APPENDIX C: Example Strategies for Addressing Guidelines

This appendix provides example strategies and notes to assist in understanding the guidelines and as a source of ideas for alternate strategies for achieving them. The strategies, and notes here are not mandatory in nature. The manufacturer is not required to incorporate all of these strategies or any specific strategy. They are free to use these or other strategies in addressing the guidelines. The listing below is not comprehensive. Nor does following these example strategies guarantee an accessible product. For a comprehensive listing of all of the published strategies to date, as well as for further information and links to on-going discussions the reader is referred to the Access Board's web page at: http://www.access-board.gov and the National Institute on Disability and Rehabilitation Research's Rehabilitation Engineering Center on Access to Telecommunications System's strategies web page which can be found at: http://trace.wisc.edu/telecom.


5.3.1. Input, Control and Mechanicals


I-1: Locate, Identify, and Operate Controls without Vision

Guideline: Where readily achievable, product input, control and mechanical functions shall be fully operable via at least one mode whose components are locatable, identifiable, and accurately operable without requiring the user to see.

Rationale: Individuals with severe visual disabilities or blindness cannot locate or identify controls, latches, input slits etc. by sight or operate controls that require sight.

Goal: All individuals, regardless of onset of blindness, will be able to accurately and efficiently operate products without assistance.

Problems: Individuals who cannot see must use either touch or sound to locate and identify controls. If a product uses a flat, smooth touch screen or touch membrane, the user without vision will not be able to even locate the controls without auditory or tactile cues. Once the controls have been located, the user must then be able to tell what the functions of the controls are. Finally, they must be able to operate the controls. Individuals who have low vision or are blind cannot accurately operate some types of controls which require vision for use. These include mice, trackballs, dials without markings or stops, and push-button controls with only one physical state, where the only indication of the setting is visual.

Example Strategies for Making Controls Locatable and Identifiable and for Orienting the User:

If you use buttons on your product, making them discrete buttons which can be felt allows a person to locate them tactilely. If you are using a flat membrane keyboard, putting a raised edge around the control areas or buttons makes it possible to tactilely locate the keys. Once an individual locates the different controls, they need to identify what they are. If you have a standard number pad arrangement, putting a nib on the "5" key may be all that is necessary for identifying the numbers. On a QWERTY keyboard, putting a tactile nib on the "F" and "J" keys allows a touch typist who is blind to easily locate their hands on the keys. Providing distinct shapes for keys can either indicate their function or make it easy to tell them apart. Providing braille labels for keys and controls allows individuals who know braille to figure out what the controls are for. Providing large raised letters can work for short labels on large objects. Where it is not possible to use raised large letters, you may be able to incorporate a voice mode which announces keys when pressed, but does not activate them. This would allow people to turn on the voice mode long enough to explore and locate the item they are interested in, then release the voice mode and press the control. If it is an adjustable control, voice confirmation of the status may also be important.

For connectors, either provide a tactile indication as to the way the plug should be oriented or use orientation-independent or self-orienting plugs. Wireless connection strategies, which eliminate the need to orient or insert connectors, also solves the problem.

Avoiding buttons that are activated when touched will allow an individual to explore the controls in order to find the desired button. If you cannot avoid touch-activated controls (for example, on a touch screen), you can provide an alternate mode where a confirm button is used to confirm selections (for example, items are read when touched, and activated when the confirm button is pressed). It is also a good idea to make all actions reversible, or require confirmation before executing non-reversible actions.

Example Strategies for Creating Controls which can be Used without Vision

Once controls have been located and users know what the functions of the controls are, they must be able to operate the controls. Individuals who have low vision or blindness cannot accurately operate some types of controls which require vision for use. These include mice, track balls, dials without markings or stops, and push-button controls with only one state where the only indication of the position or setting of the control (mouse, pointer, etc.) is visual.

Providing a rotational or linear stop and tactile or audio detents is one strategy that can be used. Another is to provide keyboard or discrete push-button access to the functions. If the product has an audio system and microprocessor, audio feedback of the setting may be used. For simpler devices, tactile markings may be sufficient. Controls can also be shaped in a fashion that they can easily be tactilely read (e.g., a twist knob shaped like a pie wedge). If using keys, particularly keys which do not have any physical travel, some type of audio and tactile feedback should be provided so that the individual knows when the key has been activated. If the key is a two-state key (on/off), use a key that is physically different (a toggle switch or a push-in/pop-out switch), so the person can tell what state it is in by feeling it.

If you have an optional voice mode for operating the product a simple "query" mode could be provided, which would allow the individual to find out both the function and state of a switch without actually activating it.

