 |
The introduction of IP-Based security products has brought about
a new, exciting opportunity for both the installers and the
end-user.
This new technology can be intimidating to somebody who is
accustomed to traditional security equipment as it has brought with
it its own language, terms and definitions.
|
In order to 'de-mystify' new technology and to provide
background information, we have compiled a glossary of key terms
and abbreviations which can act as your guide to all of those
questions which you required an answer for but were too scared to
ask…
3G - 3G refers to
the third generation of developments in wireless technology,
especially mobile communications. A 3G system should be operational
anytime, anywhere, and security systems utilising 3G technology are
'Network Edge Appliances' with embedded software, and therefore no
PCs are required.
4CIF - Four times Common
Intermediate Format; a format of colour images, 704 x 576 pixels
(PAL) and 704 x 480 pixels (NTSC).
DCIF - Double times Common
Intermediate Format; a format of colour images, 528 x 384 pixels
(PAL) and 528 x 320 pixels (NTSC)
CIF - Common Intermediate Format; a format of
colour images, 352 x 288 pixels (PAL) and 352 x 320 pixels
(NTSC)
QCIF - Quarter Common Intermediate Format; a
format of colour images, 176 x 144 pixels (PAL) and 176 x 120
pixels (NTSC)
Explanation -
DCIF can solve a number of resolution problems with CIF images
and large-stream data, providing a higher quality of
image.
ANPR - Automatic Number Plate Recognition. ANPR
is now being used extensively by government national security
departments in their fight against global terrorism, to track
suspect vehicles and provide a coordinated response at cross border
points.
Bandwidth - Used
as an indication of the capacity of the link used to transmit data.
This is measured in frequency (Hz or cycles per second). Most
commonly, bandwidth is the term used to signify the amount of data
that can be carried from one point to another in a given time
period, and therefore in general terms is the speed of transfer.
Measurements are generally in MHz or GHz.
Bitmap - Bitmap
describes a rectangular 'map' of bits (pixels). Typical Bitmaps are
JPEGs or GIFs. Because the co-ordinates, bits or pixels of the
'map' are defined, or fixed, this means that the image cannot be
easily rescaled without losing definition.
Bluetooth -
Standard for wireless communication and transfer of data between
devices, i.e mobile phone, laptop.
Broadcast - A
message on a bus intended for all devices where no reply is
necessary. Broadcast should not be confused with unicast a
transmission to a specific receiver (like most e-mail messages),
multicast a transmission to multiple specific receivers, or
anycast.
BS8418 - The
British Standard for Installation and remote monitoring of detector
activated CCTV systems. Currently, this standard is mandatory only
under the auspices of the Association of Chief Police Officers
(ACPO- see above) in England, Wales and Northern Ireland.
Bus - A bus is a
data route shared by many devices with one or more conductors for
transmitting signals, data or power. Like on a bus route signals
are the passengers either picked up or dropped off at designated
stops (devices).
Coaxial Cable - Cabling used in traditional
analogue CCTV systems.
Codec - Converts analogue to digital
streams.
Collision - The situation when two or more LAN
nodes attempt to transmit
at the same time.
Compression - Compression is the reduction in
size of data in order to
save space or transmission time. Graphic image file formats are
compressed in several different ways: the most common being JPEG or
GIF. The JPEG method is more often used for detailed photographs,
for instance, while the GIF method is commonly used for more simple
images.
Digital - Digital technology basically
comprises the processing of data in the form of 1s and 0s (binary
code). Information is stored, generated, processed and transmitted
in this format. Prior to the electronic revolution within the
security industry, electronic transmission utilised traditional
analogue methods - the transfer of data as electronic signals of
varying frequency or amplitude that are added to carrier waves of a
given frequency.
DHCP - Dynamic Host Configuration Protocol is
the method for allowing network administrators to assign IP
addresses to system components such as cameras, servers,
workstations.
DNS - Domain name system; for translating
computer hostnames to IP addresses in a user friendly way
Encoder - A circuit, which changes a given
signal into a coded combination for purposes of optimum
transmission of the signal.
Ethernet - Name of one of the most widely used
LAN technologies. Ethernet LANs can utilise coaxial cable, twisted
pair wires or also wireless.
