The document discusses physical transmission networking, which involves the transfer of data between computers and devices through various media. It categorizes transmission media into wired (guided) and wireless (unguided), detailing types such as twisted pair, coaxial cable, and fiber optic. Additionally, it highlights the significance of bandwidth, advantages and disadvantages of each medium, and specifies that fiber optic cables offer the highest speed transmission.

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Physical Transmission
NETWORKING

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 The transmission of data from
one computer to another, or from one device
to another.
 A communications device, therefore, is any
machine that assists data transmission. For
example, modems, cables, and ports are
all communications devices
Computer Communication

3.  Anything that can carry information from a
source to a destination or from one point to
other point.
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Transmission Media/Channel/Link

4. Physical
Transmission
Transmission Media
Wire (guided)
Coaxial cable
Twisted Pair
UTP
STP
Fiber Optic
Wireless (unguided)
Radio waves
Microwave
Infrared
Satellite
Laser
Signaling Techniques
Baseband
Transmission
Broadband
Transmission
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Physical Transmission

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 There are two categories of Transmission
media:
1. Wired (Guided) media
 In wired media, communication devices are directly
connected with each other by
using some physical media like wires. Wireless
(Unguided) media
 Unguided media transport signals without using a
physical media.
Transmission Media

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• For Guided Medium
—The medium is more important
• For Unguided
—The bandwidth produced by the antenna is more important
Overview

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 Bandwidth:
 The amount of data that can be transferred
through a communication medium in a given
time is called bandwidth.
 The bandwidth of digital signal is measured in
bits per second 0" Bytes per second.
Design Factors for Transmission Media

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1. Wired (Guided) media

9. There are three categories of guided media:
1. Twisted Pair :
1. Unshielded twisted pair (UTP)
2. Shielded twisted pair (STP)
2. Coaxial Cable
3. Fiber Optic Cable
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I. Wired (Guided) media:

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 Twisted pair is the most commonly used physical
transmission medium.
 It is used in local area network to connect computers
and other devices.
 Twisted pair cable consists of copper wires.
 The pair of wires is covered by a Plastic insulation
and it is twisted together.
 Twisting of Wires Protects them from interference by
external electromagnetic waves.
 Low frequency transmission medium
Twisted Pair Wires

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 STP (shielded twisted pair)
◦ the pair is wrapped with metallic foil or braid to
prevent the pair from electromagnetic interference
 UTP (unshielded twisted pair)
◦ each wire is insulated with plastic wrap, but the pair is
encased in an outer covering
Types of Twisted Pair

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Twisted Pair Cable

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Twisted Pair Advantages & Disadvantages
Advantages Disadvantages
 Inexpensive and
available
 Flexible and light weight
 Easy to work with and
install
 Sensitivity to
interference and noise
 Relatively low
bandwidth (3000Hz)

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 Carries signals of higher frequency ranges than
twisted pair cable.
 Has an inner conductor
 Inner conductor is enclosed in an insulator,
 which is again enclosed in an outer conductor of
metal braided mesh.
 Used for cable television, LANs, telephony
Coaxial Cable (or Coax)

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16.  Optical fiber is made of glass or plastic and transmits signals in the form of
light.
 The cable consists of a strand of glass (core) surrounded by a glass tube
(cladding).
 Its surrounded by a plastic isolation layer for protection .
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Fiber Optic Cable

17.  Relatively new transmission medium used by telephone
companies in place of long-distance trunk lines
 Fiber Optic works on the properties of light
 From one end of it light is emitted, it travels through it
and at the other end light detector detects light stream and
converts it to electric data form.
 Fiber Optic provides the highest mode of speed.
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Fiber Optic Cable

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