7 - Device Interfacing

Hardware design and interfacing is the process by which hardware devices are designed and built to communicate and interact with the computer. For example, consider the mouse on a computer. The mouse sends positional information in terms of how much movement has taken place horizontally and vertically by first measuring it and then communicating the information to the computer. The measurement is done using a ball and rollers for a mechanical mouse and a laser for an optical mouse.  The positional information is then communicated to the computer using on and off electrical signals. Different signaling methods can used to send information to the computer and receive information from the computer. For successful communication to take place, a common standard of information exchange is needed between the computer and the peripheral device. There are several standards that enable communication to take place. For example the standard for the video interface is not the same as the standard for a USB interface. The concept of hardware communication standards is similar to human communication. In the computer world, communication can take place using different methods just like communication between people can be accomplished using different languages, but communication cannot take place if the computer and the devices are using different standards. This is similar to the idea that meaningful communication is not possible between someone who speaks English only and someone who speaks Swahili only.