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Tactilely discernible keys

Hardware Self Contained, Closed Products checkpoint 2.2

A user who is blind or visually impaired will have difficulty distinguishing flat membrane keys or buttons unless there is a tactile distinction between the keys. Users need to be able to identify the keys without activating them.

Rationale

Techniques

Testing

 

Rationale

A user who is blind or visually impaired will have difficulty distinguishing flat membrane keys or buttons unless there is a tactile distinction between the keys. Users need to be able to identify the keys without activating them.

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Development techniques

Use one or more of the following techniques to meet Checkpoint 2.2 from the IBM Hardware Self Contained Closed Products Accessibility Checklist:

  • Use a QWERTY keyboard, or an ABC keyboard, etc.
  • Use a 12 key telephone keypad, or a 17 key numeric keypad.
  • Provide tactile labels (nibs) on home keys (e.g. F and J on QWERTY keyboard,5 key on the numeric keypad). Tactile labels should be raised 1/32". It is better to provide the tactile landmark on the key rather than above or below the key. Distinguish the home key(s) with a different concave depth.
  • Use spacing or shapes to distinguish keys or groups of keys. Provide ridges around the keys. Provide convex keys. Provide a bump or depression on the key.
  • Provide a key guard or overlay option.

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Testing techniques

Test the hardware to ensure that it complies with accessibility requirements.

Tools

You will need the following tools to test this checkpoint:

  • Feeler gauge
  • Calipers
  • Ruler

Techniques

One or more of the following techniques are required to verify this checkpoint:
Action Result
1. Use a QWERTY or ABC keyboard.

This can be accomplished by touching or viewing the keyboard. 		Pass:
  • The keyboard is a QWERTY, ABC, or other standard keyboard. All keys can be uniquely identified without activating it.


Fail:
  • The keyboard is not a QWERTY, ABC or other standard keyboard.
2. Use an industry standard 12 key telephone or and industry standard 17 key numeric keypad.

Verify through software test case. 		Pass:
  • I/O is done with an industry standard 12 key telephone pad,
  • or an industry standard 17 key numeric keypad.


Fail:
  • I/O is not done with an industry standard 12 key telephone pad,
  • nor an industry standard 17 key numeric keypad.
3. Using either a feeler gauge or calipers check that the Home keys have tactile labels (nibs) which are raised 1/32". (e.g. F and J on a QWERTY keyboard, or the 5 key on the numeric keypad).

Using a ruler determine that the concave depth of the home keys is different than the concave depth of the other keys. 		Pass:
  • The home key(s) have tactile labels (nibs) which are raised 1/32 of an inch.
  • The home key(s) have a different concave depth than the other keys.


Fail:
  • The home key(s) have no tactile labels (nibs).
  • The home key(s) have tactile labels, but they are not raised at least 1/32 of an inch.
  • The home key(s) have the same concave depth as the other keys.
4. Check that spacing or shape can be used to distinguish keys.Check that keys have ridges around them.

Check to see if some keys are convex.

Check to see that some keys have a bump or depression on the key. 		Pass:
  • Spacing or shape can be used to distinguish keys uniquely, or
  • Keys have ridges around them, or
  • Keys are convex or,
  • Keys have bumps or depressions.


Fail:
  • Keys can not be distinguished by spacing or shape, nor,
  • Keys have no ridges, nor,
  • Keys are not convex, nor,
  • Keys have no bumps or depressions.
5. Check for a key guard or overlay.
Pass:
  • There is a key guard or overlay.


Fail:
  • There is no key guard or overlay.

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©2001, 2008 IBM Corporation

Last updated January 30, 2008.

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