Surveillance Glossary

A

Alarm

Alarm is a facility that allows external alarms like PIR's, reed switches, vibration sensors etc. to be connected to the CCTV switcher so that a nominated camera is switched on when an alarm signal is received.

Algorithms

Complex mathematical formulae or rules used to solve problems. In video, they are used to achieve digital compression of a video picture.

Analog

Representation of data by continuously varying quantities.

Analog circuits

Electronic circuits made up of components that can handle analog signals. Examples: Resistors, capacitors etc.

ATM

It is a type of ISDN technology using constant size 53 byte cells instead of variable size packets. Because cells do not change size, they switch much faster and more efficiently.

B

Backbone

Backbone is the infrastructure that is used to inter-connect the various local area networks to build a wide area network.

Bandwidth

Bandwidth is the range of frequencies or data that pass through an electrical/electronic amplifying, processing or transmission unit without attenuation or loss

Binary

A base 2 numbering system using two digits 0 and 1.

Bits

It is the short form for binary digit

Bridge

A network device that logically separates a single network into segments.

Brightness

Brightness represents the intensity of illumination of the reproduced picture.

Byte

Group or word of bits. Usually has 8 bits.

C

Camera

Camera is an electronic device that converts light into an electrical signal.

CCD

Charge Coupled Device is a solid-state device in a camera that converts light falling on it into an electrical signal.

CGI

The Common Gateway Interface (CGI) is a standard for interfacing external applications with information servers, such as HTTP or Web servers. A CGI program can be written in any language that allows it to be executed on the system, such as: C/C++, PERL, Visual Basic etc.

Compression

It is a process of reducing the size of digital signal.

Compression ratio

It is the ratio between the size of data before compression and after compression.

Compressor

It is a process of reducing the size of digital signal.

CPU

Central Processor Unit. It is the brain of a digital system like the computer, where all the manipulation or processing of digital data is done. Its speed is measured in Hertz. It also tells the number of instructions it undertakes per sec.

D

Data Rate

It is amount of data being handled by a device every second.

DDNS

DDNS stands for Dynamic Domain Name Server: This is a service provided by different service providers, and is suitable for situations where the IP address is dynamic and keeps changing. The user registers a host name with a service provider and whenever the dynamic IP address changes, the DDNS service provider automatically updates the DNS servers all over the world

Decimal

A base 10 numbering system using ten digits 0, 1,2,3,4,5,6,7,8,9.

DHCP

Dynamic Host Configuration Protocol is used in a TCP/IP protocol network to send client configuration data including TCP/IP address, subnet mask to the clients.

DNS

Domain Name Server (DNS): When the user types in 'www.panasonic.com ', the DNS server in the network converts it into an IP address, which is then used in all communications.

DSL

Digital Subscriber Line is a high-speed network connection using standard POTS or PSTN telephone cable

DSP

Digital Signal Processing chip is like a mini computer with its own RAM, CPU and different application software. As required the software is activated to manipulate the digital signal.

Dynamic Address

This is not a permanent address and is a good solution to overcome the shortage of IP addresses. The Dynamic Host Configuration (DHCP) server allocates temporary IP addresses to the devices connected to the network. If a device logs on to the network, it is given a temporary IP address for a fixed time period or the same IP address is given to another device when the original user logs off.

E

F

Firewall

A combination of hardware and software that protects the network from attack by hackers who could gain access through the public networks.

Fixed Lens

A lens with fixed focal length.

Frame

Frame is the basic unit of a moving picture. At least 24 frames per sec are required for a moving picture to look continuous.

Frequency

The number of completed cycles of a waveform that occurs in a given length of time. Usually specified in cycles per second (Hertz)

Frequency Range

Frequency Range is the number of different frequencies that are included in the analog signal Usually specified in cycles per second (Hertz)

FTP

File Transfer Protocol (FTP) is a type of TCP, which is specifically used to transfer files between computers and uses the Port 20 or 21.

G

Gateway

The hardware and software needed to connect two disparate network environments

GUI

Graphical User Interface interfaces the PC to any external device. Hot areas on the computer screen can be programmed to activate a function or activity in the device.

H

Hard disk

A magnetic medium for storing digital information on most computers and electronic equipment that process digital signal.

Hexadecimal

A base 16 numbering system using ten digits and 6 alphabets -0,1,2,3,4,5,6,7,8,9,A, B, C, D, E, F

HTML

Hyper Text Markup Language is a set of codes to format text and graphics that will be displayed in a browser. The code defines how the data will be displayed.

HTTP

Hyper Text Transfer Protocol: The protocol used for communication between a Web server and Web browser and usually uses the port 80

Hub

A network device that serves as a central connection point for several devices. A hub repeats the signal it receives on one port to all other ports.

I

IEEE

Institute of Electric and Electronics Engineers Inc. is an international organization that sets standards for various electrical and electronic issues

Impedance

Impedance is the input and output characteristic of any electrical system and is measured in ohms. For maximum signal transfer, the input and output impedance should be the same

IP address

It is part of the TCP/IP protocol suite and is responsible for network addressing and routing.

Iris

Iris is a diaphragm which is inbuilt in a lens that can be adjusted either manually or automatically to vary the amount of light passing through the lens and falling on the CCD chip.

ISDN

Integrated Services Digital Network is a telecommunication standard that is used to digitally send voice, data, and video signals over the same lines.

ISP

Internet Service Provider is a company that provides direct access to the Internet for home or business users.

J

Java

A programming language developed by Sun Microsystems which can run on any platform which has a Java Virtual Machine installed.

JPEG

Joint Photographic Expert Group is an ISO standard for still or single frame compression.

K

L

L2TP

Layer 2 Tunneling Protocol is a non-proprietary protocol created by the Internet Task Force for encrypting IP packets for transmission through the Internet. The host and destination routers must have the L2TP protocol installed to create a Virtual Private Network.

