Network Video Recorder User Manual
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Chapter 18 Appendix
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 device, 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 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 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.
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PPPoE: Stands for "Point-to-Point Protocol over Ethernet." PPPoE is a network configuration
used for establishing a PPP connection over an Ethernet protocol.
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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
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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Device: Acronym for Network Video Recorder. A device can be a PC-based or embedded
system used for centralized management and storage for IP cameras, IP Domes and other
devices.
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PAL: Acronym for Phase Alternating Line. PAL is also another video standard used in
broadcast televisions 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.
