What is the difference between USB and RS232?

Physical interfaces and connection methods
USD:
USB is a universal and high-speed serial bus standard used to connect computers and their external devices. The USB interface is hot swappable, which means you can insert or remove USB devices while the computer is running without the need to restart the computer. USB interfaces are usually compact, with different shapes such as Type-A, Type-B, Micro USB, and USB-C.
RS232:
RS232 is a traditional serial communication standard widely used to connect computers and serial devices. RS232 typically uses 9 or 25 pin connectors, and when connecting, it is necessary to ensure that the device is turned off to prevent hardware damage. Unlike USB, RS232 typically does not support hot swapping.
Voltage level and signal transmission
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USB uses differential signal transmission, where the difference between two relative levels represents data bits. USB typically operates at a voltage level of 5V and has high anti-interference and reliability. In addition, the USB interface can provide power supply, so it can charge connected devices.
RS232:
RS232 uses single ended signal transmission, where data bits are represented by a single voltage level. RS232 typically operates at lower voltage levels, typically+12V and -12V. Due to the use of single ended signals, RS232 may have limited anti-interference and transmission distance compared to USB.
Data transmission speed
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USB offers different versions, including USB 1. x, USB 2.0, USB 3.0, and USB 3.1, each with different data transfer speeds. USB 3.0 and 3.1 versions support higher speeds, up to 5 Gbps or higher. USB is commonly used for high-speed data transmission and is suitable for connecting various devices, from printers to external hard drives.
RS232:
RS232 typically has a lower data transmission speed, with the most common speed being 115200 bps. Due to its traditional nature, RS232 is commonly used to connect low-speed devices that do not require large amounts of data transmission, such as serial printers or control devices.
Application areas and device compatibility
USD:
USB has become a universal standard widely used in various devices, including printers, cameras, keyboards, mice, mobile devices, etc. Almost all modern computers are equipped with USB interfaces, making USB the preferred standard for device connectivity.
RS232:
RS232 is still widely used in some old devices, especially in some industrial automation and control systems. However, due to its traditional nature and some limitations, the use of RS232 in modern computers and consumer electronic devices is gradually decreasing.