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Commercial Technology For The Blind

Editor's Note: The following article is reprinted from the June, 1996 edition of "The Braille Monitor", the publication of the National Federation of the Blind in the United States. Access to information means access to far more than books in a library. These common sense guidelines for making commercial technology usable by blind people point out one of the subtle, but extremely serious, information access problems we face. From the Editor Emeritus: As Monitor readers know, Curtis Chong is the President of the National Federation of the Blind in Computer Science. He is employed as a designer consultant by American Express Financial Advisors of Minneapolis. As a member of the World Blind Union's Committee on Technology, he recently prepared a paper concerning guidelines for designing modern technology that can be used by the blind. Very few subjects have more importance to the blind than this one, and Mr. Chong's straightforward approach is refreshingly understandable.


Although there will always be a need for some specialized technology designed especially for the blind (for example, the Braille writer), it is preferable for people who are blind to be able to operate the same technology that is commercially available to the general population. The problem we face is that, more often than not, commercially developed technology is designed in such a way as to preclude efficient and convenient use without sight. It is not that manufacturers deliberately set out to prevent blind people from using the technology they develop. It is simply that they haven't considered the possibility that a blind person might want to use their product. Moreover, even if some developers wish to ensure that blind people can use a specific device, they face the problem that there are no easily obtainable guidelines which they can follow to meet this goal.

In other words, their design efforts are likely to be conducted on a hit-or-miss basis. The ideal goal is to have electronic appliances usable by everyone, including people with physical, sensory, or cognitive disabilities. However, in attempting to achieve this goal, it is important to recognize that features that make the appliance usable for one disability group may cause the device to be unusable for another.

For example, replacing printed labels with raised pictographic symbols may be beneficial to people with learning disabilities, but they are useless to blind people who may read Braille or raised print. Accordingly, it should be clearly understood that this paper focuses specifically upon the access requirements of persons who are blind. This paper will attempt to establish broad principles and suggest some specific practices that may be followed by developers of commercial technology so as to ensure that the products they develop can be operated by a blind person without sighted assistance. It should be viewed as a guide that can be used to stimulate thinking on the subject -- not as the definitive solution to the problem. This paper will not address the problem of access to computers and the graphical user interface. Many organizations have devoted substantial time and energy to this problem. However, relatively little thought and effort have been devoted to the question of how modern consumer electronics can be designed so as to be operated by those of us who happen to be blind.

As a growing number of these devices use digital controls and computer technology to carry out basic functions, our ability to use them steadily diminishes.

Guiding Principles

Before making specific design recommendations, I would like to suggest a few principles that should be used to shape the design effort. These include operability, integration, usability built-in, and accessible documentation.

Operability in this context means that a specific appliance is designed in such a way that a blind person can exercise all of its essential functions without sighted assistance. A good example of this concept is the television. We may not be able to see the picture while enjoying our favorite movie, but we are able to turn the television on and off, adjust the volume, and select the desired channel without asking a sighted friend to help us. (At least, this is the case with most televisions available today.)

The principle of integration is aimed at ensuring that features necessary to operate an appliance without sight are an integral part of the design and benefit everyone who uses the appliance -- not only the blind.

A telephone with buttons that can be operated by touch is an excellent example of this concept. The fact that the buttons can be felt is beneficial not only to the blind user but also to everyone else. Other examples include the talking clocks and calculators formerly manufactured by Sharp and the talking answering machines currently available from such companies as AT&T and Panasonic. With regard to these latter devices, the speech generated is sufficient to enable full control and operation without sighted assistance.

Usability built-in means that ideally a peripheral (and often expensive) piece of assistive technology is not necessary for a blind person to operate an appliance. Although in some cases necessity may force us to use assistive technology (e.g., a Braille 'n Speak equipped with an infrared transmitter) to operate some equipment with infrared or other connection schemes installed, this is not the preferred method of controlling an electronic appliance. It makes no sense for us to have to use a piece of equipment costing a thousand dollars simply to operate an appliance that may at most cost a few hundred. One method for accomplishing this goal would be to provide speech output, either built into the appliance or available as a low-cost accessory. Given the increasing sophistication of digital technology, this may well become a necessity for the appliances of tomorrow.

