Glossary
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f
Used to indicate the range of focal length, such as f 2.4~24mm. See focal length.
F
Used to indicate the size of IRIS. See IRIS.
Factory default settings
The original setting for a device when it was first delivered from the factory.
Sometimes, it is necessary to completely reset the settings changed by the user to factory default settings.
FCC
CFederal Communications Commission; is responsible for administering the television and radio airwaves, satellite and cable transmissions, and telegraph communications.
Firewall
A program or hardware that prevents unauthorized access to a network or an individual computer.
Fixed iris
Fixed IRIS lens is one kind of iris and with fixed size IRIS.
Flash ROM
A type of read-only memory, which can be erased and reprogrammed or by loading new software.
Focal length
The distance between a lens and its focal point. Usually expressed in millimeters, smaller focal lengths result in wider fields-of-view.
Format
For image process, referring to the type of computer format in which the electronic image has been saved, i.e., JPEG, TIFF, etc.
Frame
It is a complete video image. A video frame is made up of two interlaced fields of either 525 lines (NTSC) or 625 lines (PAL).
Frame Rate
The rate at which video frames are displayed on a monitor per second. Frame rate for PAL is 25 fps, and frame rate for NTSC is 30 fps.
FTP
File Transfer Protocol: A TCP/IP protocol specifying the transfer of text or binary files across the network.
Full-duplex
A system that allows both directions transmission at once. It requires dual communication paths between two devices.
