• सुखार्थी त्यजते विद्यं विध्यार्थी त्यजते सुखम्सु sखर्थीन: कुतॊ विद्या कुतॊ विध्यार्थीन: सुखम् ||
  • “Luxury people leave knowledge, but a student leaves Luxury No knowledge for one who seeks Luxury, No luxury for student”
  • न चोर हार्यं न च राज हार्यं न भात्रू भाज्यं न च भारकारि |व्ययं कृते वर्धत एव नित्यं विद्याधनं सर्वधनप्रधानम ||
  • Cannot be snatched away by thief, cannot be snatched away by king, Cannot be divided among brothers, Not heavy either If spent daily, it always keeps growing. The wealth of knowledge is the precious of wealth of all”

Parallel and Serial data transmission

Data Transmission

Movement of data in form of bits between two devices is data transmission. 

Parallel Transmission

Bits are organized into groups of n bits each; we send data n bits at a time instead of single bit the processes of sending and receiving data in group of bits is called parallel transmission.


The mechanism for parallel transmission use n wires to send n bits at one time.


All n bits are transmitted with each clock pulse. Parallel transmission is used for small distances.


Figure below shows how parallel transmission works for n =8. Typically, the eight wires are bundled in a cable.


Advantages of parallel transmission:

The advantage of parallel transmission is speed. n bits are transmitted simultaneously with  a single clock. It is n times faster than serial transmission.

Disadvantages of Parallel transmission:

Not a cost effective method for long distance communications as it requires n communication lines to transmit the data stream. 

Serial Transmission

Bits are transmitted serially one after the other.

In serial transmission one bit follows another, only one bit of data is transmitted on each clock.

 We need only one channel rather than n transmission lines to transmit data between two communicating devices.


The advantage of serial over parallel transmission is that with only one communication line reduces the cost of transmission over parallel by roughly a factor of n.



1.      It is slow method as one bit at a time is transmitted. 

2.      As communication within devices is parallel, we require conversion devices at the interfaces.

                             A.    We required parallel to serial converter at the interface between the sender

                             B.    and the channel, and parallel-to-serial converter between the channel and the receiver

Serial transmission occurs in one of two ways:

1.      Asynchronous

2.      Synchronous

Related Questions

Question:     Differentiate between serial and parallel transmission.    [5 marks]