer. Often the COM port attaches a mouse, modem, or keyboard to the computer. Computers usually have two COM ports: COM1 and COM2.
Data Bits
Describes the number of bits number of bits used to transmit a piece of information, usually 7 or 8.
Packets of data that contain the source and destination address, as well as data intended for its target host. Each datagram contains all the information it needs to find the target host, no matter which paths the other datagrams have taken.
Data Link Layer
One of the ISO/OSI layers. The data link layer controls the flow of data through the network cards.
Dedicated Line
A special high-speed, hard-wired (limited flexibility) connection that is permanent. The connection is always active and therefore always ready.
Default Gateway
A physical device that connects two networks segments. The gateway address looks like an IP address.
Device Driver
The software needed to make a hardware device-sound card, mouse, CD-ROM drive, and so on work through the operating system.
-or- Dynamic Host Configuration Protocol. A utility for assigning TCP/IP addresses to workstations automatically.
A library of codes in Windows that presents a standardized format for programming. DirectX makes an application, such as a game, accessible to a wide variety of hardware features. Some hardware might nit be fully compatible with DirectX.
-or- Direct Memory Access. A method of transferring information directly form a hard disk, for example, into memory by bypassing the processor.
See Domain Name System.
Domain Name
IP addresses are difficult to remember, so domain names can also represent a computer on the Internet. Microsoft’s domain name, for example, is Domain names usually start with www, which stands for World Wide Web; however, www is not always included in an address. Some addresses route to a different prefixes than www; other addresses use a generic routing, so if you don’t use www, the link finds its way on its own.
Domain Name Server
See Domain Name System.
Domain Name System
-or- DNS. A method of matching IP addresses with domain names. When you type a domain name in the URL address area of your browser, that query is Transmitted to a Domain Name Server. A Domain Name Server maintains a database of domain names and IP addresses. The Domain Nam Server finds the IO address that matches the domain name and then sends your request on to that server. The process is called name resolution.
Also called download, this is the speed at which information travels from the destination server o you. Downstream speeds are often faster than upstream, because users download more often than upload; bandwidths for downloading are therefore extended.
A set software routines used to control input and output between the operating system and a device, such as a modem, network card or other computer equipment.
-or- Digital Subscriber Line. A digital technology that transmits data in both directions at once over copper lines (existing phone lines), just like the ones the ISDN service uses. DSL are around 160 Kbps. DSL lines are secure and offer low interference.
Dynamic Host Configuration Protocol
A protocol and cabling scheme that transfers data at the rate of 10 Mbps. Ethernet can use the bus or the spanning tree topology connected with various cabling types.
Extended Capabilities Port (ECP) Cable
This cable, which is used with an ECP enabled parallel port, enables data to transfer more quickly than standard cables. The ECP port must be enabled in the BIOS.
Fiber-Optic Cabling
A fiber-optic transmits data in pulses of light along specially manufactured optical fibers. Fiber-optic cable is lighter and smaller than traditional copper cables, and it’s immune to electrical interference. Fiber-optic cable also offers better signal transmission. Unfortunately, fiber optics is also extremely expensive. The cable is difficult to install and hard to repair; thus, maintenance is more difficult as well.
File Server
A computer with a fast processor and a lot of storage space (in the gigabyte range) that is used to store files in a client/server network.
See File Transfer Protocol.
Firewalls can be either hardware or software. Hardware firewalls monitor bandwidth usage and network or connection activity. They also protect the LAN from security breaches, perhaps authenticate users, and monitor incoming and outgoing e-mail messages. Software, or application, firewalls control access to the LAN from Internet, users, control LAN user’s access to Internet, and issue alerts for security breaches. A good firewall also logs all events and notifies the administrator of any problems.
A newer bus developed to make more effective use of audio and video applications. FireWire is extremely fast; the data transfer rates are more than three times that of PCI. FireWire is ideal if you want to use your PC mainly for games; its power would be wasted on general or common use, such as word processing. You can connect up to 63 devices in a chain a FireWire bus.
Fractional T1
A part of a T1 line. Fractional T1’s speed is less than T1 but better than ISDN and frame relay. Also, as your network grows, you can add fractional T1 lines to increase speeds.
Frame Relay
Frame relay supports speeds of 56 Kbps, transmits voice and data, and has no distance limits. Frame relay’s equipment, however, expensive, and the voice transmission quality isn’t the best.
