Transmission media can be either guided or unguided. Guided media uses physical pathways like cables to transmit signals while unguided or wireless media transmits electromagnetic waves without a physical conductor. Wireless transmission uses radio waves, microwaves, and infrared signals to transmit data through methods like ground propagation, sky propagation, and line-of-sight propagation from an antenna of one device to another.

1. Transmission Media:

2. Transmission Media: (conti…..)
 Computers and other
telecommunication devices use
signals to represent data. These
signals are transmitted from one
device to another in form of
electromagnetic energy, which is
propagated through transmission
media.

3. Transmission Media: (conti….)
 For the purpose of
telecommunications, transmission
media ca be divided into two
categories: Guided and Unguided.
 Guided Media, which are those that
provide a conduit from one device to
another, include twisted-pair cable,
coaxial cable, and fiber-optic cable.

5. Unguided Media: Wireless
 Unguided media transport electromagnetic
waves without using a physical conductor.
 This type of communication is often
referred to as a Wireless Communication.
 Signals are normally broadcast through air
and thus are available to anyone who has a
device capable to receiving them.
 Unguided signals can travel from source to
destination in several ways.

6.  Unguided signals can travel from
source to destination in several ways.
there is ground propagation, sky
propagation, and line-of-sight
propagation.
 In ground propagation,radio waves
travel through through the lowest
portion of the atmosphere,hugging
the data.

7.  In sky propagation, higher-frequency
radio waves radiate upward into the
ionosphere where they are reflected
back to the earth.
 In line-of-sight propagation, very
high-frequency signals are
transmitted in straight lines directly
from antenna to antenna.

8.  Wireless transmission divided into
three groups.
 1:Radio waves
 2:Micro waves
 3:Infrared

9. Radio waves:
 Radio waves are used for multicast
communications, such as radio and
television.

10. Microwaves:
 Microwaves are used for unicast
communication such as cellular
telephones, satellite networks, and
wireless LANs.

11. Infrared:
 Infrared signals can be used for
short- range communication is a
closed area using line-of-sight
propagation.