In many cases, there may be other design considerations which make the optimal mode of operation for someone who is sighted something which would not be easily operated by someone without vision (e.g., use of a touchscreen or mouse). In this case, the primary strategy may be to provide a closely linked parallel method for efficiently achieving the same results (e.g., keyboard access) if you have keyboard "SpeedList" access for touchscreens, etc.

Compatibility with assistive devices: See also guidelines dealing with compatibility with software and hardware assistive technologies.


I-2: Operate with Low Vision without Requiring Audio

Guideline: Where readily achievable, the product input, control and mechanical functions shall be fully operable via at least one mode which is operable by individuals who have low vision but are not legally blind, which does not rely on audio output.

Note: 20/70 after correction is the beginning of low vision; 20/200 after correction is the beginning of legal blindness; a field of vision of less than 20 degrees after correction also constitutes legal blindness.

Rationale: Individuals with severe visual disabilities often also have severe hearing disabilities (especially older users) and cannot rely on audio access modes commonly used by those who are blind.

Problem/Objective: For individuals who have low vision and who also have hearing impairments or who are deaf, many of the auditory strategies used by individuals who are blind cannot be used. Tactile strategies are still quite useful, except for braille which few people with low vision know, especially individuals who are older. The objective here, therefore, is to maximize the number of people who can use their residual vision combined with tactile senses to operate the product. It should be noted, however, that individuals with diabetes who are losing their vision also lose fine tactile sensation in their fingertips, although more pronounced tactile information (e.g., the shape of a large knob or strong tactile detents) can be felt.

Goal: Anyone who has low vision can use products, even if they have no useful hearing.

Example non-auditory strategies for maximizing usability for people with low vision:

Strategies for addressing this guideline basically revolve around making the information on the product easier to see. This includes using high-contrast print symbols and visual indicators, minimizing glare on the display and control surfaces, providing adequate lighting, positioning controls near the items they control to make them easy to find, and using Arabic instead of Roman numerals. The type-face and type-spacing you use can greatly effect legibility and symbols can sometimes be used which are much more legible and understandable than fine print. Where the display is dynamic, an ability to enlarge the visual display can also be used.

In addition to making it easier to see, there are strategies which can be used to reduce the need to see things clearly in order to operate them. A judicious use of color-coding (always redundant with other cues) and following standard conventions and stereotypes can be used to reduce the need to read labels (or read labels more than the first time). In addition, all of the tactile strategies discussed under the previous guideline (I-1) can also be used here.


I-3: Operate with Color Perception Problems

Guideline: Where readily achievable, product input, control, mechanical and display functions shall be fully operable via at least one mode that does not require color perception.

Rationale: Many people have an inability to see or distinguish between certain color combinations. Others are unable to see color at all.

Goal:Anyone who has trouble perceiving color accurately can use products.

Example strategies for maximizing usability by people with color perception anomalies or color blindness:

Strategies for addressing this guideline basically revolve around eliminating the requirement that a person see color to operate the device. This does not eliminate the use of color in any way as long as the information conveyed by the color is also conveyed in some other fashion. In addition, there are a number of things that can be done to allow even individuals with color anomalies to be able to take advantage of the color-coded information. First, there are a number of common pairs of colors that are indistinguishable by people with color perception anomalies. Avoiding these color pairs avoids or reduces the problems for these individuals. In addition, as long as the colors have different hues and intensity, differently colored objects can be distinguished even on a black and white screen by their different appearance. Depending upon the product, the manufacturer may also be able to allow the user to adjust colors to match their preferences and visual abilities. It is generally a good idea to also avoid colors with a low luminance.


I-4: Locate, Identify, and Operate Controls without Hearing

Guideline: Where readily achievable, product input, control and mechanical functions shall be fully operable via at least one mode whose components are locatable, identifiable, and accurately operable without requiring the user to hear.

Rationale: Individuals who are hard of hearing or deaf cannot locate or identify those controls that require hearing.

Problem: Products that provide only audio prompts cannot be controlled by individuals who are deaf or hard of hearing. For example, a voice-based interactive system that can be controlled only by listening to menu items and then pressing buttons is not accessible. If the user has to wait for a tone in order to move to the next step in a process, an individual who is deaf or hard of hearing will have difficulty using the product.

Example strategies for dealing with this guideline:

By addressing the output issues under O-4, many accessibility problems that affect input under this guideline can be solved. For example, text versions of audio prompts could be provided (synchronized with the audio so that the timing is the same). If prompts are provided visually (O-4) and no speech or vocalization is required (I-8), most problems under I-4 will be solved.


I-5: Low Manipulation Requirement

Guideline: Where readily achievable, product input, control and mechanical functions shall be fully operable via at least one mode that does not require fine motor control or simultaneous actions.

