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18. Glossary
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<Dual Stream: <
Dual Stream> is a technology used to record high resolution video locally while
transmitting a lower resolution stream over the network. The two streams are generated by the
NVR, with the <Main Stream> having a maximum resolution of <4CIF> and the <Sub-stream>
having a maximum resolution of <CIF>.
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HDD:
Acronym for <Hard Disk Drive>. A storage medium which stores digitally encoded data on
platters with magnetic surfaces.
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<DHCP>:
<Dynamic Host Configuration Protocol (DHCP)> is a network application protocol used by
devices (<DHCP Clients>) to obtain configuration information for operation in an <Internet
Protocol> network.
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<HTTP>:
Acronym for <Hypertext Transfer Protocol>. A protocol to transfer a hypertext request
and information between servers and browsers over a network.
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<DDNS>: <
Dynamic DNS> is a method, protocol or network service that provides the capability for
a networked device such as a router or a computer system using the <Internet Protocol Suite>, to
notify a domain name server to change, in <Real-time> (<Ad-hoc>) the active <DNS> configuration
of its configured hostnames, addresses or other information stored in the <DNS>.
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<Hybrid NVR>:
A <Hybrid NVR> is a combination of a DVR and an NVR.
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<NTP>:
Acronym for <Network Time Protocol>. A protocol designed to synchronize the clocks of
computers over a network.
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<NTSC>:
Acronym for <National Television System Committee>. <NTSC> is an analog television
standard used in such countries as the United States and Japan. Each frame of an <NTSC> signal
contains 525 scan lines at 60Hz.
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NVR:
Acronym for <Network Video Recorder>. An NVR can be a PC-based or embedded system
used for centralized management and storage for IP cameras, IP Domes and other NVRs.
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<PAL>:
Acronym for <Phase Alternating Line>. <PAL> is also another video standard used in
broadcast television systems in large parts of the world. <PAL> signal contains 625 scan lines at
50Hz.
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<PTZ>:
Acronym for <Pan>, <Tilt>, <Zoom>. <PTZ Cameras> are motor driven systems that allow
the camera to pan left and right, tilt up and down and zoom in and out.
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USB:
Acronym for <Universal Serial Bus>. USB is a plug-and-play serial bus standard to interface
devices to a host computer.
