It might be assumed that common features
address only less severe functional limitations, and that people whose
disabilities are severe cannot find products that meet their needs.
This is often true; for example, slightly larger characters or slightly
greater volume may meet the needs of people with mild vision or hearing loss
respectively.
But it is not the case for a certain set
of access features. The very
presence of the common features listed below – generally examples of the
power of redundancy – may make products equally accessible to people with mild
or severe disabilities:
Tones indicating functions or status.
On-screen operation and activity display.
Keys identifiable by touch (nib, shape, raised letters, etc.).
It is the features that offer improved performance along a continuum that more often serve only consumers with more mild or moderate disabilities. These include volume control, high-contrast displays, and larger buttons.