Hardware or Software that acts as a translator between two different protocols; any device that provides access to another system.
Gateway Remote Access
A method of connecting to one computer to get to another. You might connect to the server at work, for example, in order to get your workstation there.
See gigabyte.
See gigabit.
Gigabits per second. Measures how much data transfers per second.
-or- Gbit. A Gigabit represents 1 billion bits.
-or- GB. A gigabyte contains 1,073,741,824 bytes. Giga-is the prefix for one billion in the metric system. You generally see gigabytes when talking about hard-disc capacity.
A part of the TCP/IP protocol that provides a menu-based interface to files on an intranet or the Internet; Gopher is an older service but is still used many places.
-or- Home Area Network. A new acronym for a network set up in the home.
-or- Hexadecimal. Hex stands for hexadecimal, which is the base 16 numbering system. Hex numbering uses the digits 0 to 9, followed by the letters A to F, and is a convenient method of representing binary numbers.
(Home Phone line, nonprofits association of industry leading companies working together to ensure the adoption of a single, unified phone line networking industry standard for vendors and manufacturers.
Any computer on a network that offers services to other computers.
Host Computers
Same as host; a networked computer that enables other computer connected to it to uses programs, access data, and so on.
-or- Hypertext Mark-up Language. A set of codes that creates the page formatting you see in a Web page; HTML is the standard for creating Web pages.
-or- Hypertext Transfer Protocol. The protocol that transfers documents from a Web server to your own computer. http, in lowercase form, is often the first thing you type in before an Internet address. HTTP indicates to the Web browser the protocol needed to locate the Web address.
A networking device that enables attached devices to receive data transmitted over the network. Most networks need a hub to help modify transmission signals and to extend the network past two workstations.
-or- Internet Control Message Protocol. One of the TCP/IP protocols. It helps IP communicate error information about the IP transmissions.
-or- Integrated Device Electronics. A popular hard disk interface standard that provides only medium-to-fast data transfer rates.
-or- Institute of Electrical and Electronic Engineers. Networking cabling and other equipment have standards that are set by the IEEE to ensure interoperability of products and services from vendor to vendor.
-or- Internet Group Management Protocol. One of the TCP/IP protocols. It enables IP datagrams to be broadcast to computers that belong to groups.
The Internet Assigned Numbers Authority, an organization that oversees IP address, Top-level domain and Internet protocol code point allocations.
See I/O port.
Institute of Electrical and Electronic Engineers
Integrated Device Electronics
See IDE.
Integrated Services Digital Network
Intelligent Home
-or- Also Smart Home or Smart Home. Intelligent homes vary from those having simple motion detectors outside to those that are fully connected and fully wired with automatic heating and cooling, security cameras, whole-house video and audio, and more.
International Organization for Standardization/ Open Systems Interconnect
International Telecommunications Union-Telecommunications Standards Section
An internetwork of smaller networks that spans the entire world. Each smaller network contains servers that displays information of various types on the Web (WWW, Word Wide Web). The Internet is a public network, available to all who have a computer with the appropriate software and a connection to the Internet.
Internet Group Management Protocol
Internet Protocol
See IP.
Internet Service Provider
See ISP.
Internetwork Packet Exchange/ Sequenced Packet Exchange
-or- Internet Network Information Center. To ensure that the IP addresses used on the Internet are unique, the InterNIC must assign any address used on the Internet. InterNIC is the controlling agency for IP addresses and domain names.
Interrupt Request
See IRQ.
A private Internet-that is, a network within your home network on which you publish documents to view you Web browser. You use these Internet tools – HTTP, HTML, TCP/IP, Web browsers, and more- to create and use the intranet. An intranet may or may not be connected to the Internet.
I/O (Input/Output) Port
A port on the computer to which you can attach hardware, such as a joystick. The I/O is the means by which data is transferred between the computer and its peripheral devices.
-or- Internet Protocol. One of the TCP/IP protocols that provides routing services over multiples networks. IP enables network packets to move data between network segments and to travel across routers. IP is a routing protocol, meaning that it directs datagrams from the source to the destination.
Ipv4 is a connectionless protocol for use on packet-switched Link Layer networks (e.g., Ethernet). IPv4 uses 32-bit (four-byte) addresses, which limits the address space to 4,294,967,296 (232) possible unique addresses. However, some are reserved for special purposes such as private m=networks (~18 million addresses) or multicast addresses (~270 million addresses).
