- Axis User's Manual Network Camera 207/207W

50
AXIS 207/207W - Glossary of Terms
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 - MPEG-2 is the designation for a group of audio
and video coding standards, and is typically used to encode
audio and video for broadcast signals, including digital
satellite and Cable TV. MPEG-2, with some modifications, is
also the coding format used by standard commercial DVD
movies.
MPEG-4 - MPEG-4 is 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.
Most of the features included in MPEG-4 are left to
individual developers to decide whether to implement them
or not. This means that there are probably no complete
implementations of the entire MPEG-4 set of standards. To
deal with this, the standard includes the concept of
"profiles" and "levels", allowing a specific set of capabilities
to be defined in a manner appropriate for a subset of
applications.
Multicast - Bandwidth-conserving technology that reduces
bandwidth usage by simultaneously delivering a single
stream of information to multiple network recipients.
Multiplexer - A multiplexer is a high-speed switch that
provides full-screen images from up to 16 analog cameras.
Multiplexers can playback everything that happened on any
one camera with no interference from the other cameras on
the system.
Network connectivity - The physical (wired or wireless)
and logical (protocol) connection of a computer network or
an individual device to a network, such as the Internet or a
LAN.
NTSC (National Television System Committee) - NTSC is
the television and video standard in the United States. NTSC
delivers 525 lines at 60 half-frames/second.
OEM (Original Equipment Manufacturer) - This is a
designation for companies that manufacture equipment
which is then marketed and sold to other companies under
their own names.
PAL (Phase Alternating Line) - PAL is the dominant
television standard in Europe. PAL delivers 625 lines at 50
half-frames/second.
PEM (Privacy Enhanced Mail) - An early standard for
securing electronic mail. The PEM-format is often used for
representing an HTTPS certificate or certificate request.
Ping - Ping is a basic network program used diagnostically
to check the status of a network host or device. Ping can be
used to see if a particular network address (IP address or
host name) is occupied or not, or if the host at that address
is responding normally. Ping can be run from e.g. the
Windows Command prompt or the command line in Unix.
Pixel - A pixel is one of the many tiny dots that make up a
digital image. The colour and intensity of each pixel
represents a tiny area of the complete image.
PoE (Power over Ethernet) - Power over Ethernet provides
power to a network device via the same cable as used for
the network connection. This is very useful for
IP-Surveillance and remote monitoring applications in
places where it may be too impractical or expensive to
power the device from a power outlet.
PPP (Point-to-Point Protocol) - A protocol that uses a
serial interface for communication between two network
devices. For example, a PC connected by a phone line to a
server.
PPTP (Point-to-Point Tunnelling Protocol) - A protocol
(set of communication rules) that allows corporations to
extend their own corporate network through private
"tunnels" over the public Internet. In this way a corporation
can effectively use a WAN (Wide Area Network) as a large
single LAN (Local Area Network). This kind of
interconnection is known as a virtual private network
(VPN).
Pre/post alarm images - The images from immediately
before and after an alarm. These images are stored in a
buffer for later retrieval.
Progressive scan - Progressive scan, as opposed to
interlaced video, scans the entire picture, line by line every
sixteenth of a second. In other words, captured images are
not split into separate fields as in interlaced scanning.
Computer monitors do not need interlace to show the
picture on the screen, but instead show them progressively,
on one line at a time in perfect order, i.e. 1, 2, 3, 4, 5, 6, 7
etc., so there is virtually no "flickering" effect. In a
surveillance application, this can be critical when viewing
detail within a moving image, such as a person running. A
high-quality monitor is required to get the best from
progressive scan. See also Interlacing.
Protocol - A special set of rules governing how two entities
will communicate. Protocols are found at many levels of
communication, and there are hardware protocols and
software protocols.
Proxy server - In an organisation that uses the Internet, a
proxy server acts as an intermediary between a workstation
user and the Internet. This provides security, administrative
control, and a caching service. Any proxy server associated
with a gateway server, or part of a gateway server,
effectively separates the organisation’s network from the
outside network and the local firewall. It is the firewall
server that protects the network against outside intrusion.
A proxy server receives requests for Internet services (such
as web page requests) from many users. If the proxy server
is also a cache server, it looks in its local cache of
previously downloaded web pages. If it finds the page, it is