4. These signal are continuous waves with no discontinuity
or break in between.
For Example: Sound, pressure, temperature etc.
An important feature of analog signals is that they can
travel long distances but they can distorted by noise.
Signal strength is increased with the help of booster.
Analog Signals
5. Digital signals are discrete on-off pulses. i.e. they represent
information in terms of only two states of signals, either one
or zero.
Digital signals are less affected by disturbances or noise and
they can be repeatedly strengthened for long distance
transmission without accumulating noise.
Amplifier first absorb and then regenerate them at regular
intervals.
Digital Signal
6. Communication channels, known as lines, are used in
data communication to transport data from one
location to another.
Communication Channels
8. Guided transmission media means the data signals
are guided along the path like cabling system.
They don't have any other way to go, they have
to pass through the given cable or wire.
Guided
10. A twisted pair consists of two insulated copper wires arranged in
a regular spiral pattern.
Twisted pair may be used to transmit both analog and digital
transmission.
Twisted pair is limited in distance, bandwidth, and data rate.
Twisted Pair
12. Con..
Shielded Twisted Pair (STP)
Metal protected that reduces interference
More expensive
Easiest to install
Harder to handle (thick, heavy)
13. Coaxial Cable
Coaxial cable is a copper or aluminum wire wrapped
with spacers to insulate
The copper conductor
Insulation layer of plastic foam
Second conductor or shield of wire mesh tube or metallic foil
Outer jacket of tough plastic
14. Con…
Coaxial cable can be used over longer distances and
support more stations on a shared line than twisted
pair.
Coaxial cable is used in a wide variety of applications.
15. Fiber Optics
Fiber optic cable consist of thousands of very thin filaments of glass.
Through this cable data transmission is done through « Light ray
signal transmission» rather than electrical signal transmission.
It has inner core of glass that conducts light. This inner core is
surrounded by cladding.
16. Each fiber is then surrounded by plastic sheath
17. Unguided Media
It refers to those channels that transmit data and
information in the form of Waves.
Data is transmitted through the air instead of cable
There is no physical path between two devices for
transmission of data.
18. Con..
Data signals are not bounded to cabling media
therefore it is also know as unbounded media.
Unguided Media
Microwave Satellite Mobile
19. Microwave
These are the communication channels in which data
is transmitted through air instead of cables.
20. Con..
Microwave is the high frequency waves that can only be
traveled in straight lines.
These waves cannot bend or pass through obstacles.
It is limited to particular city community.
The transmitter and receiver are mounted on a very high
tower should be in a line of sight.
21. Con..
This may be not possible for long distance
transmission.
Repeater on antennas are mounted at very high
towers usually 20 to 30 miles apart to overcome the
problem of weakening signals and line of sight.
22. Satellite serve as relay stations for communication
signals transmitted from earth station.
Satellites are lunched by rockets to an orbit around
the earth at a distance of approximately 35000 km.
Satellite Communication
23. Satellite Communication
Main problem with microwave communication is that the
curvature of earth and mountains and other structure often
blocks the line of sight.
Instead of antenna, satellite can also be used to transmit
data.
24. Con…
Earth station can both receive and send the message.
The transmission from earth station to satellite is
called uplink and transmission from satellite to earth
is called downlink.
25. Advantages of Satellite
Communication
A large volume of data can be transmitted at a very high speed.
Transmission and reception costs are independent of the
distance between two points.
Different communication satellites are used to carry different
kinds of information.
Telephone calls, TV Channels, Internet, military communication,
weather and radio station use these satellite for broadcasting.
26. Disadvantages Satellite
The bad weather can severely affect the quality of
transmission
Satellite transmission causes security problems because
it is easy to intercept the travels though the air.
Its cost of transmission is very high.
Satellite delay is still present in all our satellite
communication.
27. Radio
No microwave or satellite links, especially for short
ranges, are required for this channel of data
communication.
It is used to connect computer and peripheral
equipment or computers and local area network.
28. Network Topology is the schematic description of a
network arrangement, connecting various
nodes(sender and receiver) through lines of
connection.
Network Topology
29. Bus Topology
Ring Topology
Star Topology
Mesh Topology
Types of Topology
30. Bus topology is a network type in which every
computer and network device is connected to single
cable. When it has exactly two endpoints, then it is
called Linear Bus topology.
Bus Topology
31. It is called ring topology because it forms a ring as
each computer is connected to another computer,
with the last one connected to the first. Exactly two
neighbors for each device.
Ring Topology
32. In this type of topology all the computers are
connected to a single hub through a cable. This hub is
the central node and all others nodes are connected
to the central node.
Star Topology
33. It is a point-to-point connection to other nodes or
devices. All the network nodes are connected to each
other.
Mesh Topology
34. Local Area Networks(LAN)
Campus area network (CAN)
Metropolitan area network (MAN)
Wide area network (WAN)
Types of Networks
35. A local area network (LAN) is designed to connect
personal computers and other digital devices
within a half-mile or 500-meter radius.
LANs also are used to link to long-distance wide area
networks and other networks around the world using
the Internet.
Local Area Networks(LAN)
36. Ethernet is the most widely used local area network
protocol.
It is used in contrast with WAN (wide area network) which
spans for much larger geographical areas. Ethernet is a
network protocol that controls how data is transmitted
over a LAN.
Ethernet supported a data transfer rate of 10 megabits per
second (Mbps).
Ethernet
37. Fast Ethernet is backward-compatible with Standard
Ethernet, but it can transmit data 10 times faster at a
rate of 100 Mbps.
Fast Ethernet
38. Gigabit Ethernet is part of the Ethernet family of
computer networking and communication standards.
The Gigabit Ethernet standard supports a theoretical
maximum data rate of 1 gigabit per second (Gbps).
Gigabit Ethernet
39. A peer-to-peer network treats all processors equally
and is used primarily in small networks with 10 or
fewer users.
The various computers on the network can exchange
data by direct access and can share peripheral devices
without going through a separate server.
Peer-to-peer
40. A metropolitan area network (MAN) is a network that
spans a metropolitan area, usually a city and its major
suburbs. Its geographic scope falls between a WAN
and a LAN.
Metropolitan area network (MAN)
41. Wide area networks (WANs) span broad geographical
distances, entire regions, states, continents, or the
entire globe.
The most universal and powerful WAN is the Internet.
Computers connect to a WAN through public
networks, such as the telephone system or private
cable systems, or through leased lines or satellites.
Wide area networks (WANs