Rationale:Individuals with tremor, cerebral palsy, paralyses, arthritis, artificial hands, and other conditions may have difficulty operating systems which require fine motor control, assume a steady hand, or require two hands or fingers for operation.

Problem: Individuals may have difficulty manipulating controls on products for any one of a number of reasons. They may have Cerebral Palsy, Parkinson's Disease, or some other neuromuscular condition which reduces the amount of physical control they may have. They may have a spinal cord injury, ALS, or MS which limits their strength or their ability to manipulate objects with their fingers. They may have arthritis which either prevents them from being able to move their joints or which results in great pain. They may have missing limbs or artificial hands which only provide a grasping function but not a twisting or other fine, manipulative motions, or their movements may just be slower, meaning that it will take them longer than average to carry out activities.

Goal: Individuals who have tremor, irregular movement, who cannot twist controls, or who can use only a mouthstick or headstick to control things will be able to operate products.

Some example strategies for creating products that are more usable by individuals with reduced manipulation abilities are provided below, grouped by topic.

Example strategies for dealing with timing and time-outs: See Guideline I-7 Non-time dependent controls.Example strategies to avoid accidental activation of controls:

Using larger buttons or controls, or buttons which are more widely spaced, is one strategy. Providing guard bars between the buttons or near the buttons so that accidental movements would hit the guard bars can help avoid accidental bumping of switches. An optional mode where buttons must be depressed for a longer period of time (SlowKeys) before they would accept input can also be used to separate between inadvertent motions or bumps and desired activation.

Avoid buttons which are activated when touched or, where that is difficult to do (e.g., with touchscreens) provide a mode where there is a confirm button which an individual can use to confirm that the item they touched is the one they are interested in. It is also a good idea to make all actions reversible and/or to request confirmation before entering into non-reversible actions.

Example strategies to deal with reduced manipulation or grip:

Latches, controls, key combinations, etc. which require simultaneous activation of two or more buttons, latches, etc. (to open, operate, etc.) can be difficult or impossible for individuals to operate who have arthritis or who operate them with a head stick or mouse stick, etc. The same goes for very small controls or controls which require rotation of the wrist or pinch and twist. One strategy would be to avoid these types of controls, another would be to provide alternate means for achieving the same functions.

Controls which have non-slip surfaces and those that can be operated with the side of the hand, elbow or pencil can be used to minimize physical activity required. In some cases, rotary controls can be used if they can be operated without grasping and twisting (e.g., a thin pie slice shape control or an edge control). Providing a concave top on buttons makes them easier to use with head sticks, mouse sticks and artificial or trembling hands.

Strategies for making it easier to insert cards or connectors include providing a bevel around the slot or connector, using cards or connectors which can be inserted in any orientation or which self-center or self-align. Locating the slot or connector on the front and near a ledge or open space that the individual can use to brace their hand or arm can also increase their ability to either rest or steady their arm/hand and facilitate use of the slot or connector.

Again, on some designs it will be controls which are difficult to manipulate which may be the most efficient, logical or effective mechanism for a majority of users. In this case, alternate strategies for achieving the same functions which do not require that fine manipulation be used could be provided.

Alternate access methods:

Where the optimal technique for users without disabilities involves techniques which would cause problems for people with physical disabilities, provide alternate means for achieving the same functions. One could also support speech input/voice recognition as an alternative input, although it should not be the only input technique (see I-8).


I-6: Operate with Limited Reach and Strength

Guideline: Where readily achievable, product input, control and mechanical functions shall be fully operable via at least one mode that is operable with limited reach or strength.

Rationale: Individuals with spinal cord injuries, ALS, arthritis, MS, MD and other conditions may have difficulty operating systems which require reach or strength.

Example strategies for minimizing reach requirements for products:

The most straight-forward strategy is to place the controls where they can be easily reached with minimal changes to body position. Many products which have controls located on different parts of the product also allow the functions to be controlled from the keyboard, which is located directly in front of the user. Allowing voice recognition to be used as an option also provides input flexibility, but it should never be the only means for achieving a function. Finally, providing a remote control option for a product not only moves all of the controls for the product together on a unit that can be positioned optimally for the individual, but also allows the individual to operate the device without having to move to it. In this case, using a standard communication format would be important to allow the use of alternate remote controls for those who cannot use the standard remote control.

Example strategies for minimizing strength requirements for products:

Basic strategies involve reducing the force needed to operate controls, latches, etc., as well as avoiding the need for sustained pressure or activity (e.g., use guards rather than increased strength requirements to avoid accidental activation of crucial switches). Other strategies involve providing arm or wrist rests or supports, providing shortcuts to reduce the number of actions needed, or completely eliminating the need to operate controls wherever possible by having automatic adjustments. Reducing the need to reach (see above) is also very helpful here.


