Keyboard and mouse

Compared to the high-speed interfaces discussed earlier in this chapter, the bandwidth requirements for a keyboard and mouse are quite modest. These devices are the sole input methods used by the human operator in most computer configurations, and thus are only required to operate at the speed of human actions. Even the fastest typist can only press one or two dozen keys per second.

Keyboard

A mechanical computer keyboard consists of a collection of keys, each of which activates an electrical momentary switch. A standard full-size keyboard typically contains 104 keys including the arrow keys, control keys (Home, Scroll Lock, and so on), and the numeric keypad. Modern keyboards commonly use a USB cable for connection to the computer or connect wirelessly.

Because the bandwidth requirements for human interaction are so low, some computer motherboards provide a slower USB 2.0 port for keyboard connection while offering higher-performance USB 3.2 or faster...