Internet Protocol Version 6 (Ipv6) is a version of the Internet protocol that is designed to succeed Internet Protocol version 4 (IPv4).
IPv6 uses a 128-bit address, whereas IPv4 uses only 32 bits. The new address space supports 2128 (about 3.4x1038) addresses.
This expansion provides considerable flexibility in allocating addresses and routing traffic. It also eliminates the primary need for network address translation (NAT), which gained widespread deployment as an effort to alleviate IPv4 address exhaustion.
IP Address
An identifier for the ISP’s server. Often the IP address looks similar to this:
A utility included with TCP/IP that displays the IP address, subnet mask, and default gateway for all network adapter cards on your computer. IPCONFIG handy for checking a computer’s address quickly. It also can detect bad IP addresses or subnet masks.
-or- Internetwork Packet Exchange/Sequenced Packet Exchange. A protocol frequently used with Novell NetWare networks, although you also can use in with Microsoft networks. IPX/SPX supports many of Window’s features. Including NetBIOS, Windows sockets, and others.
A popular method used on the Internet and in the private networks to chat between computers and sometime share applications.
-or- Interrupt Request. A hardware signal sent to the central processing unit. Each device must send an IRQ before the CPU can process the request for service. Hardware lines carry a device’s signal to the processor. When the device wants to communicate with the processor, it causes an IRQ to gain the processor’s attention.
-or- Industry Standard Architecture. A 16-bit us design.
-or- Integrate Services Digital Network. A digital service that transmits data, voice and video. ISDN lines are copper, twisted-pair cabling that you can lease from your local phone company. ISDN supplies low noise, less interference, and good security. ISDN runs at speeds from 56 Kbps to 45 Mbps, depending on the cabling type.
-or- International Organization for Standardization/Open Systems Interconnect. The IDO/OSI model is a set of standards that define networks functionality. ISO/OSI sets standards for cabling, NICs, Protocols, and so on.
-or- Internet Service Provider. A company or service that provides access to the Internet for a monthly free.
-or- International Telecommunications Union Telecommunications Standards Section. An organization that sets international telecommunications standards that govern, in part, the definition of modem speeds and operations; formerly known as the CCITT.
A programming language that enables embedded motion on a Web page, thus embedded motion on a Web page, thus making the Web page more dynamic than static. Java programs you download from the Internet are usually safe from viruses or other harmful additions.
The fluctuation of a data packet with respect to the standard clock cycle.
-or- Joint Photographic Experts Group. A file format for graphics. A good format to use on the Internet, because the graphic is compressed when saved in this format. Use JPEG for Photographs, in particular.
Small switches that complete a circuit between two pins on an adapter card. When you adjust the jumpers, you can change the IRQ, base memory address, or I/Q port address. Plug and Play cards don’t have jumpers.
-or- kilobits per second. A measure of data transmission or network speed. 1 Kbps is 1,024bps.
The core of the operating system that interfaces directly with the hardware.
A kilobyte (K) contains 1,024 bytes. Your file sizes represented in the Windows Explorer, for example, are listed in kilobytes if the files are small. Kilo- is the prefix for 1,000 in the metric system.
L1 cache
There are two levels of cache in a computer: L1 (level 1) and (level 2). L1 cache, also know as internal cache, is a small amount of fast memory. See also L2cache.
L2 cache
The L2 cache is linked directly to the processor to make it react quicker to processor request. All computers have L1 cache; not all computers have L2. See also L1 Cache.
-or- Local Area network. A set of computers and other equipment (printers, hubs, and soon) that communicate through local cabling using networking protocols. A LAN might cover computers in one room or office, in a building, or spanning several buildings.
-or- Local-Area Wireless Network. A network that uses radio transmissions to communicate with other computers.
Leased Line
Refers to a phone, ISDN, xDSL, frame relay, or other line that rented for exclusive, 24 hours-a-day, 7 –days-a-week use.
A free operating system that began in 1991. The Linux kernel runs on Intel and Alpha Hardware. The program is in the general release and available under the GNU General Public License. There are hundreds of "flavors" of Linux available, including Mandrake, Red hat, and many others.
