Beward N35110, Руководство пользователя, Страница: 71 / 76

Appendix
N6603 Installation User Manual
70
Ethernet is the most widely installed local area network technology. An Ethernet LAN
typically uses special grades of twisted pair wires. The most commonly installed Ethernet systems
are 10BASE-T and 100BASE-T10, which provide transmission speeds up to 10 Mbps and 100
Mbps respectively.
Factory default settings are the settings that originally applied for a device when it was
first delivered from the factory. If it should become necessary to reset a device to its factory default
settings, this will, for many devices, completely reset any settings that were changed by the user.
Firewall works as a barrier between networks, e.g. between a Local Area Network and the
Internet. The firewall ensures that only authorized users are allowed to access the one network
from the other. A firewall can be software running on a computer, or it can be a standalone
hardware device.
Focal length is measured in millimeters; the focal length of a camera lens determines the
width of the horizontal field of view, which in turn is measured in degrees.
FPS (frames per second) a measure of how much information is used to store and display
motion video. The term applies equally to film video and digital video. Each frame is a still image;
displaying frames in quick succession creates the illusion of motion. The more frames per second
(fps), the smoother the motion appears.
Frame is a complete video image. In the 2:1 interlaced scanning format of the
RS-170 and CCIR formats, a frame is made up of two separate fields of 262.5 or 312.5 lines
interlaced at 60 or 50 Hz to form a complete frame, which appears at 30 or 25 Hz. In video
cameras with a progressive scan, each frame is scanned line-by-line and not interlaced; most are
also displayed at 30 and 25 Hz.
FTP (File Transfer Protocol) is an application protocol that uses the TCP/IP protocols,
used to exchange files between computers/devices on networks.
Full-duplex means transmission of data in two directions simultaneously. In an audio
system this would describe e.g. a telephone system. Half-duplex also provides bi-directional
communication, but only in one direction at a time, as in a walkie-talkie system.
G.711 is the default pulse code modulation (PCM) standard for Internet Protocol (IP) private
branch exchange (PBX) vendors, as well as for the public switched telephone network (PSTN).
G.711 digitizes analog voice signals producing output at 64 kilobits per second (Kbps).
Gain is the amplification factor and the extent to which an analog amplifier boosts the
strength of a signal. Amplification factors are usually expressed in terms of power. The decibel (dB)
is the most common way of quantifying the gain of an amplifier.
Gateway is a point in a network that acts as an entry point to another network. In a
corporate network for example, a computer server acting as a gateway often also acts as a proxy
server and a firewall server. A gateway is often associated with both a router, which knows where