Data communication basics

What is data communication

Data communication is process of exchanging the digital data between devices over a network. It involves a transmission medium (Wired / Wireless)

• Connecting to your home WiFi
• Accessing youtube video from your phone
• Sending and receiving messages from your friends

Elements of data communication

• Sender (Source) : The device who generate and transmit the data. (ex. a laptop)
• Receiver (Destination) : The device that receive the data sent by the sender. It receives and process the data. (ex. server)
• Message : The actual data that is being transmitted. (ex. images)
• Transmission medium : A physical or wireless medium through which the data travells. (ex. WiFi)
• Protocols : A predefiend set of rule, which get followed for transmission. (ex. HTTP)

Process of a data communication

1. Generation : Sender generates a data. (messages, images ...)
2. Encoding : Data get converted into digital form. (bits)
3. Transmission : Data sent through a transmission medium. (Wired / Wireless)
4. Receptions : Transmitted data get received at receiver end.
5. Decoding : Received data get converted back to its previous original form.
6. Processing : Data get processed or stored accordingly

Types of Data Transmission

Transmission Modes

1. Simplex : Data is only sent from sender to receiver. Data flows in only a single direction (Sender ⟶ Receiver). (ex. Radios, TV boradcasts)
   
2. Half-duplex : Data can be transmitted in both direction, but only in one diraction at a time. (Sender ⟶ Receiver, Sender ⟵ Receiver). (walkie-talkies)
   
3. Full-duplex : Data can be transmitted in both direction simultaneously. (Sender ⇌ Receiver). (ex. Phone calls)
   

Data Transmission Techniques

1. Serial transmission : Serial transmission is a method of sending data one bit at a time over a single communication line. (ex. USB)
   
2. Parallel transmission : In parallel transmission, multiple bits of data are sent through multiple communication lines.(Printers)