I-7: Non-Time Dependent Controls

Guideline: Where readily achievable, product input, control and mechanical functions shall be fully operable via at least one mode that does not require a response within a period of time, or where the response time is adjustable over a wide range.

Rationale: Individuals with physical, sensory and cognitive disabilities may not be able to find, read and operate a control quickly.

Goal: Products can be operated by individuals regardless of how long it takes them to respond.

Example strategies for minimizing response time requirements:

Running out of time is a common problem for people both with and without disabilities. Addressing the problem of individuals with disabilities usually involves just applying and extending the strategies traditionally employed. The easiest solution is to avoid any time-out situations or places where the user must respond to a question or moving display in a set amount of time or at a specific time (e.g., a rotating display). Where timed responses are required or appropriate, allowing the user to adjust them or set them to very high values can be useful. Warning a user that time is running out and allowing them to secure extended time can also be used in many cases. Finally, if the standard mode of operation would be awkward or inefficient, then an alternate mode of operation could be provided which provided these abilities.


I-8: No Speech Required

Guideline: Where readily achievable, product input and control functions shall be fully operable via at least one mode that does not require speech.

Rationale: Many individuals cannot speak or speak clearly either due to physical disability or deafness. Products which require speech in order to operate them, and which do not provide an alternate way to achieve the same function will not be usable by these people.

Example strategies for avoiding speech:

Basically, the way to address this guideline is simply to provide an alternate mechanism for achieving all of the functions which are controlled by speech. If a product includes speech identification or verification, an alternate mechanism for this should be provided as well.

Example strategies to maximize use of speech systems:

It is helpful to try to maximize the number of individuals who can use their speech to control the product even if they have a disability. Almost all of the standard strategies for improving speech recognition reliability will be helpful here. In addition, it is important to include individuals who are deaf or who have dysarthria (speech movement disability) in the subject populations that are used to develop the voice recognition algorithms, so that the algorithms will better accommodate with the speech characteristics exhibited by these groups.


I-9: Language and Cognitive Requirements

Guideline: Where readily achievable, product input, control and mechanical functions shall be fully operable via at least one mode that minimizes the cognitive, memory and learning skills required of the user to operate the product.

Rationale: Many individuals have reduced cognitive abilities either from birth, accident/illness, or aging. These include reduced memory, sequencing, reading, and interpretive skills.

Goal: No one is prevented from using a telecommunication product or feature because they cannot figure out how to operate it.

Example strategies for minimizing language, memory, learning and cognitive skills required:

Most of these strategies in this category are just extensions of techniques for making products easier for everyone to learn and use. Many of these can be found in any human factors design manual, including following conventions, using standard colors and shapes, grouping things together which work together, etc. On devices which have some controls that are used by everybody and other controls which would only be used by advanced users, it is generally good practice to separate the two, putting the more advanced features behind a door or under a separate menu item, etc.

Some of the techniques and strategies listed for providing access for individuals who are blind are also very helpful here. For example, devices which read the contents of the display aloud, controls which will announce their settings or their functions, etc., not only make it possible for people who are blind to figure out the controls and displays, but also make it easier for these products to be used by individuals who have difficulty reading.

Wherever possible, designing products that are self-adjusting helps to eliminate additional controls which must be learned, and reduces the visual clutter. On systems which have sign-in procedures, it is helpful to allow users' settings to be associated with them when they sign in, insert their identification card, etc. The system can then autoconfigure to them. Some new "smart cards" are being designed with user preferences encoded on the card.

Where a complex series of steps is required, some type of cueing might be provided to help lead the person through the process. It is also helpful to provide an "undo" or back up function, so that any mistakes can be easily corrected. Where systems are not reversible, some type of confirmation might be requested.

On labels and instructions, it is helpful to use short and simple phrases or sentences. Abbreviations should be avoided wherever possible. Eliminating the need to respond within a certain time or to read text within a certain time window is also helpful here.


5.3.2 Output, Displays and Feedback


O-1: Visual Information Available in Auditory Form

Guideline: Where readily achievable, all information (text, static or dynamic images and labels) which is provided visually shall also be available in auditory form.

Rationale: Some individuals have difficulty seeing or reading, or cannot see or read.

Problem: Individuals with cognitive or language disabilities, as well as individuals with low vision or blindness, are not able to access text which is presented visually, but not available in auditory form.

In addition, people with low vision or blindness are also unable to access information presented graphically or in other visual forms unless it is also presented auditorally. Visual presentations which are purely decorative in nature are not as essential as that information which is needed for understanding and use of the products.