Local Area Network
Logical drive
A logical drive isn’t a physical drive in your computer, rather it is a partition on one drive that is given an arbitrary letter, such as E, F, G and so on.
A protocol used in home and building automation. You can connect up to 32,000 devices to a LonWork network, intelligent control devices, called nodes; communicate with each other by using the LonWorks protocol. Each node has the intelligence to use the protocol to perform its own control functions. Nodes might be sensors, motion detectors, instruments, and so on.
Mac (Media Access Control) address
An Ethernet address also is called a MAC address. It’s a number written as 12 hexadecimal digits-0 through 9 and A through F-as in 0080001021ef. Alternatively, a MAC address might have six hexadecimal numbers separated by periods or colons, as in 0:80:0:2:21ef. The MAC address is unique to each computer and does not identify the location of the computer, only the computer itself.
Network maps describe how a network is put together. Not only does the map show where the computers and peripheral are located, but it also tracks important information about wiring, networking hardware, and even software used throughout your system.
Mapping a Drive
A method of reconnecting to a network drive and folder as a shortcut. You assign a drive letter-such as J, K, L, M, N or other drive not currently in use-to represent the path to the resource.
-or- megabits per second. A measure of data transmission or network speed equalling 1 million bits (or 1,000 kilobits) per second.
See megabytes.
A megabit (Mbit) equals 1,048,576 binary digits, or bits of data. In general, a megabit is the equivalent of 1 million bits.
-or- MB, M, or meg. A megabyte (MB) contains 1,048,576 bytes. Mega- is the prefix for 1 million in metric system. It is used in representing file size, as well as computer memory and hard disk capacity.
Mesh Topology
Represents a wide area network (WAN) used in a large corporations, universities, and government agencies. Mesh uses multiple paths to connect multiple sites or buildings.
-or- Megahertz. One million cycles per second. A unit of measure for frequency.
The main circuit board on a computer. The motherboard includes processor, RAM, support circuitry, and a bus controller.
Motion JPEG
A variation of JPEG, this is a compression scheme for video files. See also JPEG.
-or- Multimedia Personal Computer. A specification for multi media hardware-speakers, sound cards, video cards, Cd drives, and so on that ensures the hardware is compatible, reliable, and meets certain quality standards.
-or- Moving Picture Experts Group. A graphic file format that enables video to be stored in compressed form.
MS-DOS-based application
MS-DOS applications were built for the original MS-DOS operating system. Some MS-DOS programs can run in Window and others cannot.
The simultaneous of two or more programs in a Windows or OS/2 operating system.
A process by which Windows can multitask portions, or threads, of a program.
Narrowband Transmission
One in which the data transfer is slow or has a small rate.
-or- Network Driver Interface Specification. A set of functions that causes a request to be submitted to the operating system or causes a request to be submitted to the operating system or causes a local action to be performed. Mainly, the NDIS enable protocol drivers to send and receive packets on the network.
-or- NetBIOS Extended User Interface. A Microsoft protocol you can use with any Windows program-most commonly used with Windows for Workgroups, Windows 95/98, and Windows NT, and very seldom used with Windows Me, 2000, and XP, NetBEUI is easy to set up, provides good performance, and is a fats protocol. NetBEUI uses very little memory and also provides good error detection over the network.
-or- Network Basic Input/Output system. A programming interface for developing client/server applications; NetBIOS also works with other protocols and various network types.
A system that connects two or more computers plus peripherals (Printers, CD-ROM drives, scanners, and so on) so that all computers can communicate and share resources with each other.
Network Adapter
See network interface card.
Network Address
Another way of referring to the IP address. The IP address for a computer, printer, or other device on the network. See also IP.
Networks Applications
Network applications come in two parts: client and server. The server part of the application is installed on a server computer, on a workgroup network; it is installed on a workstation that serves as a host. The client part of the software installs on the rest of the computers on the network. The client requests some service, and the server grants the request.
Network Commands
Windows includes several network commands you can use at the MS-DOS prompt. These commands enable you to view your current network connections, view any computer’s shared resources, and even create permanent connections, or drive mappings.
Network Interface Card
-or- NIC. Also called network card or a network adapter, this is a circuit board installed in your computer that uses specific software drivers to work with your computer and attaches to the network by means of a network cable or a wireless connection.
Network Layer
One of the ISO/OSI layers. The network layer defines the protocols for data routing, to make sure the data gets the correct destination.
