The key difference between Serial and Parallel Communication is that in serial communication data transmission occurs bit by bit at a time while in parallel communication multiple bits transmit at a time. However, though the data is transmitted bit by bit, serial communication is fast for long distances and high frequencies. But, parallel communication is fast for short distances and low frequencies but slower for long distances and high frequencies.
In data communication, the data travels from the source device or sender to the destination device or the receiver. There are multiple devices connected to share data. Serial and parallel communication are two ways of transmitting data from the sender to receiver.
CONTENTS
1. Overview and Key Difference
2. What is Serial Communication
3. What is Parallel Communication
4. Side by Side Comparison – Serial and Parallel Communication in Tabular Form
5. Summary
What is Serial Communication?
In serial communication, there is a single channel between the sender and receiver. In this method, the bits line up at the receiver, and each bit travels through the channel one at a time.
Figure 01: Data Communication
Even though, it appears that serial communication is slower because of transferring one bit at a time, in practice it is fast. The data transmission speed is higher especially at high frequencies and when there are long distances. Furthermore, as there is only one channel or a line, the cost of this communication is minimum. In brief, serial communication is simple, straightforward and accurate.
What is Parallel Communication?
In parallel communication, multiple bits sent through the channels or buses simultaneously. Assume that there are three bits to transmit. Then, they will go through three separate lines from sender to receiver.
For short distances and low frequencies, the parallel communication is fast because several bits transmit at a time. However, when increasing the distance and the frequency, it causes some issues in parallel communication. One major issue is crosstalk. It is the possibility of bits skipping into other channels or buses. This can result in making the output at receiver end different from the sender’s. Another issue is skewing. In other words, the receiver has to wait till the slowest bit arrives. Therefore, even though parallel communication is faster for short distances and low frequencies, the speed gets lower for long distances and high frequencies due to the above issues. In brief, this communication is unreliable and is a complicated transmission method.
What is the Difference Between Serial and Parallel Communication?
Serial vs Parallel Communication |
|
| The process of sending data one bit at a time, sequentially over a communication channel or a computer bus. | The process of sending multiple bits as a whole on a link with several parallel channels or computer buses. |
| Required Number of Lines | |
| Uses a single line to send data | Uses several lines to transmit data |
| Speed | |
| Slow for short distances and low frequencies but higher in long distances and high frequencies | Fast for short distance and low frequencies but slower in long distances and high frequencies |
| Error and Noise | |
| Error and Noise are minimum | Error and noise are high |
| Nature | |
| Simple and straightforward | Unreliable and complicated |
| Cost | |
| Cost is comparatively lower | Cost is higher in comparison |
Summary – Serial vs Parallel Communication
Both serial and parallel communication are two types of data transmission. The difference between Serial and Parallel Communication is that in serial communication, the data transmission occurs bit by bit at a time while in parallel communication, it is multiple bits transmission.
Reference:
IGCSE Computer Science – Serial and Parallel Data Transfer, James Waring, 11 Dec. 2016. Available here
2.Wikipedia, Wikimedia Foundation, 15 May 2018. Available here
Image Courtesy:
1.’1172193′ by eak_kkk (CC0) via Pixabay