Goal: All information is perceivable by all individuals who cannot read or see.

Example strategies for achieving this objective:

The most universal way to address this problem is to provide speech output of all text which is presented on the display as well as labels of the product. For information which is presented in non-text form (e.g., a picture or graphic), a verbal description should also be provided, unless it is just decorative in nature. Although most people who are legally blind do not know braille, it is an extremely effective mechanism for those who do: providing braille labels for controls, for example. Large raised print can also be used but is generally restricted to rather large objects due to the size of the letters.

When speech output is provided, there could be a mechanism to allow for the spoken message to be repeated if the message is very long. A message for stepping through them is helpful.


O-2: Make Visual Information Accessible by People with Low Vision without Requiring Audio

Guideline: Where readily achievable, all information which is provided through a visual display including text and dynamic images, labels or incidental operating cues shall be perceivable via at least one mode by individuals who have low vision but are not blind, without requiring audio presentation.

Rationale: Individuals with severe visual disabilities often also have severe hearing disabilities (especially older users) and cannot rely on audio access modes used by those who are blind.

Goal: All people who have low vision but are not legally blind can use their vision to access visually presented information on a product.

Example strategies for achieving this goal:

Strategies for achieving this guideline generally revolve around providing larger, higher contrast print and graphics. Individuals with 20/200 vision can see lettering if they get close to it, unless it is very small or very poor contrast. Although 14 or 18 point type is recommended, it is usually not possible to put this size print on small devices. Making the lettering as large and high contrast as possible, however, will maximize the number of people who are able to use the product. On displays where the font size could be varied, allowing the user to increase the font size is helpful, even if it means that the user must pan or step around the display in order to see the full display.


O-3: Perceive Moving Text

Guideline: Where readily achievable, text which is presented in a moving fashion will also be available via at least one mode in a static presentation mode at the option of the user.

Rationale: Moving text can be an access problem because individuals with low vision, physical or sensorimotor disabilities find it difficult or impossible to track moving text with their eyes.

Example strategies for achieving this guideline:

Strategies here usually involve some mechanism for freezing the text. A "Times Square" display which provides a line at a time would be one example. Allowing the user to freeze the text to read it would be another strategy. A third approach might be simply to provide the same information in another type of display which does not move.


O-4: Visual and/or Tactile Availability of Auditory Information

Guideline: Where readily achievable, all information which is provided auditorially, including those incidental operating sounds and speech, which are important for use of the product, shall be available via at least one mode in appropriate visual form and/or where appropriate in tactile form.

Rationale: Individuals who have difficulty hearing or who are unable to hear the product are unable to hear auditory output or to hear mechanical and other sounds that are emitted by a device which may be needed for its safe or effective operation

Goal: Information which is presented auditorally is available to all users, even if they cannot hear.

Example strategies for achieving this guideline are provided below by topic.

Alerting and status functions:

To alert the user to a call, page, or other message, or to warn the user, a visual or tactile signal that will attract the person's attention can be used. In portable devices, a tactile signal such as vibration is often more effective than a visual signal for this purpose because a visual signal may easily be missed. A remote vibrating signaler is a promising solution if it is not readily achievable or effective to build vibration into a portable device. For stationary devices, a prominent visual indication in the field of vision (e.g., a screen flash for a computer user, a flashing light for a phone user) is effective.

Text presentation:

To inform the user of the status of a process (e.g., line status on a phone call, power on, saving to disk, disconnected), text messages may be used. It is also desirable to have an image or light that is activated whenever acoustic energy is present on a telephone line.

Speech messages can be made accessible if portrayed simultaneously in text form (as standard or optional mode) and displayed where easily seen by the user. Such captions should usually be verbatim and displayed long enough to be easily read. If the equipment provides speech messages and the user must respond to those messages (e.g., interactive voice response and voice mail), a text-telephone-accessible method of accessing the system could be provided. If the system provides interactive communication using speech and video, it would be helpful to provide a method and channel for allowing non-speech communication (e.g., text conversation) in parallel with the video.

Certain operations of equipment make sounds that give status information, although these sounds are not programmed signals. Examples include the whir of an operating disk drive and the click of a key being pushed. Where sounds of this type provide information important for operating the device, they should be made visually accessible by use of a light or other visual confirmation of activation.

Voice interaction:

If equipment uses voice or speech messages to which the user must respond (e.g., voice mail, interactive voice response, etc.), a TTY-accessible method for using the system could also be provided. If the system provides interactive communication using speech and video, a mechanism for allowing non-speech communication in parallel with the video could be provided.