Network Operating System
-or- NOS. Designed specifically for a server, a NOS offers many features and tools that help you manage clients, applications, security, and other facets of the network.
Network Path
A path that leads to a computer on the network, and then to a folder or file on that computer. For example, \ Sue\My Documents\My Pictures leads to the My Pictures folder on Sue’s computer over the network. (The double backslashes tell the operating system to locate the following over the network instead of on the local computer.)
-or- Network File System. NFS enables a computer to use files and peripherals as if they were local.
Any device connected to a network, such as a client, server, hub, printer, and so on.
Interlacing refers to how a monitor refreshes, or redraws, the screen, Interlacing monitors skip every other line during the redraw process, thus producing a flicker or jitter on the screen. Noninterlaced monitors scan every line, providing the best screen quality.
Null Modem
A cable used to connect two computers. Data flows from one computer to the other, only in one direction at a time, so the two computers cannot try to send data to each other simultaneously. A null modem cable connects the serial ports.
Operating System
-or- OS. The software that controls hardware resources and enables you to interact with the computers applications. Windows XP, Macintosh system 8,9 and OS X, and Slackware are operating systems.
OSI Model
-or- Open System Interconnection. A seven-layer model that establishes a standard set of protocols for interoperability between networked computers.
Data is over a network in packets, or blocks. Each packet not only contains a part of the data you want to send, but only contains a part of the data you want to send, but only contains the name of the sender and receiver and some error-control information to helps make sure the packet makes it to its destination in one piece.
Parallel Port
An input/output port that manages information 8 bits at a time; parallel ports are often used for connecting printers t a computer as well. You generally can find a high-speed direct parallel cable at any computer store.
Refers to dividing your hard disk into sections. The operating system treats different partitions on a hard disk as if they were separate drives.
Patch Panel
Patch panels contain 8,12 or 24 jacks within a strip for easy connection to solid cables. You can attach the patch panel to the wall; insert the patch cables on the other side leading to your hub for safe and effective wiring of your network.
-or- Personal Computer. A microcomputer for use by an individual, as in an office or at home or school. Also, an IBM-compatible computer, as opposed to a Macintosh.
PC Card
A type of PCMCIA card. The card is smaller than normal adapter cards and works with portable computers to provide functionality for modems, sounds, videos, and other devices.
-or- Peripheral Component Interface Bus. An Intel specification that defines a local bus that enables up to ten PCI- compliant expansion cards to be plugged into the computer.
-or- Personal Computer Memory Card International Association. PCMCIA is a standard for portable computers.
The PCMCIA card is usually the size of a credit card. There are several versions, or types, of PCMCIA cards; the types define the thickness and uses of the card.
Peer-to-Peer Network
A network in which all computers of the network have an equal rank; all share their resources-including files, folders, drives, printers, and so on – with all others on the network. See also workgroup network.
Similar to rights, permissions are characteristics given to users of a network to allow or prevent access to files and other resources on the network. See Rights.
Physical Layer
One of the ISO\OSI layers. The physical layer defines the cabling.
The PING command sends TCP\IP packets to the designated computers. If PING is successful, TCP/IP sends the packet back. Use PING that the configuration is correct, that local computers are communicating with each other and that remote computers are communicating with local computers.
Plug and Play
A windows specification that makes it easier to install adapter cards and other hardware. All you need to do is insert the hardware and turn windows on. Windows automatically configures the IRQ, DMA and other settings for the hardware.
-or- Point of Presence. The e-mail host name. The host is the server that holds the e-mail messages for you until you log on and get your messages.
-or- TCP. In TCP/IP and UDP networks, a port is an endpoint to a logical connection and the way a client program specifies a specific server program on a computer on a network, some common ports are HTTP at Port 80 and FTP ported at 209data0 and 21 (control), Some ports have umbers that are preassigned to them by the IANA.
A term for sending line network, you use electrical outlets in your home to attach computers for sharing files, printers, Internet accounts and peripherals. It’s important to note that the transmission speeds for power line network are slow. Data transmission speeds are around 350 Kbps.
-or- Point-to-point Protocol. This protocol is used with remote access, because it enables computers to load other protocols-such as TCP/IP, NetBEUI, and so on in addiction to the PPP.
-or- Point-to-Point Tunnelling Protocol. A protocol that enables you to have secure access to a virtual private network.
