transmission media department of ce/it. introduction data is transmitted form one place to another...
TRANSCRIPT
Introduction
Data is transmitted form one place to another using some
transmission media.
The transmission medium is the physical path between
transmitter and receiver for the data communications
signal energy.
It is known by several alternative names such as
transmission path, line, channel, trunk, link, circuit, et.
The medium can be wire, air or vacuum, or optical fiber.Department of CE/IT
Characteristics of Transmission media
DistanceBandwidthAttenuationResistance SecurityCastlinkage
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Types
Transmission media can be broadly categorized into two
types
Guided Transmission Media
Unguided Transmission Media
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Guided media
Guided transmission media uses a ”cabling” system that guides
the data signals along a specific path.
The data signals are bound by the “cabling” system.
Guided Media is also known as Bound Media.
The three guided transmission media are as follows:
Twisted Pair Cable
Coaxial Cable
Optical fiber
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Twisted Pair Cable
Twisted-pair cable is a type of cabling that is used for
telephone communications and most modern Ethernet
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.
Two basic types of twisted-pair cable exist:
unshielded twisted pair (UTP)
Shielded twisted pair (STP).
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Common use
Voice Telephony (including private branch exchanges)
Digital Subscriber Line (DSL) in many flavors
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Co-axial Cable
Coaxial Cable consists of 2 conductors.
The inner conductor is held inside an insulator with the other
conductor woven around it providing a shield.
An insulating protective coating called a jacket covers the
outer conductor. The outer shield protects the inner conductor
from outside electrical signals.
The distance between the outer conductor (shield) and inner
conductor plus the type of material used for insulating the
inner conductor determine the cable properties or impedance. Department of CE/IT
Common Uses:
Cable TV (Old: RG-59; New: RG-6)
Ethernet (RG-58: 10Base2; RG-8: 10Base5)
Amateur radio
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Fiber optic Cable
Description:
A thin glass core surrounded by cladding that reflects
light into the core, surrounded by a protective
plastic buffer/jacket.
Example:
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Introduction
Unguided media relates to data transmission through the
air and is commonly referred to as wireless. The
transmission and reception of data is carried out using
antenna.
These media can carry such electromagnetic signals as
microwave, infrared light waves, and radio waves.
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Laser
Unidirectional
High bandwidth
Cannot penetrate thick fog or rain
(Doesn't require an FCC license)
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Infrared
Mostly directional
Cheap
Do not pass through solid objects (so no license is required)
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