MCSE : Security Specialist
Network interface cards/ISDN adapters/system area network cards
Network Interface Card, or NIC is a hardware card installed in a
computer so it can communicate on a network. The network adapter
provides one or more ports for the network cable to connect to, and
it transmits and receives data onto the network cable.
Every
networked computer must also have a network adapter driver, which
controls the network adapter. Each network adapter driver is
configured to run with a certain type of network adapter.
A
networked computer must also have one or more protocol drivers
(sometimes called a transport protocol or just a protocol). The
protocol driver works between the upper-level network software and
the network adapter to package data to be sent on the network.
In
most cases, for two computers to communicate on a network, they must
use identical protocols. Sometimes, a computer is configured to use
multiple protocols. In this case, two computers need only one
protocol in common to communicate. For example, a computer running
File and Printer Sharing for Microsoft Networks that uses both
NetBEUI and TCP/IP can communicate with computers using only NetBEUI
or TCP/IP.
ISDN
Integrated Services Digital Network adapters can be used to send
voice, data, audio, or video over standard telephone cabling. ISDN
adapters must be connected directly to a digital telephone network.
ISDN adapters are not actually modems, since they neither modulate
nor demodulate the digital ISDN signal.
Like
standard modems, ISDN adapters are available both as internal
devices that connect directly to a computer's expansion bus and as
external devices that connect to one of a computer's serial or
parallel ports. ISDN can provide data throughput rates from 56 Kbps
to 1.544 Mbps (using a T1 carrier service).
ISDN
hardware requires a NT (network termination) device, which converts
network data signals into the signaling protocols used by ISDN. Some
times, the NT interface is included, or integrated, with ISDN
adapters and ISDN-compatible routers. In other cases, an NT device
separate from the adapter or router must be implemented.
ISDN
works at the physical, data link, network, and transport layers of
the OSI Model.
Wireless access points
A wireless network adapter card with a transceiver sometimes called
an access point, broadcasts and receives signals to and from the
surrounding computers and passes back and forth between the wireless
computers and the cabled network.
Access points act as wireless hubs to link multiple wireless NICs
into a single subnet. Access points also have at least one fixed
Ethernet port to allow the wireless network to be bridged to a
traditional wired Ethernet network..
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