Techniques of Data Transmission.

Techniques of Data Transmission:

           

The telephone lines transmit the human voice and data in a computer system, and this data remains in computer in the form of pulses. Hence for communication between computer and telephone line, it’s necessary that the digital pulse is converted into analog signal, before they are transmitted.

            The analog signal needs to be converted into digital pulse, so that the data can be received by the computer, after its journey is over in telephone lines. The process of converting digital pulses to an analog signal is called Modulation. The process of reconverting an analog signal to digital pulses is called Demodulation.

            The device that accomplishes modulation-demodulation process is called MoDem.

Transmission Modes:

            Data transmission any one of the following mode:

a)                  Simplex mode

b)                  Half-duplex mode

c)                  Full-duplex mode

Simplex Mode:

            In simplex mode data can be transmitted in one direction. The device using simplex mode of data transmission. A device using the simplex mode of transmission can either send or receive data, but it cannot do both.

Half-duplex Mode:

            In half duplex mode, data can be transmitted back and forth between two stations but data can only go in one of the direction at any point of time. An example i.e. wireless (generally used by military) where the user must either or listen, but can not do both at the same time.

Full-duplex Mode:

            The full duplex mode allows a devices to receive and send data simultaneously. A full duplex mode is faster, since it avoids the delay that occurs in half duplex circuit.