United States Department of Veterans Affairs
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Training for Testing Software for 508 Compliance

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Testing for §1194.21 (b): Interoperability

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Introduction, continued

Operating System-Accessibility Feature Interoperability

Checkpoint 1: Are all of the documented accessibility options that are available via the operating system still able to be activated and work correctly?

Operating systems have built-in features that allow users to interact with the applications they are running. In Windows, these features include font adjustments, magnification and high contrast display settings and cursor blink rate settings, which assist persons with visual impairments; the Sound Sentry feature, which alerts deaf or hearing impaired users when an audio cue has occurred; and the Onscreen Keyboard, Sticky Keys, Filter Keys and Mouse Keys features, which assist users who have dexterity and motor impairments. This checkpoint also includes access to sound- and speech-generating hardware and software that are necessary for screen reader users.

You can find most of the built-in accessibility features of Windows on the Control Panel, under Accessibility Options. The best way to test compatibility for these features is to try them out yourself. Compare how the features work in the application you are testing to how they work in a standard Windows application such as Windows Explorer.

Windows also has accessibility utilities in the Accessories folder in All Programs. These are the Onscreen Keyboard, a limited screen-reading application called Narrator and a screen magnification utility called Magnifier. Of these, only the Onscreen Keyboard should be considered an AT for testing purposes.

People with severe motor impairments who use alternative inputs, such as joysticks, switches, or technologies that track eye blinks or eye gaze, may use the Onscreen Keyboard.

Narrator and Magnifier were not designed to be as versatile as many of the third-party assistive technologies that are available. Although they can be useful as a quick reality check for some accessibility issues, they should not be used as the primary means of AT testing.

Within the operating system, there are three areas of interoperability that are critical for users of assistive technology; they are sound, display settings and the keyboard and mouse. In this section you will learn more about each of these.


The sound features listed below provide functionality that is important to users of AT. Please note that the Show Sounds feature relies on specifically-designed application programming interfaces (APIs) that may not be utilized in all applications. If you are aware that the application supports this functionality, then you should test that it works. If not, enable the features in the Sounds tab and confirm that the application continues to operate as expected.

  • Audio Output. Be sure that the application does not turn off sound automatically.
  • Toggle Keys. Although this setting is grouped with the Keyboard Accessibility settings, its function is to provide audible signals when a toggleable key (like Num Lock or Caps Lock) is on or off. Be sure that the application does not interfere with a user's ability to use this feature.
  • Sound Sentry. If the application generates system sounds for audible cues, be sure that it works with Windows Sound Sentry, which flashes part of the screen to notify the user that a sound event has occurred. Also make sure that the visual display of the application does not interfere with a user's ability to set the parameters for Sound Sentry or the user's ability to see the alert. If you do not believe the application supports Sound Sentry functionality, be sure that having Sound Sentry enabled does not change how the application works.
  • Show Sounds. If the application utilizes the APIs that support this feature, make sure that the application does not interfere with the use of Show Sounds, and provides appropriate textual and/or visual information to allow the Show Sounds utility to work correctly. If the application does not support Show Sounds APIs, be sure that the application still functions as expected when Show Sounds is enabled.
  • Be sure that visual cues are provided when audio cues signal errors or successful completion of actions. More information about this is provided in the Electronic Forms module.

Display Settings

Make sure that the application does not interfere with a user's ability to set and maintain display settings such as High Contrast and cursor appearance and blink rate.

Keyboard and Mouse

These four features also provide functionality that is important to users of AT.

  • Sticky Keys. Make sure that the application does not interfere with a user's ability to apply Sticky Keys settings. Sticky Keys allows users to press keys in sequence that would normally be held down simultaneously. This is useful for people with dexterity impairments.
  • Filter Keys. Make sure that the application does not interfere with a user's ability to apply Filter Keys settings. Filter Keys sets parameters that will ignore unintended short or repeated keystrokes. This is useful for people with certain motor impairments.
  • Show Extra Keyboard Help in Programs. When this setting is checked, keyboard help information should be made available to the user. Make sure that the application makes use of this feature where applicable, and does not interfere with its use in other programs.
  • Mouse Keys. The Mouse Keys utility allows users to simulate mouse movement with the numeric keypad of their keyboard. This can be useful for people with certain motor impairments. Be sure that the application does not interfere with a user's ability to use this feature.

AT Compatibility

Checkpoint 2: Does the application allow assistive technology to function without interference?

As noted earlier, and in other parts of this training, it is important that applications not interfere with the proper functioning of an AT. This includes proper compatibility with screen enlargement programs and screen readers.

  • Screen Enlargement. Make sure that color, cursor enhancement, focus tracking and enlargement features of screen enlargement software work as intended with the application's interface.
  • Screen Readers. Make sure that there are no sound-related parameters set that prevent users from using their screen readers. This includes making sure that security settings for documents are set to allow them to be read aloud by AT.
  • Alternative Input. Make sure that the application permits users to use the input technology they require and does not override settings used by speech input technologies, on-screen keyboards, or other types of input hardware or software, such as speech recognition software.

If you have specific questions or need help with an issue, please contact the VHA Section 508 Office.

Select Next for some examples.

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