Do not interfere with keyboard accessibility features built into the operating system.
Rationale
The Windows operating system, CDE/Motif Unix systems, OS X, and iOS systems have a set of accessibility options which enable users with disabilities to customize system wide settings to improve accessibility. For example, a Windows user with a physical disability may not be able to press multiple key stroke sequences, such as Ctrl+Alt+Delete, simultaneously. Setting the Sticky Keys option enables the user to press and release the keys to invoke the desired function. For example, the user can press and release the Shift key 5 times, then press and release Ctrl, then Alt, then Delete to restart the Windows operating system.
Keyboard accessibility options make it possible for people with a variety of disabilities to use their computer. If the application software interferes with these options, some users may find their system unusable.
On Unix systems, they are part of the AccessX package. On Apple OS X systems, they are in System Preferences as part of Universal Access. On iOS systems they are available in Settings, General, Accessibility.
Required development techniques
- Examples for Windows developers
- Examples for Unix, CDE/Motif developers
- Examples for OS X developers
- Examples for iOS developers
The following techniques are the minimum required to meet Checkpoint 1.2 from the IBM Software Accessibility Checklist:
- Do not disrupt or disable documented operating system features for keyboard accessibility.
- Do not define application keyboard shortcut keys that interfere with documented shortcut keys for operating system accessibility features.
Examples for Windows developers
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Do not disrupt or disable documented operating system features for keyboard accessibility.
Example 1
On Windows, the user may customize the Accessibility Options available through the Control Panel settings.
- StickyKeys enable users to press multiple key strokes like Ctrl-Alt-Delete by pressing one key at a time.
- FilterKeys enable users to slow the keyboard repeat rate. Software must support the user's setting for the repeat rate.
- ToggleKeys enable users to hear tones when the Caps lock, Num Lock or Scroll Lock keys are pressed.
- High contrast support enables users to set the default system color and font scheme to one that is easier to read.
- MouseKeys enable users to move the mouse pointer using the arrow keys on the keyboard.
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Do not define application keyboard shortcut keys that interfere with documented shortcut keys for operating system accessibility features.
Example 2
The following is a list of the accessible keyboard shortcut keys on Windows:
- Keyboard shortcut to enable and disable StickyKeys is to press the Shift key 5 times.
- Keyboard shortcut to enable and disable FilterKeys is to hold down the right Shift key for 8 seconds.
- Keyboard shortcut to enable and disable ToggleKeys is to hold down the Num Lock key for 5 seconds.
- Keyboard shortcut to enable and disable High Contrast is to press the Left-Alt key+Left-Shift key+PrintScreen key.
- Keyboard shortcut to enable and disable MouseKeys is to press the Left-Alt key+Left-Shift key+Num Lock key.
Examples for Unix, CDE/Motif developers
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Do not disrupt or disable documented operating system features for keyboard accessibility.
Example 3
- Sticky Keys enable users to press multiple key strokes like Ctrl-Alt-Delete by pressing one key at a time.
- CDE/Motif systems enable users to slow the keyboard repeat rate through the Slow Keys and Repeat Keys features.
- Toggle Keys enable users to hear tones when the Caps lock, Num Lock or Scroll Lock keys are pressed. CDE/Motif systems provide Toggle Keys function but do not provide a keyboard shortcut to enable and disable it.
- Mouse Keys enable users to move the mouse pointer using the arrow keys on the keyboard.
- CDE/Motif systems reserve several key sequences. Six consecutive clicks of the Control key will enable and disable screen-reader numeric keypad functions. Six consecutive clicks of the Alt key are reserved for future AccessX use.
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Do not define application keyboard shortcut keys that interfere with documented shortcut keys for operating system accessibility features.
Example 4
- Keyboard shortcut to enable and disable Sticky Keys is to press the Shift key 5 times.
- The keyboard shortcut to enable and disable Slow Keys and Repeat Keys is to hold down either Shift key for 8 seconds.
- Toggle Keys function does not have a keyboard shortcut to enable and disable defined.
- Mouse Keys function does not have an accelerator key sequence to enable and disable defined.
- CDE/Motif systems reserve several key sequences. Six consecutive clicks of the Control key will enable and disable screen-reader numeric keypad functions. Six consecutive clicks of the Alt key are reserved for future AccessX use.
Examples for OS X developers
On Apple OS X systems accessibility is found in System Preferences under Universal Access.
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Do not disrupt or disable documented operating system features for keyboard accessibility.
Example 5
- Sticky Keys enable users to press multiple key strokes like Ctrl-Alt-Delete by pressing one key at a time.
- Slow Keys enable users to slow the keyboard (similar to RepeatKeys on Windows).
- Toggle Keys support is not provided on an OS X system.
- Mouse Keys enable users to move the mouse pointer using the arrow keys on the keyboard.
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Do not define application keyboard shortcut keys that interfere with documented shortcut keys for operating system accessibility features.
