Common Peripheral Ports
Common peripheral ports include the
serial and parallel ports. Serial ports are often used for a
workstation's mouse or keyboard, and referred to as a slow port
because data can flow only in one direction.
Parallel ports are used for devices
which are quicker and connect outside of the workstation. Data can be
transmitted in both directions, making the connection faster. A
printer for example connects to a parallel cable and port to speed up
printing processes.
Data Bus connectors (DB Connectors) are
a "D" shaped connector used to connect serial and parallel cables to the computer.
DB connectors are usually referred
to with as DB-x, x representing the number of wires, DB-9, DB-15, and
DB-25 are most commonly used.
External SCSI Connections
Small Computer Standard Interface
(SCSI) enables workstations to be able to connect to and communicate
with peripheral hardware, such as CD-ROMs, disk drives, or scanners.
SCSI provides faster data transmission than the parallel port, is used
for high-performance systems, and has the capability to chain together
up to 7 or 15 devices.
Print Server
There are two types of print servers, dedicated and non-dedicated. Both types receive requests from end-users and direct the requests to a printer pool. A print server is secure because it has no client access into the network. The difference between dedicated and non-dedicated print servers is dedicated is only used as a print server, while non-dedicated will also have some other network server functions.
Hubs
Using either twisted-pair or coaxial
cabling, hubs connect a number of computers and devices together.
Depending on the cabling, hubs can be used to strengthen signals if
cables are not long enough and signals begin to fade. Hubs are
normally used for star topologies, where each cable segment is
connected to the hub. 
Routers
Routers, which operate on the third
layer of the OSI Model, route data packets to a destination based on
the routing address provided by the data packets. Routers are
responsible for addressing and translating logical addresses into the
physical address of a packet.

Routers are either static or dynamic
devices and are normally connected in a mesh topology with other
routers. Statically configured routers can not communicate with other
routers, they have a determined fixed route, which is manually entered
by the administrator. Dynamically configured routers have the ability
to communicate with other routers to determine the best path to route
a packet by a variety of protocols, including RIP, IGRP, EIGRP, and
OSPF.
Brouters
A brouter is a device, which functions
as a bridge and a router. If a brouter receives a packet, it must
determine the IP address. If the IP address is not connected to any of
its ports, it must route the packet to another location. However, if
it receives a packet with an IP address connected to one of its ports,
the brouter acts as a bridge and delivers the packet to its
destination.
Bridges
Bridges are devices, which connect two
different networks, or network segments, together and filter traffic
from each network. The bridge builds a table of physical (hardware)
addresses, learning the hosts, which exists on each of its ports. The
bridge examines the destination MAC address of each frame; if the
destination address is local (on the same bridge port, based on the
bridging table), the frame is not sent. However, if the destination
MAC address is of a different bridge port from the source address, the
frame is forwarded to the non-local destinations. Bridges provide
connectivity with Layer 2 filtering. Some bridges will connect
networks of differing LAN technologies (like Ethernet to Token Ring).
Since the bridge operates at layer 2, it forwards all upper level
protocols.
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Patch Panels
Patch panels, which are an integral
part of structured cabling installations, consist of a row of female
connectors (or ports) where every cable from different work areas
connects directly to the back of the patch panel. They provide support
for a UTP, STP, fiber ports, and various CAT ratings of UTP cabling. 
UPS
Uninterruptible Power Supply (UPS)
provides protection from spikes and sags that may come over the
electrical wires. While the server is plugged in, the battery charger constantly charges the battery. In case of a power outage, the fully
charged battery will provide operations to continue or provide enough time for the
server to shut down properly. 
NIC
Network Interface Cards (NICs) allow
the communication between a computer and the network, providing a
physical connection. In order for the computer to interact with the
NIC, the computer must have the proper drivers installed. Each NIC is
assigned a unique address called the MAC address. This address is also
the physical address and is burned onto the NIC by its manufacturer.
No two MAC addresses are or can be alike. 
Token Ring Media Filters
A token ring media filter is a passive
device, which is used to convert output signals from a token ring NIC,
so that it may be compatible with different media types, such as STP
cable or different terminations, such as a DB-9 connector. Media
filters are also designed to eliminate unwanted high frequency
emissions and adjust inputs when using UTP cable.
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