ActiveX - A set of technologies created by Microsoft that
enables interactive content on Web sites. Our in-house developed
applications may sometimes require download of a small ActiveX program.
This is entirely safe.
ADSL (Asynchronous Digital Subscriber Line) - A telephone
line with uneven transmission rates, half the transmission (upstream) can
attain speeds of up to 640Kbps, the other half (downstream) can acheive
2,048Kbps or greater.
Applet - A small Java program that can be embedded in
an HTML, or web page. Applets differ from full-fledged Java applications
in that they are not allowed to access certain resources on the local computer,
such as files and serial devices (modems, printers, etc.), and are prohibited
from communicating with most other computers across a network. The common
rule is that an applet can only make an Internet connection to the computer
from which the applet was sent. NW Systems Group Limited uses Java applets as part of
its set of tools.
Bandwidth - The data transfer capacity available on
a given line to the internet. Typically the downstream data transfer
capacity.
Built-in Motion Detection - Cameras equipped with built-in
motion detection can identify any motion or change in live video based
on user-set sensitivity levels. Advanced cameras can be set to e-mail
images or video showing the motion or change detected.
CCTV (Closed Circuit Television) - Despite its name, CCTV
is not television! It does not broadcast TV signals but transmits them
over a closed circuit through electrically conducting cable or wireless
transmitter and reciever.
CCD - Charge-Coupled Device - Electronic memory in which
metal oxide semiconductors are arranged so the charge from one semiconductor
is the input of the next semiconductor. CCDs can be charged by light or
electricity. One use is for storing images in digital cameras, video cameras,
and optical scanners. Network Cameras that employ CCD technology typically
cost more than analogue cameras.
Data compression - A process that reduces the file size
for processing, storage, transmission, and display. Compression may be
lossless (e.g., CCITT) or lossy (JPEG). The quality of the image may be
affected by the compression techniques used and the level of compression
applied.
DNS - Domain Name System - The system for
translating web addresses to IP addresses. For a device to contact a web
or FTP server using its domain name it must first obtain a corresponding
IP address from a local DNS server. ISPs will provide two DNS servers,
a primary and a secondary.
Ethernet - A very common method of networking computers
in a LAN. Ethernet will handle about 10,000,000 bits per second and can
be used with almost any kind of computer.
Embedded Operating System - Network IP Cameras that use
an embedded operating system, such as Linux, operate as both cameras and
computers. Cameras with embedded operating systems can perform advanced
functions, such as the ability to send images to a web site via FTP; simultaneous
access by multiple users and e-mail notification.
Firewall - A combination hardware and software buffer
that many companies or organizations have in place between their internal
networks and the Internet. A firewall allows only specific kinds of messages
from theInternet to flow in and out of the internal network. This protects
the internal network from intruders or hackers who might try to use the
Internet to break into those systems.
FTP - File Transfer Protocol - Network cameras equipped
with an embedded operating system, such as Linux, can use FTP to send images
to a web site.
H.263 - A standard video-conferencing codec. As such,
it is optimized for low data rates and relatively low motion. H.263 is
an advancement of the H.261 standard, mainly. It was used as a starting
point for the development of MPEG (which is optimized for higher datarates.)
HTTP (HyperText Transfer Protocol) - The protocol for
moving hypertext files across the Internet. Requires a HTTP client program
on one end, and an HTTP server program on the other end. HTTP is the most
important protocol used in the World Wide Web .
ISDN (Integrated Services Digital Network) - Digital telephony
scheme that allows a user to connect to the Internet over standard phone
lines at speeds higher than a 56K modem allows.
IP (Internet Protocol) - the most basic protocol to communicate
on the Internet. An IP number is a numerical address consisting of four
numbers seperated by full stops. Each IP address uniquely identifies a
certain computer on the Internet. Domain names are used to make using them
easier.
IP Storage - A generic term for a method of storing images
and video on hard disc recorders connected to a LAN or the Internet.
Java - A computer programming language invented by Sun
Microsystems. Using Java, Web developers create small programs called "applets" that
allow Web pages to include animations, calculators, scrolling text, sound
effects and games. See also Applet
JavaScript - Popular client-side scripting language originally developed
by Netscape. Commonly used to make static HTML documents more interactive.
