Difference between Serial and Parallel Transmission

The process of sending data between two or more digital devices is known as data transmission. Data is transmitted between digital devices using one of the two methods − serial transmission or parallel transmission.

In serial transmission, data bits are sent one after the other across a single channel. Parallel data transmission distributes numerous data bits through various channels at the same time.

What is Serial Transmission?

A serial transmission transfers data one bit at a time, consecutively, via a communication channel or computer bus in telecommunication and data transmission. On the other hand, parallel communication delivers multiple bits as a single unit through a network with many similar channels.

  • 8-bits are conveyed at a time in serial transmission, with a start bit and a stop bit.

  • All long-distance communication and most computer networks employ serial communication.

  • Serial computer buses are becoming more common, even across shorter distances, since newer serial technologies' greater signal integrity and transmission speeds have begun to outperform the parallel bus's simplicity advantage.

  • The majority of communication systems use serial mode. Serial networks may be extended over vast distances for far less money since fewer physical wires are required.

What is Parallel Transmission?

Parallel communication is a means of transmitting multiple binary digits (bits) simultaneously in data transmission. It differs from serial communication, which sends only one bit at a time; this distinction is one method to classify a communication channel.

  • A parallel interface comprises parallel wires that individually contain data and other cables that allow the transmitter and receiver to communicate. Therefore, the wires for a similar transmission system are put in a single physical thread to simplify installation and troubleshooting.

  • A large amount of data must be delivered across connection lines at high speeds that match the underlying hardware.

  • The data stream must be transmitted through "n" communication lines, which necessitates using many wires. This is an expensive mode of transportation; hence it is usually limited to shorter distances.

Difference between Serial and Parallel Transmission

The following table highlights the major differences between Serial and Parallel Transmission −

Serial Transmission
Parallel Transmission
Serial Transmission is the type of transmission in which a single communication link is used to transfer the data from one end to another.
Parallel Transmission is the mode of transmission in which multiple parallel links are used that transmit each bit of data simultaneously.
Bit transmission
In case of Serial Transmission, only one bit is transferred at one clock pulse.
In case of Parallel Transmission, 8-bits transferred at one clock pulse.
Cost Efficiency
As single link is used in Serial Transmission, it can be implemented easily without having to spend a huge amount. It is cost efficient.
Multiple links need to be implemented in case of Parallel Transmission, hence it is not cost efficient.
As single bit gets transmitted per clock in case of Serial Transmission, its performance is comparatively lower as compared to Parallel Transmission.
8-bits get transferred per clock in case of Parallel transmission, hence it is more efficient in performance.
Serial Transmission is preferred for long distance transmission.
Parallel Transmission is preferred only for short distance.
Serial Transmission is less complex as compared to that of Parallel Transmission.
Parallel Transmission is more complex as compared to that of Serial Transmission.


When there is data transfer between computers/laptops there could be two types of transmission of data, i.e., Serial or Parallel. Serial Transmission uses a primary circuit, while Parallel Transmission uses a circuit that is quite complicated. In this article, we distinguished between Serial and Parallel transmission on the basis of their different characteristics.