Example 6
- Keyboard shortcut to enable and disable Sticky Keys is to press the Shift key 5 times.
- Slow Keys are enabled on an OS X system through the Universal Access Control Panel.
- Toggle Keys support is not provided on an OS X system.
- Keyboard shortcut to enable and disable Mouse Keys is Command-Shift-Clear.
Examples for iOS developers
On iOS systems the Accessibility options are part of the System settings. The iOS soft keyboard displayed on the screen does not support key repeat, except on delete and the repeat rate is not adjustable. The Bluetooth keyboard supports repeat, but the rate is not adjustable. Bluetooth keyboard pairing is done using System, Keyboard.
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Do not disrupt or disable documented operating system features for keyboard accessibility.
Example 7
- Triple-click home is an option that can be set to turn VoiceOver on or off with Triple-click.
- Keyboard access through a paired Bluetooth keyboard is done through standard pairing under System, keyboard. When a keyboard is paired and VoiceOver is turned on, navigation is possible with the keyboard. See VoiceOver navigation keys using a paired Bluetooth keyboard. (link resides outside of ibm.com)
- Slow Keys, Toggle Keys, and Mouse Keys are not enabled on a keyboard attached by Bluetooth.
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Do not define application keyboard shortcut keys that interfere with documented shortcut keys for operating system accessibility features.
Example 8
- Do not interfere or override Apple standard keyboard navigation keys for VoiceOver. See VoiceOver navigation keys using a paired Bluetooth keyboard. (link resides outside of ibm.com)
Required test techniques
Test the software to ensure that it complies with accessibility requirements.
- Required test software
- Windows test techniques
- Unix test techniques
- OS X test techniques
- iOS test techniques
Required test software
No additional software is required to test this checkpoint.
Windows test techniques
The following techniques are required to verify this checkpoint:
Action | Result |
---|---|
1. Test with StickyKeys enabled.
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Pass: Multiple key stroke sequences can be activated by pressing and releasing each key sequentially. Fail: Multiple key stroke sequences can only be activated by pressing the keys simultaneously. |
2. Test with FilterKeys enabled.
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Pass: Only one letter is displayed on the screen when you press and hold a key. Fail: Multiple copies of a letter are displayed on the screen when you press and hold a key. |
3. Test with ToggleKeys enabled.
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Pass: An audio tone sounds when the Caps Lock, Num Lock, and Scroll Lock keys are pressed. Fail: No audio tone sounds when the Caps Lock, Num Lock, and Scroll Lock keys are pressed. |
4. Test with MouseKeys enabled.
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Pass: The mouse pointer can be moved using the arrow keys. Fail: The mouse pointer does not move when using the arrow keys. |
5. Test with HighContrast enabled.
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Pass: The color scheme for the displayed information is changed to the HighContrast scheme. Fail: The color scheme for the displayed information is not changed to the HighContrast scheme, or not fully changed to the high contrast scheme. |
Unix test techniques
The following techniques are required to verify this checkpoint:
Action | Result |
---|---|
1. Test with Sticky Keys enabled.
|
Pass: Multiple key stroke sequences can be activated by pressing and releasing each key sequentially. Fail: Multiple key stroke sequences can only be activated by pressing the keys simultaneously. |
2. Test with Repeat Keys enabled.
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Pass: Only one letter is displayed on the screen when you press and hold a key. Fail: Multiple copies of a letter are displayed on the screen when you press and hold a key. |
3. Test with Toggle Keys enabled.
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Pass: An audio tone sounds when you press the Caps Lock, Num Lock, and Scroll Lock keys. Fail: No audio tone sounds when you press the Caps Lock, Num Lock, and Scroll Lock keys. |
4. Test with Mouse Keys enabled.
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Pass: The mouse pointer can be moved using the arrow keys. Fail: The mouse pointer does not move when using the arrow keys. |
OS X test techniques
The following techniques are required to verify this checkpoint:
Action | Result |
---|---|
1. Test with Sticky Keys enabled.
|
Pass: Multiple key stroke sequences can be activated by pressing and releasing each key sequentially. Fail: Multiple key stroke sequences can only be activated by pressing the keys simultaneously. |
2. Test with Slow Keys enabled.
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Pass: Only one letter is displayed on the screen when you press and hold a key. Fail: Multiple copies of a letter are displayed on the screen when you press and hold a key. |
4. Test with Mouse Keys enabled.
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Pass: The mouse pointer can be moved using the arrow keys on the keyboard. Fail: The mouse pointer does not move when using the arrow keys on the keyboard. |
iOS test techniques
The following techniques are required to verify this checkpoint:
Action | Result |
---|---|
1. Test with VoiceOver and a Bluetooth keyboard attached.
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Pass: All documented VoiceOver keyboard navigation commands work with the application. Fail: One or more VoiceOver keyboard assignments fail to work. |
©2009, 2013 IBM Corporation
Last updated January 28, 2013.