Presentation Layer
One of the ISO/OSI layers. The presentation layer identifies the data is formatted.
-or- Primary Rate Interface. PRI lines are a type of ISDN line that is more expensive that BRI because of a higher bandwidth connection. PRI supplies speed up to 1.5Mbps.
Describes a protocol or communications that was developed by a company rather than one that follows established standards.
Part of software is a language that the computers can use to communicate, called a protocol. Windows contains three such protocols from which you can choose.
Proxy Servers
These servers control what the user can and cannot access on the Internet. Proxy servers might also reduce user wait times by relieving bandwidth congestion, offer network security features, log events, and so on. Some proxy server software installed on a dedicated computer that acts as a gateway and barrier between the LAN and the Internet.
Short for quality of service. QoS is Microsoft’s addition to windows 2000 and XP, although it is used by other manufacturers, it enables a smoother flow of traffic on the network. An administration can set higher and lower priorities on a network using the QoS settings.
-or- Random Access Memory. Temporary memory in a computer. The memory stores the data related to a task that the processor is currently dealing with.
-or- RAM Digital-to-Analog Converter. In a video card, RAMDAC is the electronic component that changes the digital video signal of the card to a signal the monitor can read. RAMDAC speed affects the speed of images appearing on the screen. The standard RAMDAC is 135 Mhz, although some cards are faster. The faster the RAMDAC the better.
-or- Reverse Address Resolution Protocol. One of the TCP\IP protocols, it translates physical network addresses to into IP addresses.
Read-only Access
Sharing option that enables others to open and view folders, or open, view and copy files, however read only access doesn’t enable others to modify a file or delete anything.
Real Time
Describes an event or process that is currently taking place. A good example is when; you are talking on the telephone to someone. You are talking in real time. When you leave a message on someone’s answering machine and that person hears the message later, that person is not hearing in the real time.
Refresh Rate
Describes how many times per second the image is refreshed, or redrawn on the screen. The faster the refresh rate, the lesser flicker you see on the screen, The default setting for most monitors is 60Hz, but you should use 75 to 85 Hz to deduce flicker and eye strain.
The area of windows operating systems that contains all configuration files for the computer users. For example, the registry lists user preferences. Desktop colors, fonts and program settings. If the registry becomes corrupted, Windows might stop working altogether.
Remote Access
Refers to the process of attaching to a network from another location and accessing resources from the remote computers.
Remote Administration
Enabling remote administration allows a user to create, change and monitor shares on the computer. Windows lets you assign a password to this permission so that only a person who knows the password can perform these tasks. The person who knows the password can monitor the workstations from any computer on the network.
Remote File Transfer
Another common method of remote access to file transfer. File transfer involves uploading a file to or downloading a file from the remote computer.
Remote Node
The most common method of remote access is when a computer connects to an office or corporate network. The remote computer user accesses any works as if he or she were actually in the office, sharing programs and files with co-workers.
Remote Registry Service
A network service that enables programs such at the System Policy Editor or System Monitor to change the Registry in a network computer.
A network device that boots and amplifies an analog signal in the network.
Repeater Functions
Refer to the retransmission of network packets when a collision or timing problem takes place.
Describes the number of pixels a device such as a scanner or printer applies to an image. Resolution is measured by a gird, such as 300-300 pixels 9or dots0 per square inch. The higher the resolution, the better the image output and the more expensive the scanner.
Characteristics given by a user or administrator on the network to prevent or allow access to files on the network. Common rights include all, execute, read only, write, and so on.
Ring Topology
A networking layout in which computers are connected by a closed Loop, or ring. The ring topology uses a hub to redirect network packets.
A four-wire connector used to join a telephone line to a wall plate or a communication peripheral, such as a modem.
An eight-wire connector used to join twisted-pair networking cable.
-or- Read-Only Memory. A chip that permanently stores data, also called firmware.
A network device that connects two or more network segments; a router then can choose the best way for network packets to travel the network to arrive quickly and efficiently at their destination.
Cable. This cable transmits data at about a 20 Kbps. A serial cable generally used for connecting a computer to a peripheral device, the RS-232 has a maximum cable limit of 15 meters, or about 50 feet. Used for Direct Cable connection in windows. See also direct cable Connection.
RS-485 is a serial connection port that enables you to connect from 10 to 32 devices.
