Axis 207MW Manuale Utente

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AXIS 207W/AXIS 207MW - Glossary of Terms
images (VOP's) in the GOV structure. See also GOV and 
VOP.
GOV structure - The GOV structure describes the 
composition of an MPEG-4 video stream, as regards the type 
of images (I-VOP's or P-VOP's) included in the stream, and 
their internal order. See also GOV and VOP.
Half-duplex - See Full-duplex
HTML (Hypertext Markup Language) - HTML is the set of 
"markup" symbols or codes inserted in a file intended for 
display in web browser. The markup tells the browser how 
to display the page's words and images for the user.
HTTP (Hypertext Transfer Protocol) - HTTP is the set of 
rules for exchanging files (text, graphic images, sound, 
video, and other multimedia files) on the web. The HTTP 
protocol runs on top of the TCP/IP suite of protocols.
Hub - A (network) 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.
IEEE 802.11 - A family of standards for wireless LANs. 
802.11b supports a data rate of 11 Mbit/s on the 2.4 GHz 
band, 802.11a allows up to 54 Mbit/s on the 5 GHz band, 
and 802.11g allows up to 54 Mbit/s on the 2.4 GHz band.
Image compression - Image compression minimizes the file 
size (in bytes) of an image. Two of the most common 
compressed image formats are JPEG and GIF.
Interlacing - Interlaced video is video captured at 50 
pictures (known as fields) per second, of which every 2 
consecutive fields (at half height) are then combined into 1 
frame. Interlacing was developed many years ago for the 
analog TV world and is still used widely today. It provides 
good  results when viewing motion in standard TV pictures, 
although there is always some degree of distortion in the 
image.
To view interlaced video on e.g. a computer monitor, the 
video must first be de-interlaced, to produce progressive 
video, which consists of complete images, one after the 
other, at 25 frames per second. See also Progressive scan
IP (Internet Protocol) - The Internet Protocol is a method 
for transmitting data over a network. Data to be sent is 
divided into individual and completely independent 
"packets." Each computer (or host) on the Internet has at 
least one address that uniquely identifies it from all others, 
and each data packet contains both the sender's address and 
the receiver's address. 
The Internet Protocol ensures that the data packets all arrive 
at the intended address. As IP is a connectionless protocol, 
which means that there is no established connection 
between the communication end-points, packets can be sent 
via different routes and do not need to arrive at the 
destination in the correct order. 
Once the data packets have arrived at the correct 
destination, another protocol -  Transmission Control 
Protocol (TCP) - puts them in the right order. See also TCP.
Internet Protocol version 6 - IPv6 follows IPv4 (see IP 
(Internet Protocol) 
above) as the second version of the 
protocol to be formally adopted for general use. IPv6 is 
intended to provide further IP addresses for the increasing 
number of networked devices, and supports 3.4x10
38
 IP 
addresses.
IP Address - An IP address is simply an address on an IP 
network used by a computer/device connected to that 
network. IP addresses allow all the connected 
computers/devices to find each other and to pass data back 
and forth. 
To avoid conflicts, each IP address on any given network 
must be unique. An IP address can be assigned as fixed, so 
that it does not change, or it can be assigned dynamically 
(and automatically) by DHCP. 
An IP address consists of four groups (or quads) of decimal 
digits separated by periods, e.g. 130.5.5.25. Different parts 
of the address represent different things. Some part will 
represent the network number or address, and some other 
part will represent the local machine address. 
See also IP (Internet Protocol).
I-VOP - See VOP.
JPEG (Joint Photographic Experts Group) - Together with 
the GIF file format, JPEG is an image file type commonly 
used on the web. A JPEG image is a bitmap, and usually has 
the file suffix '.jpg' or ".jpeg." When creating a JPEG image, 
it is possible to configure the level of compression to use. As 
the lowest compression (i.e. the highest quality) results in 
the largest file, there is a trade-off between image quality 
and file size. 
kbit/s (kilobits per second) - A measure of the bit rate, i.e. 
the rate at which bits are passing a given point. See also Bit 
rate
.
LAN (Local Area Network) - A LAN is a group of 
computers and associated devices that typically share 
common resources within a limited geographical area.
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.
MAC address (Media Access Control address) - A MAC 
address is a unique identifier associated with a piece of 
networking equipment, or more specifically, with its 
interface with the network. For example, the network card 
in a computer has its own MAC address. 
Manual iris - This is the opposite to an autoiris, i.e. the 
camera iris must be adjusted manually to regulate the 
amount of light allowed to reach the image sensor.
Mbit/s (Megabits per second) - A measure of the bit rate, 
i.e. the rate at which bits are passing a given point.