O-5: Make Auditory Information Accessible by People Who are Hard of Hearing without Requiring Vision

Guideline: Where readily achievable, all information which is provided auditorially, including incidental operating sounds, which is important for use of the product, shall be available via at least one mode in enhanced auditory fashion (for example, increased amplification, or reduction of background noise).

Rationale: Individuals who have difficulty hearing but are not deaf find it much easier to use their hearing than to have to rely on access strategies used by people who are deaf.

Goal: All people who are hard of hearing but not deaf can use their hearing to access auditorally presented information on a product.

CLOSELY RELATED GUIDELINES: See also C-2 and C-3 which deal with hearing aid compatibility.

Example strategies for addressing this guideline:

Strategies for addressing this guideline include improving the signal to noise ratio by making the volume adjustable, increasing the maximum undistorted volume, and minimizing background noise by such methods as better coupling between the signal source and the user.

Alerting tones are most likely to be heard if they involve multiple tones separated in frequency which contrast with the environment. Occasionally, varying tones may be preferred for attracting attention.

If speech is used, it is best to test its intelligibility with individuals who are hard of hearing to maximize its clarity and ease of understanding to this population group. Again, the ability for the user to have any messages repeated or to repeat the message if no response is received from the user is helpful. For essential auditory information, the information might be repeated and an acknowledgment from the user requested.

The intelligibility of the output can also be maximized by the location of the speakers and by keeping them away from noise sources. However, visual displays are often more desirable than loud prompts or alerts, because the latter reduce privacy and can annoy others unless the amplified signal is isolated by means of a headphone, induction coupling, direct plug-in to a hearing aid, or other methods. (See strategies under O-4.) The use of a telephone handset or earcup which can be held up to the ear can improve intelligibility without disturbing others in the area. If a handset or ear cup is used, making it compatible with a hearing aid (T-coil) allows the user to directly couple the auditory signal to their hearing aids. If the microphone in the handset is not being used, turning it off will also reduce the amount of background noise which the person hears in the earpiece. Providing a headphone jack also allows individuals to plug in headphones, induction loops, or amplifiers which they may use to hear better.


O-6: Prevention of Visually-Induced Seizures

Guideline: Where readily achievable, visual displays shall be designed so as to avoid high probability of triggering a seizure in an individual with photo-sensitive epilepsy.

Rationale: Individuals with photo-sensitive epilepsy can have a seizure triggered by displays which flicker or flash, particularly if the flash has a high intensity and is within certain frequency ranges.

Examples of strategies for achieving this guideline:

Strategies here will revolve around reducing or eliminating screen flicker or image flashing. In particular, the 10-30 hertz range is the most sensitive frequency range, and should be avoided. The chance of triggering seizures can also be reduced by avoiding very bright flashes which occupy a large part of the visual field (particularly in the center of the visual field) in order to minimize the impact on the visual cortex.


O-7: Prevention of Sound-Induced Seizures

Guideline: Where readily achievable, sound displays shall be designed so as to avoid audio behaviors that create a high probability of a seizure in an individual with sound-induced epilepsy.

Rationale: Individuals with sound-induced epilepsy can have a seizure triggered by audio output.

Examples of strategies for achieving this guideline:

Strategies here revolve around avoiding sudden or rapidly repeating and loud sounds.


O-8: Audio Cutoff

Guideline: Where readily achievable, products which use audio output access modes, shall have a headphone jack or personal listening device (e.g., phone-like handset or earcup) which cuts off the speaker when used.

Rationale: Individuals using the audio access mode, as well as those using a device with the volume turned up, need a way to limit the range of audio broadcasts.

Example strategies for achieving this guideline:

If an audio headphone jack is provided, a cut-off switch can be included in the jack so that insertion of the jack would cut off the speaker. If a telephone-like handset is used, the external speakers can be turned off when the handset is removed from the cradle.


5.3.3. Documentation


D-1: Ability to Access Product Documentation and Related On-Line Information

Guideline: Documentation (printed, on-line or tutorial, including promotional materials) shall be accessible to and usable by individuals with all disabilities or alternate formats shall be available.

Rationale: People who have disabilities often are unable to use standard printed documentation if they cannot see, documentation that is presented on screen in small fonts if they have poor vision, documentation that presents important information auditorially if they are deaf, etc.

Example strategies for achieving this guideline:

Strategies for addressing this guideline fall into two categories. Making the standard documentation as accessible as possible and providing alternate formats.

There are a number of strategies for making print easier to read. These include using larger type size, high contrast between lettering and background, and not printing text over patterned backgrounds. Materials that can be copied in black and white are easier for users to enlarge using copier machines. Controlling the language level and keeping the document as easy to read as possible is also important.

