The key difference between synchronous and asynchronous transmission is that synchronous transmission uses synchronized clocks to transmit data while asynchronous transmission uses flow control instead of using a synchronized clock to transmit data.
Data transmission is the process of sending data from the transmitter to the receiver. There are two types of data transmission known as Parallel Transmission and Serial Transmission. Serial transmission sends one bit at a time, sequentially over the communication channel. Parallel Transmission sends multiple bits over several parallel channels at the same time. Synchronous and asynchronous transmission are two types of serial transmission.
CONTENTS
1. Overview and Key Difference
2. What is Synchronous Transmission
3. What is Asynchronous Transmission
4. Side by Side Comparison – Synchronous vs Asynchronous Transmission in Tabular Form
5. Summary
What is Synchronous Transmission?
In serial transmission, there is a single channel between the sender and the receiver and the bits lined at the sending device for transmission go one after the other sequentially. Serial Transmission further divides into synchronous and asynchronous transmission.
Figure 01: Data Transmission Classification
In this transmission, the transmitter clock and the receiver clock are in synchronization, therefore, they run at the same rate. It transmits block by block or frame by frame at a single time within fixed time intervals. Furthermore, it does not have overhead with extra header and footer bits. In brief, synchronous transmission is efficient, reliable and allows a large amount of data transferring.
What is Asynchronous Transmission?
Asynchronous Transmission, also called as start/stop transmission, sends data from sender to receiver using flow control method. It does not use a clock to synchronize data between the source and the destination.
This transmission sends one character or 8 bits at a time. Before transmission each character it sends the start bit. After sending the character it sends the stop bit. With the character bits and start and stop bits, the total number of bits in 10 bits. In brief, it is a simple, fast and cost-effective transmission method.
What is the Difference Between Synchronous and Asynchronous Transmission?
Synchronous vs Asynchronous Transmission |
|
| Synchronous Transmission is a transmission method that uses synchronized clocks to ensure both the sender and receiver are synchronized to transmit data. | Asynchronous Transmission is a transmission method that sends data using flow control to transmit data between the source and the destination. |
| Efficiency | |
| More efficient | Less efficient |
| Method of Sending Data | |
| Sends blocks or frames of data at a time | Sends one byte or character at a time |
| Cost | |
| Comparatively, high | Cost is low |
| Time Interval | |
| Uses fixed time intervals | Uses arbitrary time intervals |
| Examples | |
| Some examples of synchronous transmission are chat rooms, video conferencing, telephone conversations, etc. | Emails, television, and radios are few examples for asynchronous transmission. |
Summary – Synchronous vs Asynchronous Transmission
Usually, more data passes per unit time in synchronous transmission than in the asynchronous transmission. The difference between synchronous and asynchronous transmission is that synchronous transmission uses synchronized clocks to transmit data while asynchronous transmission uses flow control instead of using the synchronized clock to transmit data. Overall, synchronous transmission is more reliable and efficient than asynchronous transmission.
Reference:
1.Wikipedia, Wikimedia Foundation, 22 Apr. 2018. Available here
2.Tutorials Point., Tutorials Point, 8 Jan. 2018. Available here
Image Courtesy:
1.’Data transmission’By Department4 – Own work, (CC BY-SA 4.0) via Commons Wikimedia