Device-independent access means that the user may interact with the user agent or document with a preferred input (or output) device -- mouse, keyboard, voice, head wand, or other. If, for example, a form control can only be activated with a mouse or other pointing device, someone who is using the page without sight, with voice input, or with a keyboard or who is using some other non-pointing input device will not be able to use the form.
Note: Providing text equivalents for image maps or images used as links makes it possible for users to interact with them without a pointing device. Generally, pages that allow keyboard interaction are also accessible through speech input or a command line interface.