Despite its name, JavaScript is not related to Java.
JPEG - Joint Photographic Experts Group. Together with
GIF, JPEG (or JPG) is one of the two commonly used image formats on the
Web. JPEG format is best suited to photographic images, and, of course,
webcams!
Local area Network (LAN) - A computer interconnection
network for limited connection distances, like those of an office environment.
Leased Line - A leased line is a transmission line reserved
by a communications carrier for the private use of a customer. Examples
of leased-line services are 56Kbits/sec or T-1 lines.
Linux - Linux is an open source operating system within
the Unix family. Because of its robustness and availability, Linux has
won popularity in the open source community and among commercial application
developers. Camvista uses the flexibility and power of Linux to drive its
tools and applications.
Mpeg - The acronym for Moving Pictures Expert Group, MPEG
is an international standard for video compression and desktop movie presentation.
A special viewing application is needed to run MPEG files on your computer.
Multiplexer - These units are high-speed switches that
provide full-screen images from up to 16 cameras. Multiplexers can playback
everything that happened on any one camera without interference from the
other cameras on the system.
Network camera - Cameras are attached through an Ethernet
connection (or router) and power source, so you don't need a computer at
each location you want monitored. Each camera has a built-in web server
with IP address. To view the images on a PC, simply open a graphics-capable
Web browser and type in the cameras specified, password optional Internet
address.
PING - Loosely translated, ping means 'to get the attention
of' or 'to check for the presence of' another party online. Ping operates
by sending a data packet to a designated address and waiting for a response.
The computer acronym was contrived to match the submariners' term for the
sound of a returned sonar pulse.
Professional Webcam System - A business strength webcam
designed to offer features useful for business use and built to be far
more reliable than ordinary home webcams.
PSTN - Public Switched Telephone Network. PSTN is a name
for the public fixed telephone network
PTZ (Pan, Tilt & Zoom) - A term to define a controllable
camera. Describes the three directions in which control can be made - pan
(left to right), tilt (up and down) and zoom (in and out).
Remote access - A broad term meaning the ability to log
on to a network or resource from a distant location. Generally, this requires
a computer, a network connection and remote-access software to allow the
computer to connect into the network.
Remote Monitoring - The process of viewing and/or recording live images and video footage from a remote location, typically for surveillance purposes.
Resolution - A measure of how clear and crisp an image
appears on a monitor. As each piece of CCTV equipment included within a
system contributes to the overall image quality, the resultant image can
only be as clear as the piece of equipment with the lowest resolution.
If you are using a high-resolution monitor together with a low-resolution
camera, the monitor can only display low-resolution images. This observation
becomes increasingly important when using the system for webcams and recording.
Router - A special-purpose computer or software package
that handles the connection between 2 or more networks. Routers spend all
their time looking at the destination addresses of the packets passing
through them and deciding which route to send them on.
TCP/IP - the collection of "protocols" underlying the
functioning of the Internet. Each computer connected to the Internet is
identified by a unique IP Address.
Video Server - Generally, a device which accepts analog
video connections and outputs them as digital video streams. Many video
servers can deliver video in a number of ways, including as a video stream
or as individually uploaded images.
Video Switcher - Sequentially displays full screen images,
one camera after another typically at 3 to 5 seconds intervals. While the
image source from one camera is displayed on screen the other camera sources
are not being recorded.
Webcam - Generally, a digital camera designed to take
digital photographs and transmit them over the internet. Most webcams require
additional PC software to operate. Traditionally, these inexpensive lower-end
cameras are for home use only. Businesses considering a webcam presence
should opt for a more robust and reliable network camera option.
Webcam (professional) - Professional webcams use industry
standard CCTV or video equipment to present high quality images and video
for distribution via the Internet. NW Systems Group Limited offer only these professional
systems.
Wireless (WiFi) - A local area network that uses high
frequency radio signals to transmit and receive data over distances of
a few hundred feet; uses ethernet protocol.
Glossary of Terms
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