LAN

Local Area Network is a small network usually restricted to single or close by buildings.

LASER

Light amplification by stimulated emission of radiation. A laser produces a very strong and coherent light of a single frequency.

Lines

It is the measurement of resolution for an analog video signal. Higher the bandwidth of the signal means a higher number of picture lines.

Linux

A version of Unix developed by Linus Torvalds. Runs on Intel based PC's and is generally free.

Luminance

Luminance is that part of the video signal which contains the information on the brightness of the picture

M

MAC

Media Access Control is a part of the network interface card NIC) that controls the way multiple devices use the same media channel.

Mbps

Mega (106) bits per sec. It is an indication of data rate

MPEG

Moving Picture Expert Group is an ISO standard for moving image compression.

MPEG 1

A MPEG standard for compressing scanned images with audio. Bit rate is from 1.5Mbps to 3.5 Mbps.

MPEG 2

A popular MPEG standard for interlaced video signal with high quality audio with a scalable bit rate from 1.5 Mbps to 100 Mbps. Accepted as a HDTV and DVD standard

N

NIC

Network Interface Card connects any network device to the transmission medium.

Noise

It is an unwanted signal generated by electronic components. The noise in a video signal causes a grainy or snowy effect on the image.

NTSC

National Television System Committee is a color television system and the standard used in the USA and Japan. NTSC has 525 horizontal scanning lines and 60 fields per sec.

O

Ohms

Ohms is a unit for measuring resistance or impedance of any electrical device

Operating System

It is a software program installed in a microprocessor-based device that controls the functionality of the device.

P

Packet

A unit of data sent over a network and includes a header with addressing information and the data itself.

Packet switching

The process of breaking messages into packets at the router for easier transmission over a WAN.

PAL

Phase Alternating Line is a color television system and the Standard used in Western Europe, Australia, parts of Africa and Asia. PAL has 625 horizontal scanning lines and 50 fields per sec

Ping

A TCP/IP utility used to test whether another host is reachable.

Pixel

Picture element or cell, is the basic unit of a digital image.

POP3

Post Office Protocol is used to download email from a SMTP email server

POTS

Plain Old Telephone System is acronym for Public Switched Telephone Network (PSTN), the traditional analog telephone network.

Protocol

A pre-defined set of rules that dictate how computers or devices communicate and exchange data on the network.

PTZ

A camera with a Pan Tilt head and Zoom lens.

Q

R

Radio frequencies

Frequencies that is used in the wireless transmission of data, audio and video signals.

RAID

Redundant array of independent disks is a configuration of multiple hard disks which provide fault tolerance incase one of them fail.

RAM

Random Access Memory. Electronic chips known as memory that can store digital information when power is applied to it. Its capacity is measured in kilobytes (KB).

Resolution

Resolution is a measure of picture definition and clarity and is represented by number of pixels. Higher number of pixels = Higher resolution.

RJ 45

It is a connection mechanism that allows up to eight wires (or four pairs) to be connected to the network

Router

Connects two networks and allows packets to be transmitted and received between them. A router determines the best path for data packets from source to destination

RS 232

It is a communication protocol used for communication between microprocessor-based devices

S

Scalable

A process where the output changes up or down depending upon the input level.

Server

A powerful computer that provides resources to the clients on the network.

Signal to Noise

It is the ratio between the signal voltage and the noise voltage generated by an electronic circuit. It is measured in decibels (db)

SMPTE

Society of Motion Picture and Television Engineers

SMTP

SMTP stands for Simple Mail Transfer Protocol. This is the protocol used to send emails. The email first goes to the SMTP server in the host network and from there it goes to the SMTP server in the destination network.

SNMP

Simple Network Management Protocol (SNMP) is the management protocol created for sending information about the health of the network to network management devices.

Static Address

The device is given a fixed and permanent IP address. This address must be obtained from the network administrator or ISP.

Subnet Mask

A group of selected bits that identify a sub network within a TCP/IP protocol.

T

T1

It is a digital connection leased from the telephone company. The bandwidth of this connection is 1.544 Mbps

T3

It is a digital connection leased from the telephone company. The bandwidth of this connection is 44.736 Mbps

TCP/IP

Transmission Control Protocol /Internet Protocol was developed by the Department of Defense as a internetworking protocol that breaks data packets in segments, numbering them and send them in random order. The receiving device reassembles the data. It is the de facto standard for communication on the Internet

Topology

The physical and logical layout of the devices in a network.
Transceiver: A device that transmits and receives network signals.

Twisted pair

Twisted pair is a type of balanced cable in which a pair of cables is twisted and the signal is divided between them.

U

UDP

UDP stands for User Datagram Protocol. This is similar to TCP, except that in UDP there is no acknowledgment that the packet has been received at the destination. This is known as 'connection less'

V

Video card

It is card in a PC or any other device which grabs each frame of a moving image then digitizes it and even compresses it if required.

Video Motion Detection

Video Motion Detection is a device that can detect unwanted movement in the picture and then generate an alarm

VMD

Video Motion Detector is a device that can detect unwanted movement in the picture and then generate an alarm.

VPN

Virtual Private Networks can be set up in the Internet by encrypting the packets at the host server and than sending it to the destination server, where it is decoded. This allows secure communication between two locations.

W

WAN

Wide Area Network is a network that crosses local, regional and international boundaries.

Wavelet

It is a new standard for still or single frame compression that uses the frequency domain.

Web browser

A computer program that uses the Hypertext Transfer Protocol (http) and is used on a workstation to communicate with other devices on the Web.

X

Y

Z

Zoom Ratio

Zoom Ratio is the ratio between the maximum and minimum focal length of a zoom lens