Firewall - Acting as a filter, a firewall is a
set of programs in a server which prevents unauthorised access to
resources of its private network from users from other networks.
Typically a firewall is utilised to examine and, if needed,
stop
unwanted communications from getting through.
Gateway - A device to connect two different
networks which translates the different protocols.
GIF - Graphics Interchange Format. Compression
method for images.
GPRS - General Packet Radio Service. GPRS is a
'high data rate' communication service, widely used for interactive
applications such as video conferencing. Utilised on new mobile
phones and computers, the service works on the theory that
continuous connection to the Internet and shared use of
communication channels actually costs less than dedicated
connections for only one user at a time.
H.264 - A kind of video compression standard,
also called MPEG- 4 (Part 10)
HD - High
Definition
HTTP - Hypertext Transfer Protocol
Hub - A hub is used to connect multiple devices
to the network. The hub transmits all data to all devices connected
to it, whereas a switch will only transmit the data to the device
it is specifically intended for.
Infrared - Infrared images are those at a
longer wavelength than visual light.
Infrared images cannot be seen by the naked eye, but can be seen by
cameras. Therefore some cameras are fitted with IR filters in order
that the images produced are not distorted.
IP Address - Each appliance (for instance a
networked camera, a computer, server, workstation) utilising the
Internet has at least one unique IP address which is used to
differentiate and sort it from all other devices on the Internet.
One simple comparison is to think of the IP address as a postcode-
data can be directed to
and from appliances by the utilising of this postcode. IP addresses
can be static or dynamic.
ISDN - Integrated Services Digital Network
(ISDN) is a set of standards for transmitting signals
digitally over ordinary telephone copper wire as well as over other
media. Connections to the Internet over ISDN have speeds of up to
128
kilobites per second compared with the maximum of 56 Jbps rate of
a
modem connection.
JPEG - Abbreviation standing for Joint
Photographic Experts Group. A compression standard for graphic
images. Such images use the .JPG file extension.
LAN - Local Area Network. A data communications
system confined to a limited geographic area typically about 3km
with high data rates. Almost all businesses and organisations,
irrespective of their size and number of employees, now
have an IP network infrastructure in place. This can range in size
from a
few computers in a building, to tens of thousands of computers in
many
buildings, often in different locations, all linked together as a
single
system. With this type of network in place, why then design and
install an
additional separate, expensive infrastructure for your security
system?
Advances in technology have made it possible to monitor and control
your security system on your existing LAN/WAN. Access control,
video surveillance, intruder alarms and building management
systems can all be networked - providing you
with a fully integrated system
MAC - Media Access Control (IEEE 802) address
is the unique reference number allocated to a networked device, for
example the network card in a computer would have its own MAC
address.
M-JPEG - Motion
Picture Experts Group. A standard that treats each field of a
moving picture as a still image where the compression is applied to
each individual image.
Monitoring - The
basic idea of event monitoring is simply to inform a key holder
and/or local police, that the alarm system has been activated.
Modem - A modem
translates outgoing digital signals from a device to analogue
signals for a conventional telephone line and vice versa.
MPEG - The Moving
Picture Experts Group develops standards for digital video and
audio compression. It operates under the auspices of the
International Organization for Standardization (ISO). The MPEG
standards are an evolving series, each designed for a different
purpose.
MPEG-2 -
Compression technique typically used to encode audio and video for
broadcast signals, including digital satellite and Cable TV.
M-PEG-4 - Audio
and Video streaming and compression methods, generally utilised for
web-streamed or broadcast video.
Multiplexer - A
switch that provides full-screen images from multiple cameras (up
to 16) incorporating playback and recording at no detriment to
other cameras on the system.
Multicast -
Multicast is a fairly self-explanatory term for the method of
communication between a single sender and multiple receivers on a
network, for instance an electronic mailshot.
NAT - Included as
a part of a router, NAT (Network Address Translation) is the
translation of an IP address from one network to a different IP
address known within another network and assists with network
security protocol.
Network - A communication path containing an
interconnected group of nodes or stations. Networks are often
characterized by their communication method, for instance, an IP
network and carries data in a variety of forms.