Manuals which are spiral bound or bound so that they can lie flat are easier for people with physical disabilities to use. Tabs are also helpful.

Electronic manuals and on-line help have the advantage that they can be easily presented in either visual or auditory form (via speech synthesizer), and can also be more easily electronically enlarged. In order for this to work however, all information must be available in electronic text form. Any information that is presented in graphic form would also need to be presented in the text or the graphics would have to be described. Any text which is presented as a graphic and cannot be saved as ASCII or is not written to the screen using the standard system text drawing tools would not be accessible to the screen reader/voice synthesizer.

Alternate forms for print documentation include braille, audio tape, and enlarged printed documentation (14 to 18 point). Videotapes can be captioned (either open or closed captioned) to make them accessible by those who are hard of hearing or deaf. Adding video description can make many of them accessible to people who have low vision or blindness. The most universal form of alternate documentation is the ASCII text file. However, it is only usable by those who have a computer which may or may not fit the consumer profile for a product.


5.3.4. Compatibility Guidelines


C-1: External Electronic Access to All Information and Control Mechanisms

Guideline:Where readily achievable:

  1. All information needed for the operation of a product (including output, alerts, labels, on-line help, and documentation) shall be available in a standard electronic text format on a cross-industry standard port;
  2. All input to and control of a product shall allow for real time operation via electronic text input into a cross-industry standard external port and in cross-industry standard format; and
  3. The port used for 1 and 2 shall not require manipulation of a connector by the user.

Rationale: Some individuals with severe or multiple disabilities are unable to use the built-in displays and control mechanisms on a product.

Example strategies for achieving this guideline:

The two most common forms of manipulation-free connections are an infrared connection or an RF connection point. At the present time, the IrDA infrared connection point is the most universally used approach.

At the present time, a cross-industry standard for alternative control and display does not exist. A standard protocol is under development. A cross-industry standards effort is required in order to provide a common reference point that both CPE and SCPE manufacturers can work toward.


C-2: Connection Point for External Audio Processing Devices

Guideline: Where readily achievable, products providing auditory output shall provide the auditory signal via an industry standard connector and signal level.

Rationale: Individuals using amplifiers, audio couplers, and other audio processing devices need a place to tap into the audio generated by the product in a standard way.

Problem: Individuals who cannot hear well can often use the products if they can isolate and enhance the audio output. For example, they could plug in a headphone which makes the audio louder and helps shut out background noise; they might feed the signal through an amplifier to make it louder, or through filters or frequency shifters to make it better fit their audio profile. If they are wearing a hearing aid, they may directly connect their hearing aid to the audio signal or plug in a small audio loop which allows them to couple the audio signal through their hearing aid's built-in T-coil. Devices which can process the information and provide visual and/or tactile output are also possible.

Example strategies for achieving this guideline:

The most common strategy for achieving this objective is the use of a standard miniature plug-in jack. For small products, a subminiature phone jack could be used.

This is an area where on-going coordination between manufacturers of CPE and manufacturers of assistive technology would be important, to ensure that changes in technology are addressed by standards.


C-3: Hearing Aid Coupling

Guideline: Where readily achievable, products providing auditory output via an audio transducer which is normally held up to the ear shall provide a means for effective wireless coupling to hearing aids.

Rationale: Individuals who are hard of hearing use hearing aids with a T-coil feature to allow them to listen to audio output of products without picking up background noise and to avoid problems with feedback, signal attenuation or degradation.

Example strategies for achieving this guideline:

The Hearing Aid Compatibility (HAC) Act defines a telephone as hearing aid compatible if it provides internal means for effective use with hearing aids that are designed to be compatible with telephones which meet established technical standards for hearing aid compatibility.

The technical standards for the HAC telephones are specified in two documents, ANSI/EIA-504-1989, "Magnetic Field Intensity Criteria for Telephone Compatibility with Hearing Aids," and ANSI/TIA/EIA-504-1-1994, "An Addendum to EIA-504," which adds the HAC requirements.

A good strategy for addressing this guideline for any product held up to the ear would be to meet these same technical requirements.

If not readily achievable to provide built-in telecoil compatibility, an accessory or other means of providing the electro-magnetic signal is the next strategy to be considered. Alternate methods of internal coupling, not yet identified, are also encouraged, and these should be developed in concert with the hearing aid industry and individuals who are hard of hearing.


C-4: Non-Interference with Hearing Technologies

Guideline: Where readily achievable, products shall not cause interference with hearing technologies (including hearing aids, cochlear implants, and assistive listening devices) which are used by a product user or bystanders.

