19.3 Glossary
Dual Stream: Dual stream is a technology used to record high resolution video locally while
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transmitting a lower resolution stream over the network. The two streams are generated by
the device, with the main stream having a maximum resolution of 4CIF and the sub-stream
having a maximum resolution of CIF.
HDD: Acronym for Hard Disk Drive. A storage medium which stores digitally encoded data on
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platters with magnetic surfaces.
DHCP: Dynamic Host Configuration Protocol (DHCP) is a network application protocol used
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by devices (DHCP clients) to obtain configuration information for operation in an Internet
Protocol network.
HTTP: Acronym for Hypertext Transfer Protocol. A protocol to transfer hypertext request
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and information between servers and browsers over a network
DDNS: Dynamic DNS is a method, protocol, or network service that provides the capability
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for a networked device, such as a router or 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 DNS.
PPPoE: Stands for "Point-to-Point Protocol over Ethernet." PPPoE is a network configuration
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used for establishing a PPP connection over an Ethernet protocol.
Hybrid device: A hybrid device is a combination of a DVR and device.
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NTP: Acronym for Network Time Protocol. A protocol designed to synchronize the clocks of
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computers over a network.
NTSC: Acronym for National Television System Committee. NTSC is an analog television
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standard used in such countries as the United States and Japan. Each frame of an NTSC
signal contains 525 scan lines at 60Hz.
Device: Acronym for Network Video Recorder. A device can be a PC-based or embedded
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system used for centralized management and storage for IP cameras, IP Domes and other
devices.
PAL: Acronym for Phase Alternating Line. PAL is also another video standard used in
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broadcast televisions systems in large parts of the world. PAL signal contains 625 scan lines
at 50Hz.
PTZ: Acronym for Pan, Tilt, Zoom. PTZ cameras are motor driven systems that allow the
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camera to pan left and right, tilt up and down and zoom in and out.
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