user manual

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AXIS 210/210A/211/211A - Glossary of Terms
NWAY - A network protocol that automatically negotiates
the highest possible common transmission speed between
two devices.
PAL - Phase Altering Line. PAL is the standard format used
for televisions in most of the world (other than the US,
Canada, and Japan).
PCM - Pulse Code Modulation. Analog signal converted
directly to a digital.
Ping - A small utility used for sending data packets to
network resources to check that they are working and that
the network is intact.
Pre/post alarm image - The images from immediately
before and after an alarm.
Protocol - A special set of rules governing how two entities
will communicate. Protocols are found at many levels of
communication, and there are hardware protocols and
software protocols.
Router - A device that determines the next network point to
which a packet should be forwarded on its way to its final
destination. A router is often included as part of a network
switch (see below).
RTP- Real-Time Transfer Protocol. A transfer protocol
designed for delivery of live contents, e.g. MPEG-4.
Simplex - In simplex operation, a network cable or
communications channel can only send information in one
direction.
SMTP - A common e-mail protocol.
SNMP - Simple Network Management Protocol. An
application layer protocol that facilitates the exchange of
management information between network devices. It is
part of the Transmission Control Protocol/Internet Protocol
(TCP/IP) protocol suite.
Subnet Mask - An IP address consists of two components:
the network address and the host address. “Subnetting’
enables a network administrator to further divide the host
part of the address into two or more subnets. The subnet
mask identifies the subnet to which an IP address belongs.
Switch - Whilst a simple hub transmits all data to all
devices connected to it, a switch only transmits the data to
the device it is specifically intended for.
TCP/IP - Transmission Control Protocol/Internet Protocol. A
suite of network protocols that determine how data is
transmitted. TCP/IP is used on many networks, including the
Internet. TCP keeps track of the individual packets of
information and IP contains the rules for how the packets
are actually sent and received.
URL - Uniform Resource Locator. An “address" on the
network.
Varifocal - A varifocal lens provides a wide range of focal
lengths, as opposed to a lens with a fixed focal length,
which only provides one.
WAN - Wide-Area-Network. Similar to a LAN, but on a
larger geographical scale.
Web server - A program on a computer (server) providing
the resources (e.g. web pages) requested by the user (client).