Specifications

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GLOSSARY OF TERMS
Multicast - Bandwidth-conserving technology that reduces bandwidth
usage by simultaneously delivering a single stream of information to
multiple network recipients.
Multimode Fibre - An optical fibre with a core diameter of 50 to 100
microns. Its core causes some distortion and provides less bandwidth
than single-mode fibre.
Multiplex (Time Multiplex) - Using one carrier to send more than
one signal. In video multiplexers, achieving this by sending a different
camera’s output in each successive field or frame of a video signal, in a
form that can later be retrieved as single camera pictures.
NACOSS (National Approval Council for Security Systems) - Now
replaced with the NSI.
Native - The raw memory capacity of a given media. The memory
capacity of tapes is often specified including the tape drives 2:1
compression capabilities. i.e. a 12GB native tape will be specified as
24GB etc. Digital hard disk recorders cannot use the tape drives 2:1
compression capabilities.
Nano - Order of magnitude; 10–9.
N/D (Neutral Density) - A filter that attenuates light equally over the
whole visible spectrum.
Network - A series of points connected by communications channels.
Network connectivity - The physical (wired or wireless) and logical
(protocol) connection of a computer network or an individual device to
a network.
NIC (Network Interface Card) - Board that provides network
communication capabilities to and from a computer system. Also called
an adapter.
NICEIC - National Inspection Council for Electrical Installation
Contracting.
Noise - Undesired signal(s) that corrupts the original video signal and
may reduce image quality.
NSI - National Security Inspectorate.
NTSC (National Television Standards Committee. See EIA) - Colour TV
system used in the USA.
Null Modem - A device that connects two DTEs directly by emulating
the physical connections of a DCE.
NVM - Non Volatile Memory.
Ohm - The unit of resistance. The electrical resistance between two
points of a conductor where a constant difference of potential of 1 Volt
applied between these points produces in the conductor a current of 1
Ampere, the conductor not being the source of any electromotive force.
It can be represented by the formula V = I x R, where: V = Voltage I =
Current R = Resistance.
OSD (On Screen Display) - The ability of a camera or a piece of camera
control equipment to display its set-up menu on a display monitor.
Thereby greatly simplifying installation.
OSI (Open System Interconnection) - An architectural model developed
by the ISO for the design of open systems networks. All communication
functions are divided into seven standardised layers: Physical, Data Link,
Network, Transport, Session, Presentation and Application.
Overscan - A video monitor condition in which the raster extends
slightly beyond the physical edges of the CRT screen, cutting off the
outer edges of the picture.
PAL (Phase Alternate Line. See CCIR) - Colour TV system used in the UK.
Pan - Side-to-side movement of a camera (on a horizontal axis).
Partition - Segmented section of a security system.
Passive - A non powered element of a system.
Password - A special word, code or symbol that must be presented to
the computer system to gain access to its resources. It identifies the
user to the computer system.
Patch Panel - A panel where circuits are terminated and facilities
provided for interconnecting between circuits by means of jacks and
plugs.
PCI (Peripheral Component Interconnect) Bus - PCI Local Bus is a
high-performance bus that provides a processor-independent data
path between the CPU and high-speed peripherals. PCI is a robust
interconnect mechanism designed specifically to accommodate multiple
high performance peripherals for graphics, full-motion video, SCSI and
LANs.
PCMCIA (Personal Computer Memory Card International Association) -
A non-profit trade association founded in 1989 to standardise a method
for connecting peripherals to PCs. PCMCIA created a 16- bit socket that’s
“Plug-and-Play” compatible and can be automatically configured by a
software driver called PCMCIA Card Services.
Peak White Inverter (Eclipser) - An electronic circuit that turns any
white part of a video signal, over a preset level, to black. If installed in
the auto iris video line it decreases the contrast of one picture, bringing
out detail otherwise lost in shadow.
Pedestal - The portion of a video signal between the sync pulses and
the black level.
Peer-to-Peer - Communications in which both sides have equal
responsibility for initiating, maintaining and terminating the session.
Phase Adjustable (see Line Lock) - The ability to delay the line locking
process, so as to align cameras fed from AC voltages on different
phases.
Photocell - Automatically switches on the infra-red lights when light
levels fall to a preset level.
Pico - Order of magnitude; 10–12.
PIN - Personal Identification Number.
PING (Packet InterNet Groper) - A utility used to determine if a TCP/IP
device is available and responsive on a network or at an Internet site.
PIR (Passive Infra-Red Receiver) - Movement/motion detector.
Pixel (Picture Element) - The smallest cell or area of a CCD chip capable
of displaying detail on a screen. The greater the number of pixels, the
higher the resolution.
Plasma - A type of flat screen display.
PoE (Power over Ethernet) - Provides power to a network device via the
same cable as used for the network connection.
Port - That portion of a computer through which a peripheral device
may communicate.
P-P (Peak-to-Peak) - The voltage of a signal measured between its most
positive and negative points. CCIR standard video is 1 volt P-P.