Description of Communication media

1. Physical Communication Media
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2. Physical Communication Media
 Wire, cable, and other tangible (touchable) materials
used to send communications signals, They are called
physical communication media.
 The physical layer is concerned with network media
and signaling. This layer produces the representation
and groupings of bits as voltages, radio frequencies,
or light pulses. Various standards organizations have
contributed to the definition of the
physical,electrical,and mechanical properties of the
media available for different data communications.

3. Transmission medium and physical layer
7.3

4. Classes of transmission media

5. GUIDED MEDIA
 Guided media, which are those that provide a conduit from
one device to another, include twisted-pair cable, coaxial
cable, and fiber-optic cable.
 Topics discussed in this section:
 Twisted-Pair Cable
Coaxial Cable
Fiber-Optic Cable

6. Twisted-pair cable
A twisted pair consists of two conductors (normally copper),
each with its own plastic
insulation, twisted together.

7. UTP and STP cables

8. RJ45 connector
RJ-45
BNC

9. UTP connector

10. Coaxial cable
Coaxial cable (or coax) carries signals of higher frequency
ranges than those in twisted-
pair cable, in part because the two media are constructed quite
differently. Instead of having two wires, coax has a central core
conductor of solid or stranded wire (usually
copper) enclosed in an insulating sheath,

11. BNC connectors

12. Optical fiber
A fiber-optic cable is made of glass or
plastic and transmits signals in the form
of light.

13. Fiber-optic cable connectors

14. UNGUIDED MEDIA: WIRELESS
Unguided media transport electromagnetic waves without
using a physical conductor. This type of communication is
often referred to as wireless communication.
Topics discussed in this section:
Radio Waves
Microwaves
Infrared

15. Electromagnetic spectrum for
wireless communication
Radio, satellite microwave,, Bluetooth, and infrared light are
all different forms of electromagnetic waves that are used to
transmit data

16. 1.Ground Propagation:
Radio waves travel through the lowest portion of the atmosphere, hugging the earth.
2.Sky Propagation:
Higher frequency radio radiate upward into the ionosphere where they are reflected back to the
earth.
3.line-of-sight Propagation: Very high frequency signals are transmitted in straight lines
directly from antenna to antenna.

17. Radio Waves
electromagnetic waves ranging in frequencies between 3 kHz and 1 GHz are normally called radio
waves;
 Between 3 KHz – 1 GHz.
 Radio waves use omnidirectional antenna.
 Radio waves used for multicast communication, such as radio and television.
 Sky Propagation. This makes radio waves a good candidate for long-distance broadcasting such
as AM radio.

18. Microwave
waves ranging in frequencies between 1 and 300 GHz are called microwaves.
However, the behavior of the waves, rather than the frequencies, is a better
criterion for classification.
Unidirectional antennas
Microwaves are used for unicast communication such as cellular telephones,
satellite networks, and wireless LANs.

19. Infrared waves
 Between 300 GHz-400 THz
 Used for short-range communication.
 Very common with remote control devices, but can also be used for
device-to-device transfers, such as PDA to computer.
 Line-of-sight propagation.
with frequencies from 300 GHz to 400 THz (wavelengths from 1 mm to 770 nm),
can be used for short-range communication. Infrared waves, having high
frequencies, cannot penetrate walls. This advantageous characteristic prevents
interference between one system and another; a short-range communication
system in one room cannot be affected by another system in the next room.
When we use our infrared remote control, we do not interfere with the use of
the remote by our neighbors.
Infrared signals can be used for short-range communication in a closed area
using line-of-sight propagation.

20.  (a) In the VLF, LF, and MF bands, radio waves follow the
curvature of the earth.
 (b) In the HF band, they bounce off the ionosphere.

21. THANK YOU
By:- A $oni
Amity university jaipur
9680520920