A serial port is a serial interface, which is also a COM interface. It is a 9-pin or 25-pin D-type interface, which can be used by connecting the mouse to the serial port of the computer host. Its advantage is that it has the largest range of applications and models, but its disadvantage is that the data transmission rate of serial communication is too low, and the middle and high-grade mouse can not play its high performance advantage and does not support hot plug. In the latest BTX motherboard specification, the serial port has been cancelled. With the popularization of BTX specification, serial mouse will be gradually eliminated.
PS/2 interface is the most common mouse interface at present, which was originally patented by IBM, commonly known as "small mouth". This is a special interface for mouse and keyboard, which is a 6-pin circular interface. But the mouse only uses four pins to transmit data and power, and the other two pins are empty. The transmission rate of PS/2 interface is slightly faster than that of COM interface, and it is the standard interface of ATX motherboard. It is one of the most widely used mouse interfaces at present, but it still can't give full play to the performance of high-end mice, and it doesn't support hot plug. In the BTX motherboard specification, this is also the interface that will be eliminated soon.
USB is the abbreviation of English universal serial bus, which means "universal serial bus" in Chinese. Its maximum data transmission rates are 12Mbps and 480Mbps, respectively, and it is a high-speed universal interface. This is a new mouse interface. Compared with the first two interfaces, it has the advantage of very high data transmission rate, which can fully meet the requirements of various mice in terms of refresh rate and resolution, so that all kinds of middle and high-end mice can give full play to their performance and support hot plug.