Rationale: Individuals who are hard of hearing use hearing aids and other assistive listening devices, but they cannot be used if products introduce noise into the listening aids because of stray electromagnetic interference.

Example strategies for achieving this guideline:

Strategies for reducing interference (as well as improving hearing aid immunity) are being researched. The most desirable strategy is to avoid the root causes of interference when telecommunications equipment is initially designed. The industry should work toward transmission and channel-sharing technologies that do not generate interference, and should test new technologies for possible interference with assistive technologies.

If the root sources of interference cannot readily be removed, then shielding, placement of components to avoid hearing aid interference, and field-canceling techniques are among those that may be effective.

The ongoing work of ANSI C-63, which is working toward improvements in usability of certain phones by wearers of hearing aids, should be monitored and incorporated if a standard is adopted.


C-5: Prosthetic Compatibility of Controls

Guideline: Where readily achievable, touchscreen and touch-operated controls shall be able to be activated without requiring body contact or close body proximity.

Rationale: Individuals who have artificial hands or use headsticks or mouthsticks to operate products have difficulty with capacitive or heat-operated controls which require contact with a person's body rather than a tool.

Problem: Individuals who wear prosthetics are unable to operate some types of products because they either require motions that cannot easily be made with a prosthetic hand, or because products are designed which require touch of the human skin to operate them (e.g., capacitive touchscreen kiosks), making it impossible for individuals with artificial arms or hands to operate the kiosks, except perhaps with their nose or chin. Some individuals who do not have the use of their arms use either a headstick or a mouthstick to operate products.

Example strategies for achieving this guideline:

Avoid controls and mechanisms which require a grasping and twisting motion. Use controls and sensors which can be activated with a mechanical device.


C-6: Text Telephone Connectability

Guideline: Where readily achievable, products which provide a function allowing voice communication and which do not themselves provide a text telephone functionality shall provide a standard non-acoustic connection point for text telephones. It shall also be possible for the user to easily turn any acoustic pickup on the product on and off to allow the user who can talk to intermix speech (live microphone) with text telephone use.

Rationale: Individuals who use TTYs to communicate using text over telephones must have some non-acoustic way to connect TTYs to telephones to get clear TTY connections. Acoustic coupling is subject to interference from ambient noise, as many handsets do not provide an adequate seal with TTYs. Therefore, alternate (non-acoustic) connections are needed. Control of the microphone is needed for situations such as pay-phone usage, where ambient noise picked up by the mouthpiece often garbles the signal (user needs to be able to mute the handset microphone). Some users of TTYs cannot hear and use the TTY to receive communication but can talk and use speech for outgoing communication. The microphone on/off switch on the telephone should therefore be easy to flip back and forth or have a push-to-talk mode available.

Goal: A text telephone can be connected to and used with any telecommunications product supporting speech communication without requiring purchase of a special adapter, and the user is able to intermix speech and clear text telephone communication.

Example strategies for implementing this guideline:

The most common approach today is to provide an RJ-11 jack. On very small products, where there may not be room for this large jack, a miniature or subminiature phone-jack wired as a "headset" jack (with both speaker and microphone connections) could be used as an alternate approach. In either case, a mechanism for turning the phone mouthpiece (microphone) on and off would reduce garbling in noisy environments, while allowing the user to speak into the microphone when desired (to conduct conversations with mixed voice and text telephone).

Note: For equipment that combines voice communications, screens, keyboards and data communication functions, it is desirable to build in text telephone capability for direct access to voice communications channels.


C-7: Text Telephone Signal Compatibility

Guideline: Where readily achievable, products providing voice communication functionality shall be able to support use of all cross-manufacturer non-proprietary standard signals used by telecommunication devices designed for use by or with people who are deaf, hard of hearing or have speech impairments.

Rationale: Some telecommunication systems, which have been developed and released, compress the audio signal in such a manner that standard signals used by text telephones are distorted or attenuated, preventing successful text telephone communication over the systems.

Goal: A text telephone can be used with any product providing voice communication function.

Example solution strategies for achieving this guideline:

The de facto standard of domestic text telephones is Baudot, which has been defined in ITU Recommendation V.18. This guideline can be addressed by ensuring that the tones used can travel through the phones compression circuits undistorted. It is even more desirable to provide undistorted connectivity to the telephone line in the frequency range of 390 Hz to 2300 Hz (ITU-T Recommendation V.18), as this range covers all of the text telephone protocols known throughout the world.

An alternate strategy might be to recognize the tones, transmit them as codes, and resynthesize them at the far end.

In addition, as noted above, it should be possible for individuals using TTYs to conduct conversations with mixed voice and TTY, and to control all aspects of the product/system and receive any messages generated by the product/system.