Digital Video Recorder User Manual
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Chapter 15 Appendix
15.1 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 DVR, with the main
stream having a maximum resolution of 1080P and the sub-stream having a maximum resolution of CIF.
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DVR:
Acronym for Digital Video Recorder. A DVR is device that is able to accept video signals from
analog cameras, compress the signal and store it on its hard drives.
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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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PPPoE:
PPPoE, Point-to-Point Protocol over Ethernet, is a network protocol for encapsulating
Point-to-Point Protocol (PPP) frames inside Ethernet frames. It is used mainly with ADSL services where
individual users connect to the ADSL transceiver (modem) over Ethernet and in plain Metro Ethernet
networks.
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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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Hybrid DVR:
A hybrid DVR is a combination of a DVR and 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 DVRs.
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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.
