PS/2 interface function is single, only can be used to connect a keyboard and mouse. Under normal circumstances, the mouse interface is green, purple keyboard interface. PS/2 interface transfer rate slightly faster than a COM interface, but after so many years of use, the vast majority of the Board is still equipped with the interface, but supports the interface of mouse and keyboard less and less, most of the peripheral manufacturers are no longer based on the interface of the peripheral products, more is the introduction of USB interface peripherals products. But it is worth mentioning that, since the interface is widely used, many users prefer PS/2-USB, even using USB adapter plugging into PS/2 use, plus keyboard and mouse for each generation of products are very long, interface still uses very efficient, but in the near future, being completely replaced by USB interface is highly likely.
USB is now the most popular interfaces, you can support up to 127 peripherals, and independent power supply, which is widely used. 500mA of current can be obtained from the motherboard USB interface, support hot plug, truly Plug and play. A USB interface supports both high-speed and low-speed USB peripheral access, connected by a four-core cable, two of which are positive and negative power supply, the other two are data transmission line. High speed transfer speed 12Mbps peripheral, low-speed peripherals at speeds of 1.5Mbps. In addition, the highest transfer rates up to 480Mbps USB 2.0 standard. USB 3.0 has appeared on the motherboard, and has begun to spread.