NFS - Network File System
Node - A point of interconnection to a network
with the capability to process and forward signals and
communications.
OSD - On screen display
PPP - Point to point protocol
Protocol - A
formal set of conventions governing the formatting, control
procedures and relative timing of message exchange between two
communicating systems.
Proxy Server - The proxy server is the
'middle-man' in communications between, say, a single workstation
and the internet to ensure security. The 'bouncer' of the IT world,
the proxy server is usually associated with the gateway and the
firewall.
QoS - Quality of
Service. Method of analysing transmission rates, error rates etc of
internet service provided in order to ensure that measurement can
be taken, and improvements made if necessary.
RF - Radio
Frequency (RF) refers to the current which is routed through an
antenna, an electromagnetic field, a 'radio wave' is generated.
When tuning into the radio for example, the signal for broadcasts
is the frequency at which the radio wave is sent.
Router - A router
is basically a linking device, or embedded software between
separate network segments which assigns the route that data should
be forwarded to and what its destination on the network will
be.
RTP - Real-time Transport Protocol
Static/ Dynamic IP
Addresses - Although the earlier description of IP
addresses gives the impression that they are assigned on a static,
permanent basis, this was simply an introduction. Once you have
your head around the idea of IP addresses however, it is not too
much of a leap to then understand dynamic IP addresses. Many
corporate networks and online services economize on the number of
IP addresses they use by sharing a pool of IP addresses among a
large number of users.
Subnet Mask - Subnet is an abbreviation of
subnetwork. A subnet is typically a geographically separate part of
your network, for example a remote office location, which still
utilises the same network, or LAN.A Subnet mask is simply the
screen of numbers which tells the router which numbers in the 32
bit address are to be looked at. In this case, the router will look
at these numbers as represented by 1s and 0s, with 1 being those
numbers which the router should 'look underneath' and 0s being
numbers in this address which can be ignired to save processing
time.
TCP - Transmission control protocol
is used along with IP in the transmission of data
between networked devices. If IP is the delivery vehicle, TCP acts
as the 'delivery driver' whose responsibility it is to re-assemble
the component parts of the data being transmitted, once destination
is reached.
Terminal Adaptor - Acts as a replacement for a
modem. A Terminal Adaptor integrates ISDN channels with existing
network standards.
URL - Uniform Resource Locator
USB - Universal Serial Bus
VGA - Stands for a kind of resolution, 640 x
480 pixels.
VPN - The Virtual
Private Network creates a secure "tunnel" in which only devices
with the correct "key" will be able to enter. One common use for
VPN is for connecting a remote computer to the corporate network,
via e.g. a direct phone line or via the Internet.
Virus - A virus is
a program or programming code which can enter your network by being
downloaded via an external source, for instance a CD, or email
attachment. The virus then can act in a variety of ways, many of
which are harmful to the network or computer itself and can
effectively 'contaminate' existing files.
VoIP - Voice over
IP the delivery of telephone conversations via 'packets' of data
rather than through the traditional copper wire telephone network.
Because it does not rely on traditional telephone networks it is
therefore more cost effective as it avoids the usual tolls placed
on phone lines by telecommunications service providers.
VMD - Video Motion
Detection, or Intelligent Video is one of the next generation of
surveillance tools. Either embedded in the hardware or software, it
can automatically track and identify objects, for instance left
baggage at airports.
WAN - Wide Area
Network. Similar to a LAN however on a much larger actual
geographical scale- i.e international networks for large
multi-national organisations.
Wavelet - Wavelet
is a mathematical function useful in data compression. Compression
is greater than in other methods such as JPEG because it analyzes
an image and converts it into a set of mathematical expressions
that can then be decoded by the receiver. A wavelet-compressed
image file is often given a name suffix of "WIF."
Wireless - In the
security industry, 'wireless' is a fairly self-explanatory term.
Instead of the communication path being via some form of wire or
cable, the signal is instead carried via electromagnetic waves,
often saving on the labour costs and disruption associated with
cabling.
WWW - World Wide Web. Web inventor Tim
Berners-Lee of the World Wide Web Consortium (W3C): describes www
as: " the universe of network-accessible information, an embodiment
of human knowledge."