Data Communication

Data communication is a process of transferring data electronically from one place to another.Data can be transferred by using different medium.The basic elements of data communication are as follows: 
  • Sender: The sender is the device that sends the information. It is also called source. Normally, computer is used as sender in data communication systems.
  •  Medium :The medium is the physical path that connects the sender and the receiver.It is used to transmit the data. The medium can be a copper wire,a fiber-optic cable, airwaves etc. It is also called communication channel.
  • Receiver: The receiver is the device that accepts the information. It is also called sink . The receiver can be computer, printer or another computer related device.
Types of Data Transmission



The two forms of data transmission are as follows:

1. Digital Data Transmission:
The transfer of data in the form of digital signal is called digital data transmission. Digital signal is a sequence of voltage represented in binary form. The digital signals are in the form of electrical pulses of ON an OFF.
Digital signals are faster and efficient.They provide low error rates . They also provide high transmission speed and high- quality voice transmission. All data communication between the computers is in digital form.Computers understand and work only in digital form. The following figure represents a high voltage as a 1 and a low voltage as a 0.

2. Analog Data Transmission
Analog data transmission is the transmission of data in a continuous wave form.For example sound waves are analog signals. When we talk, we emit sound waves that consist of waveforms of high and low pressure.Analog signal is measured in volts and its frequency is in Hertz (Hz). Telephone line is most commonly used media for analog transmission of data. light, sound, radio and microwave can also be used as analog transmission media.