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Glossary
NTSC (National Television Standards Committee) A standard of specifications for
television transmission in the U.S., Canada, Japan, Central American, and half of South
America. The North American system uses interlaced scans and 525 horizontal lines per
frame at 30 frames per second.
PAL (Phase Alternate Line) A standard of specifications for television transmission for
color TV signals used in West Germany, England, Holland, Australia, and several other
countries. It uses an interlaced format with 625 lines per frame at 25 frames per second.
PoE (Power over Ethernet) A method of powering Ethernet-connected devices via the
Ethernet cabling as defined in the IEEE 802.3af standard.
Shutter Speed The speed at which the charge is read out from the CCD chip. Adjusts the
light sensitivity of the camera. A faster (briefer) shutter speed can arrest the motion of a fast
moving object (reduce image blur), rendering it sharp. Fast shutter speeds allow less light
to all on the CCD and can darken the image. For fast shutter speeds, ensure there is
adequate lighting. Usually selected using DIP switches on the side of the camera.
Subnet Mask A number used to identify a subnetwork so that an IP address can be shared
on a LAN.
True Day/Night The incorporation of a moving mechanical IR filter within the camera
ensures true 24 hour surveillance, providing high quality color images during the day and
similar quality black & white images at night when used with IR lighting.
UPS (Uninterruptible Power Supply) These are power supplies used in the majority of
high security systems, whose purpose is to back up the system when the main power fails.