Script Files
Mini-programs that automate logging in to another network, such as a remote network or the Internet. Generally included in a script file is the username and password. When you dialup another computer on a network, the script enters your username and password, so you don’t have to type them.
-or- Small Computer System Interface. A standard high-speed parallel interface used to connect the microprocessor to peripheral devices and printers, or to connect computers together or to a LAN.
-or- Synchronous Dynamic Random Access Memory. SDRAM is currently the standard memory type. SDRAM supports burst access modes.
Serial Port
A serial port transmits data a bit more slowly than parallel ports, one bit at a time. Serial cables transmit data sequentially over only one pair of wires. Since parallel cables transmit data simultaneously over multiple lines, parallel is the faster of the two connection methods. A serial is also a COM port.
The computer on a network that provides services-such as file storage, print management, Internet access, and so on-to other computers on the network.
Session Layer
One of the ISO/OSI layers. The session layer maintains the connection, or session for as long as it takes to transmit the packets. The session layer also performs security and administration functions.
A resource that is designated as usable by two or more computers- a folder or printer, for example, can be considered a share.
Share-Level Access Control
With a peer-to peer network, you use share-level access control to enable all users to share files, folders, printers, and other resources on their computer. Each user sets his or her shares, adds passwords if desired, and so on. Sharing the process of several computers using a resource in a cooperative manner.
The process of several computers using a resource in a cooperative manner.
Shielded Twisted-Pair (STP) Cable
Cable with a foil shield and copper braid surrounding the pairs of wires. STP provides high-speed transmission for long distances.
-or- Serial Line Internet Protocol. An older protocol that isn’t used much anymore; however, you still might run into servers using SLIP.
Smart Home
See intelligent home.
A smart phone takes multiple technologies- cell phone, faxes pagers, PDAs, and so on- and integrates them into one product you can use to perform all your tasks.
-or- Server Message Block. SMB enables a computer to use network resources as if they were, local. SMB is more commonly used these days, since Macintosh and Linux make use of the protocol.
-or- Simple Mail Transfer Protocol. The e-mail host name. SMTP is part of the system that sends the mail out to other e-mail servers on the Internet.
-or- Simple Network Management Protocol. A set standards for communications with devices-such as routers, hubs, and switches-connected to a TCP/IP network. SNMP, a TCP/IP protocol, manages and monitors the network.
Spread-Spectrum Radio Frequencies
RF Standard physical interface that can pass through heavier walls. Spread-spectrum signals are fairly secure against tempering from outside sources. Additionally, spread-spectrum products provide 1 to 2 Mbps data rates at a range from 50 feet to 1,000 feet, depending on the building construction, interference sources, and other factors.
-or- Secure Sockets Layer. A protocol designed to enable encrypted, authenticated communications across Internet.
A computer that is not connected to a network.
Star Topology
Also called spanning tree, the star topology uses a hub with its own cable, and signals are passes from station to station until the designated computer is found.
Describes the constant flow of audio and video files so that they look like they’re running in real time, without pauses, jitters, or other interference.
Subnet Mask
Enables the computer in one segment of a network to see computers in another segment. The ISP uses subnets mask-such as communicate with other segments on the Internet network.
Sub network
A smaller network connected to a larger and more powerful system by a bridge or router computer’s network or disk access in a graphical manner. The programs enable you to monitor running processes, memory usage, dial-up access, and more.
System Policy Editor
A network administrator program you can use with client/server network. Using the System Policy Editor, you can configure settings the control individual users, individual computers, or group of users.
A high-quality, reliable communications line. Total speed is 1.544 Mbps. Because of the expense, however, T1 is best for corporations connecting a large number of users.
A T-connector is also used with coaxial cable. T-connectors attach two thin Ethernet cables and provide third connections for the network interface card.
-or- Transmission Control Protocol. A higher-level protocol than IP, it provides continuing connections between programs. TCP also makes IP datagrams into smaller and faster. TCP divides datagrams into smaller segments to fit the physical requirements of the servers on the network. It then uses IP to transmit segments of data.
-or- Transmission Control Protocol/Internet Protocol. A network protocol used on the Internet and on local area networks. TCP/IP is a set of communications protocols supported by various manufacturers and vendors. Corporations, universities, and other agencies use TCP/IP to communicate over the Internet.
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