Specifications

124 VISTA AT A GLANCE V5 - FOR MORE INFORMATION VISIT: V I S T A - C C T V. C O M / I P
GLOSSARY OF TERMS
Intranet - A network connecting a related set of standard Internet
protocols and files in HTML format with employees using Internet
browsers in an organisation’s network and within the corporate firewalls.
IOs - Input/Outputs.
IP (Internet Protocol) - The Internet Protocol is a method of transmitting
data over a network. Each computer (or host) on the Internet has at
least one address that uniquely identifies it from all others.
IP address - An IP address is simply an address on an IP network used
by a computer/device connected to that network.
IR (Infra Red) - A range of frequencies lower than visible red light used
for covert surveillance or as a low cost wireless video link.
Iris (Iris Diaphragm) - Adjustable diaphragm that regulates the amount
of light passing through a lens.
J-PEG (Joint Picture Expert Group) - A popular suite of digital
compression tools. Originally for use with “still” pictures but often used
in CCTV products.
KB - Kilobyte, or one thousand bytes or characters of information.
LAN (Local Area Network) - A data-communications system confined
to a limited geographic area (up to about 10km) with moderate to high
data rates (100 kbps to 100 Mbps). The area served may consist of a
single building, a cluster of buildings or a campus-type arrangement.
The network uses some type of switching technology and does not use
common carrier circuits (although it may have gateways or bridges to
other public or private networks).
LCD (Liquid Crystal Display) - A type of flat screen display.
LED - Light Emitting Diode.
Lens Calculator Software - A computer program for specifying correct
lenses.
Lens Calculator Wheel - Used for calculating a lens size or distance
from a camera to the subject.
Line Amplifier (Video Line Corrector) - A device to make good the loss
of signal strength and quality due to long cable runs.
Line Lock - To synchronize the field sync pulses of an AC powered
camera to the frequency of the voltage input (line voltage).
Linux - A freeware, clone version of the UNIX System V release 3.0
kernel that runs on PC x86 machines and other platforms.
Looping - Video input of a piece of video equipment both unterminated
and including the relevant sockets for the extra coaxial cables.
Loss - A reduction in signal level or strength, usually expressed in dB.
LPC - Loss Prevention Council.
Lumen (LM) - The unit of luminous flux. It is equal to the flux through a
unit solid angle (steradian) from a uniform point source of one candela
or to the flux on a unit surface of which all points are at a unit distance
from a uniform point source of one candela.
Luminance (Y) - The part of a video signal that consists of the
monochrome data.
Lux - Metric measure of the light striking a surface. The light available
from that surface will depend on how reflective it is.
MAC (Media Access Control) Layer - The protocol that controls access to
the physical transmission medium on a LAN.
MAC Address (Media Access Control Address) - A MAC address is a
unique identifier associated with a piece of networking equipment or
more specifically its interface with the network.
Macro - Feature allowing you to pre-programme frequent system
configurations for selection by a single keystroke or optionally by alarm
inputs.
Mask - See Privacy Zones
Master Code - The operators code for the system that has additional
privileges such as being able to delete other user codes.
Matrix Switcher - A switcher able to route any of its camera inputs to
any of its monitor outputs; a name usually reserved for large systems
that often includes telemetry control.
MD (Motion Detection) - Recording method for digital surveillance
systems. When someone walks in front of a camera, the pixels change
and the DVR defines this as motion. The surveillance system will then
record these images to the hard disk. This is a popular recording setup
as every event recorded is actually motion driven as opposed to a static
image if the system was set to record continously.
Mechanical Focus (Back-Focus, Racking) - The mechanical aligning of
the imaging device with the focal point of the lens; most important on
zoom lenses to ensure the image stays in focus throughout the zoom
range.
Megabyte (Mb) - A unit used in measuring the amount of information a
computer can store, which has the value 1048576 bytes.
Micro - Order of magnitude; 10–6.
Microwave - Radio frequencies between 1 - 30 GHz used for video
transmission over medium/long distance.
Milli - Order of magnitude; 10–3.
Modem - Used with PSTN telephone lines to connect a fastscan system
to the dial up BT network.
Modem (Modulator-Demodulator) - A device used to convert serial
digital data from a transmitting terminal to an analogue signal
(carrier) for transmission over a telephone channel or to reconvert the
transmitted analogue signal to serial digital data for acceptance by a
receiving terminal.
Modulate - To change or vary some parameter such as varying the
amplitude of a signal for amplitude modulation or the frequency of
a signal for frequency modulation. A Modulator is the circuit that
modulates the signal.
Monochrome - Black and white, not colour.
Motion JPEG - Motion JPEG is a simple compression/decompression
technique for network video. Image quality is controlled by adjusting the
compression level, which in turn provides control over the file size, and
thereby the bit rate.
M-PEG (Moving Picture Expert Group) - A suite of digital compression
tools specifically designed to video images.
MPEG-4 - A group of audio and video coding standards and related
technology. The primary uses for the MPEG-4 standard are web
(streaming media) and CD distribution, conversational (videophone), and
broadcast television.