Communication Channels
Transcript of Communication Channels
What is Communication Channel ?
• Transfers data or
information from one place
to another
• Also known as Transmission
Media
Channel
Sender
Receiver
Twisted Pair Cable
• Consisting of pairs of
twisted copper wires.
• Can transmit 1 Mbps over
short distances (less than
100m).
• Mainly used to transmit
analog signals.
APPLICATIONS
• They are used in telephone lines to provide voice and data channels.
• Local area networks
COAXIAL PAIR CABLE
Coaxial consists of :
A core made of solid copper,
Surrounded by insulation,
A braided metal shielding,
And an outer cover.
CHARACTERS
Bandwidth:
80 times greater than that of twisted pair cables
Speed:
Data transmission speed is 10Mbps.
BENEFITS Most versatile medium
Television distribution
Long distance telephone transmission
Can carry 10,000 voice calls simultaneously
Short distance computer systems links
Local area networks
Fiber-Optic Cable
• Uses reflection to guide
light through a channel
• Core is of glass or plastic
surrounded by Cladding
• Cladding is of less dense
glass or plastic
APPLICATIONS & BENEFITS
Greater capacity:
Data rates of hundreds of Gbps
Smaller size & weight
Lower attenuation
Frequency Range
Typical Attenuation
Typical Delay Repeater Spacing
Twisted pair (with loading)
0 to 3.5 kHz 0.2 dB/km @ 1 kHz
50 µs/km 2 km
Twisted pairs (multi-pair cables)
0 to 1 MHz 0.7 dB/km @ 1 kHz
5 µs/km 2 km
Coaxial cable 0 to 500 MHz 7 dB/km @ 10 MHz
4 µs/km 1 to 9 km
Optical fiber 186 to 370 THz
0.2 to 0.5 dB/km
5 µs/km 40 km
COMPARISON
CHARACTERS
• Waves are transmitted via microwave relay stations.
• Micro waves are unidirectional.
• Microwave propagation is line of sight.
• Very high frequency Micro waves can not penetrate walls.
• Data transmission speed is 150 Mbps.
BENEFITS
• Typical uses
Television
Long distance telephone
Private business networks
Global positioning
CHARACTERS
• Signals are transmitted from
Earth stations to Satellites
• Data transmission speed is
upto 1Gbps.
BENEFITS:• Transmits large amount of Data.
• Data transmission speed is Very High.
DISADVANTAGES:• Effected by bad weather.
• Have security problems.
• It is costly.
BROADCAST RADIO
• Used to send signals over long & short distances.
• Transmitter sends messages
• Receiver receives messages
• Transceiver can do both
Example:
• Bluetooth
Infrared
• Line of sight transmission
• Short Range
Example:
• Data transmission among
a computer and wireless
keyboard or mouse