Why is USB faster than serial?

The characteristics and working principle of USB
USB is a universal standard interface used for connecting and transmitting data. It supports hot swapping and can connect various peripheral devices, such as printers, keyboards, mice, cameras, etc. There are multiple versions of the USB standard, including USB 1.0, USB 2.0, USB 3.0, and USB 3.1, each with a different data transfer rate.
USB adopts a serial communication method, which transfers data bit by bit through a single transmission line. It also has the characteristic of time-sharing multiplexing, which means that multiple devices can transmit data through sharing the same line. USB uses differential signal transmission, which means it can better resist electromagnetic interference and provide more reliable connections.
The working principle of USB involves communication between the host and the device. The host is responsible for managing and controlling data transmission, while the device responds to the host's instructions. USB also supports multi-channel transmission, allowing it to handle multiple data streams simultaneously.
The characteristics and working principle of serial communication
Serial communication is a communication method that transmits data bit by bit through a single transmission line. Compared to parallel communication, serial communication can reduce the number of cables and lower the complexity of the system. Serial communication is commonly used in long-distance transmission and environments that combat electromagnetic interference.
The working principle of serial communication involves sending data in bit order and organizing and verifying data using information such as start bit, data bit, check bit, and stop bit. In serial communication, the transmission order of each bit is very important because the receiving end needs to restore data in the correct order.
Why is USB faster than serial?
Parallel transmission vs. serial transmission:
USB uses serial transmission, while some serial communication protocols may still use parallel transmission. Parallel transmission involves transmitting multiple bits simultaneously, but as the number of lines increases, interference and electromagnetic radiation between lines will increase. In contrast, the differential signal transmission and serial mode of USB are more suitable for resisting interference during high-speed transmission.
Differential signal transmission:
USB uses differential signal transmission, which means it sends data and its reverse phase simultaneously. At the receiving end, two signals are subtracted to eliminate some interference. This transmission method makes USB more stable and reliable during high-speed transmission.
Time division multiplexing:
USB supports time-sharing multiplexing, allowing multiple devices to share the same cable for data transmission without interfering with each other. This makes USB more efficient when connecting multiple devices.
Optimization of USB protocol:
The USB protocol has undergone multiple upgrades and optimizations, and different versions of the USB standard support different data transfer rates. The USB 3.0 and USB 3.1 standards introduce higher transfer rates, making USB a faster data transfer method.
Taking into account the above factors, USB is faster than some traditional serial communication methods, especially in scenarios that require high-speed transmission and stable connections. However, it should be noted that the specific transfer rate also depends on the USB standard used and the performance of the device. In practical applications, choosing the appropriate communication method needs to be balanced based on specific needs and environmental conditions.