2. CONTENTS
• Communication Channel
• Types of communication channel
• Guided media
• Twisted pair or wire pair cable
• Coaxial cable
• Fiber optic cable
• Unguided media
• Microwaves
• Communication satellite
• Broadcast radio
• Cellular radio
• Infrared
3. COMMUNICATION CHANNEL
A path through which information is transmitted from
one place to another is called communication channel.
TYPES:
• Guided media
• Unguided media
4. GUIDED MEDIA
The type of communication media in which communication
devices are directly linked with each other via cables or
physical media is called guided media.
EXAMPLES:
•Twisted pair or wire pair cable
• Coaxial cable
• Fiber optic cable
5. TWISTED PAIR OR WIRE PAIR CABLE
• Most common.
• Pair of copper wires.
• Twisted wires.
• Data transmission speed: 9600 bps.
• Two types:
Shielded Twisted Pair (STP)
Unshielded Twisted Pair (UTP)
6. COAXIAL CABLE
• Other name ‘coax’.
• Better than twisted pair cable.
• Single copper wire (Inner conductor).
• Three layers around copper wire:
Inner Insulating Layer
Copper Mesh
Outer Insulating Layer
• Data transmission speed: 10 Mbps.
• Expensive.
7. FIBER OPTIC CABLE
• Fast communication media.
• Thousands of thin strands (optical fiber).
• Cladding.
• Jacket.
• Refraction phenomenon.
• Light waves.
• Converters on both ends.
• Data transmission speed: 1Gbps or 2Gbps
8. UNGUIDED MEDIA
The type of communication media in which communication
devices sends and receives data signals through air or space
is called unguided media
EXAMPLES:
• Microwaves
• Communication satellite
• Broadcast radio
• Cellular radio
• Infrared
9. MICROWAVES
• Very high speed transmission.
• Through air or space.
• Fixed wireless.
• Line of sight transmission.
• Relay station or booster:
• Antenna, transmitter, receiver
• 40-50 feet above earth
• Distance of 20-30 miles
• Speed: 150 Mbps.
10. COMMUNICATION SATELLITE
• Space station
• Earth based stations
• 22330 miles above earth
• Up linking
• Down linking
• Speed: 1 Gbps
11. BROADCAST RADIO
• Wireless transmission media
• Through radio signals
• Receiver has antenna
• Bluetooth: Short range broadcast radio
• Speed 1Mbps
• Bluetooth: personal computers and mobile
devices
12. CELLULAR RADIO
• For mobile communications.
• Cell phones and wireless modems.
• Cell phone uses high frequency radio waves.
