Cables are commonly used to carry
communication signals within LAN. There are three common types of cable media
that can be used to connect devices to a network and they are coaxial cable,
twisted-pair cable, and fiber-optic cable.
Coaxial Cable
Coaxial cable looks similar to the cable
used to carry TV signal. A solid-core copper wire runs down the middle of the
cable. Around that solid-core copper wire is a layer of insulation, and
covering that insulation is braided wire and metal foil, which shields against
electromagnetic interference. A final layer of insulation covers the braided
wire.
There are two types of coaxial cabling:
thinnet and thicknet. Thinnet is a flexible coaxial cable about ¼ inches thick.
Thinnet is used for short-distance. Thinnet connects directly to a
workstation’s network adapter card using a British Naval Connector (BNC). The
maximum length of thinnet is 185 meters. Thicknet coaxial is thicker cable than
thinnet. Thicknet cable is about ½ inch thick and can support data transfer
over longer distances than thinnet. Thicknet has a maximum cable length of 500
meters and usually is used as a backbone to connect several smaller
thinnet-based networks.
The bandwidth for coaxial cable is 10 mbps
(megabits per second).
Twisted Pair Cable
Twisted-pair cable is the most common type
of cabling you can see in today’s LAN networks. A pair of wires forms a circuit
that can transmit data. The pairs are twisted to provide protection against
crosstalk, the noise generated by adjacent pairs. When a wire is carrying a
current, the current creates a magnetic field around the wire. This field can
interfere with signals on nearby wires. To eliminate this, pairs of wires carry
signals in opposite directions, so that the two magnetic fields also occur in
opposite directions and cancel each other out. This process is known as
cancellation. Two Types of Twisted Pairs are Shielded Twisted Pair (STP) and
Unshielded Twisted Pair (UTP).
Unshielded twisted-pair (UTP) cable is the
most common networking media. Unshielded twisted-pair (UTP) consists of four
pairs of thin, copper wires covered in color-coded plastic insulation that are
twisted together. The wire pairs are then covered with a plastic outer jacket.
The connector used on a UTP cable is called a Registered Jack 45 (RJ-45)
connector. UTP cables are of small diameter and it doesn’t need
grounding. Since there is no shielding for UTP cabling, it relies only on
the cancellation to avoid noise.
UTP cabling has different categories. Each
category of UTP cabling was designed for a specific type of communication or
transfer rate. The most popular categories in use today is 5, 5e and 6, which
can reach transfer rates of over 1000 Mbps (1 Gbps).
The following table shows different UTP
categories and corresponding transfer rate.
|
UTP Category
|
Purpose
|
Transfer Rate
|
|
Category 1
|
Voice Only
|
|
|
Category 2
|
Data
|
4 Mbps
|
|
Category 3
|
Data
|
10 Mbps
|
|
Category 4
|
Data
|
16 Mbps
|
|
Category 5
|
Data
|
100 Mbps
|
|
Category 5e
|
Data
|
1 Gbps
|
|
Category 6
|
Data
|
1/10 Gbps
|
Optical Fiber Cabling
Optical Fiber cables use optical fibers
that carry digital data signals in the form of modulated pulses of light. An
optical fiber consists of an extremely thin cylinder of glass, called the core,
surrounded by a concentric layer of glass, known as the cladding. There are two
fibers per cable—one to transmit and one to receive. The core also can be an
optical-quality clear plastic, and the cladding can be made up of gel that
reflects signals back into the fiber to reduce signal loss.
There are two types of fiber optic cable:
Single Mode Fibre (SMF) and Multi-Mode Fibre (MMF).
1. Single Mode Fibre (SMF) uses a single
ray of light to carry transmission over long distances.
2. Multi Mode Fibre (MMF) uses multiple
rays of light simultaneously with each ray of light running at a different
reflection angle to carry the transmission over short distances
More
Related Network Cable Tips:
Great info in the blog post.
ReplyDeleteThe types of network cable described in the post in a very descriptive manner.
Thanks for sharing.
Managed IT San Diego