Data communication

What is data communication? Transmission of data from one place to another place is called data communication.

Basic parts of data communication Three components are essential in data communication. 1.Sender / Source 2. Data Communication Medium 3. Receiver / Sink

Basic parts of data communication Sender/Source Receiver/Sink Medium

Sender / Source Sender or source is the data producer. The receiver is the person who gets data at the end. E.g.: Imagine you call a friend of yours. Then you become the Sender or Source. SenderReceiver

Data Communication Medium The medium which is used to transmit data to the receiver. E.g.: In the example mentioned above, telephone becomes the data communication medium there. Receiver

Data Communication Media/Medium Various media are used for data communication. It is possible to divide all these media into two main types. 1) Guided Media 2)Radiated /Unguided Media

Guided Media A particular physical medium is used for data communication.

Radiated Media Communicating data using media which is not physical, is called radiated media. Eg: Radio transmission, Infrared, Microwaves

Guided Media Following wires can be classified under guided media. Twisted wire pair (Twisted pair cables) Co-axial Cable / Coaxial cables Fiber optic cables

Twisted wire pair

Advantages of Twisted pair cable Can carry both analog and digital data. Easy to implement and terminate. It is the least expensive media of transmission for short distances.

Disadvantages of Twisted pair cable Very poor security and is relatively easy to tap. Thin in size, they are likely to break easily.

Applications of Twisted Pair Cables Telephone lines to carry voice and data channels. ADSL lines. Some Local area networks. ISDN (Integrated Services Digital Network).

Co-axial Cable / Coaxial cable It has a copper net woven around a copper wire.

Applications of Coaxial cables Used in digital transmission Used for analogue transmission Used for TV antennas and Cable TV

Advantages of Coaxial cables Easy to install Not expensive Since it shielded, can span a higher distance at higher speed than twisted pair. Less data loss

Disadvantages of Coaxial cables Higher cost compared to twisted pair Cables easily get damaged

Fiber Optics

Applications of Fiber Optics Military -They offer better performance and greater security for their signals. They're strong, and lightweight, and can also be used outdoors in harsh environments. Radar systems Telecommunications companies to transmit telephone signals Internet communication Cable television signals

Advantages of Fiber Optics Carry signals with much less energy loss than copper cables. Much lighter and thinner than copper cables. Difficult to tap information. Supports for long distances. Supports for very high speed network communications.

Disadvantages of Fiber Optics It's very expensive.

Radiated Media (Unguided Media) No physical medium is used here to send data.

Radiated Media (Unguided Media) 1. Radio transmission Radio transmission, which is very familiar to our normal lives, can be used for data communication very easily.

Radiated Media (Unguided Media) 2. Infrared It has a very low frequency. These are largely used for data communication when wire- less keyboards, mouse and printers are used.

Radiated Media (Unguided Media) 3. Microwaves Used to communicate data to a long distance and short signals with contain higher frequency. Microwave links use very high frequency radio waves to transmit data through space.

Microwaves

Communication satellites

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