User manual

DS1093-039 90
18 GLOSSARY
• 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 4CIF and the sub-stream having a maximum resolution of QCIF.
• 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.
• HDD: Acronym for Hard Disk Drive. A storage medium which stores digitally encoded data on platters with
magnetic surfaces.
• 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.
• HTTP: Acronym for Hypertext Transfer Protocol. A protocol to transfer hypertext request and information
between servers and browsers over a network
• 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.
• 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.
• NTP: Acronym for Network Time Protocol. A protocol designed to synchronize the clocks of computers over a
network.
• 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.
• 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.
• 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.
• USB: Acronym for Universal Serial Bus. USB is a plug-and-play serial bus standard to interface devices to a
host computer.