"Object name, value, role, state"
Access technologies need to be able to identify accurately all the different types of controls and their labels, such as edit fields, buttons, checkboxes, radio buttons and boxes containing drop-down lists.
This is information that is needed for navigation by voice recognition software to enable a user navigating by voice alone to 'say what they see' and move to the appropriate control.
On the other hand, screen reader users need to know from the label what a field contains and, from the role (or type of control), whether to interact with the software by typing text, pressing Enter or Spacebar, or using cursor arrows.
Within Windows, Microsoft offers a useful tool called Object Inspector that can indicate this whether this programmatical information is present and accurate. More information about this tool is given in the Software Access Centre section on testing and evaluation.
Visible focus
This is the 'I-beam', highlight or outline that indicates which screen element has the input focus, ie where an action from the keyboard will take place. This is essential information for a keyboard or voice input user who doesn't have the luxury of just moving the mouse and clicking.
When the focus is an I-beam within text, a screen reader can pick up its location to enable a blind person to compose and edit text successfully. When the focus is not a text cursor, other information about the focus is also conveyed via a screen reader to someone who cannot see the screen, for example 'list item', 'checkbox' or 'button'.
Compatibility with access technologies
This is mainly achieved by using standard accessibility services provided by the operating system and software toolkits. This should allow the information about the programmatical interface described in this section to be picked up by access technology without further effort by the programmer or developer. Creating new controls or tinkering with how standard controls work usually diminishes accessibility and usability.
There are some trial versions and some free access tools that can help give an indication of whether this compatibility has been achieved. These include magnification software, voice recognition and speech output systems, both built into the operating system and available online to download.
Further information about access technology.
There are risks associated with using these tools, which do not always give an accurate representation of how a disabled user would use a software interface. It is always preferable to seek out expert assistance when looking into compatibility with access technologies.