Accessible documentation refers to the concept of making instruction manuals available in a medium other than print. For manuals prepared using a word processor, it should be possible to make ASCII-text versions available (for a nominal fee) so that the manual could be transcribed into Braille or read on the blind person's own computer.

Guidelines for Physical Controls and Labels

Physical controls usually take the form of knobs, dials, switches, slide controls, and buttons. In digitally controlled devices, they have sometimes taken the form of switches activated by light, pressure, heat, or capacitance. Usually these switches are located on smooth control panels that are totally unusable by the blind. Moreover, these switches often provide only visual cues to indicate that they have been activated. In some cases remote controls with tactile buttons are available, but the user is presented with only visual cues to indicate what the appliance is doing.

Physical controls should not depend upon sight alone for operation. Consideration needs to be given to the use of other senses (e.g., touch and hearing) to manipulate controls. This would be of benefit to all users, blind and sighted alike. Sighted users will appreciate not having to divide their visual attention between two activities and will also enjoy the ability to operate the appliance -- even when lighting is poor. Blind users will appreciate the ability to operate what would otherwise be an unusable appliance. Here are some suggested guidelines. Bear in mind that other approaches are possible if sufficient creativity and motivation are brought to the design effort.

  1. Push buttons should be discernible by touch. The button can be indented, raised, or contained within a raised boundary that can clearly be detected by touch.

  2. Push buttons should never be touch-activated. Some minimal pressure should be required to activate the control, and the appliance should provide tactual or audio feedback to indicate when the button has been pressed.

  3. The shape of a push button can provide important clues to its function. Consider using texture or other tactually detectable changes (such as a raised symbol) to identify buttons for unusual or important functions.

  4. Small, closely clustered controls are often difficult to negotiate by touch. Consider spacing controls so that each one can be detected easily by touch. Ideally, spacing between controls should be no less than one-half the control's width or height. Crowding controls together to provide what appears to be a seamless surface makes them difficult to operate by touch.

  5. Buttons that turn modes on or off should provide tactile or other nonvisual means to indicate the on or off state. These might include: Leaving the button in when a mode is on and causing it to pop out when the mode is off, or generating a high tone when the mode is turned on and a low tone when the mode is turned off.

  6. Slide controls can be made more useful if they have notches, clicks, or tactile markings indicating normal settings.

  7. The use of a continuous rotary selector (as in a radio tuning knob) will be enhanced for everyone if a notch, dot, or raised pointer is placed on the knob. Also it is very helpful if the selector has a detent for every possible setting so that individual settings can be selected by touch.

  8. Tactile labels should be built in to supplement visual labels which the blind cannot use. These may consist of raised sans serif upper-case characters made of thin lines. Tactile labels should not use pictograms or other non-textual symbols. This assumes that the controls being labeled are not dynamic in nature -- that is, that the controls always perform the same function.

  9. Braille labels and overlays should be made available upon request.

Guidelines for More Sophisticated Digital Devices

Appliances which use digital technology pose a more complex problem for blind people. Individual buttons do not perform the same function consistently. Modes change automatically, without notice. Often, the operator is required to select an item from a menu displayed visually. Although for some devices a remote control with tactile controls may be available, the blind person may be unable to perform any control or selection functions because the choices to be made are displayed visually with no verbal prompts.

In other words, many appliances have today become dedicated computers, with all that the term implies. Although many digital devices with relatively simple control systems can be operated without sight, it is often necessary for the blind person to spend considerable time and effort memorizing numerous sequential procedures. The control of these devices is made more difficult when they memorize settings -- even when turned off. Sometimes these devices will shift from one menu to another after a predetermined amount of inactivity time has passed, making it difficult for the blind operator to determine what function is being selected.

The guidelines presented here are at best a preliminary attempt to deal with the digital appliances of today. It should be understood that, as digital appliances become even more sophisticated, these guidelines will need to be adapted. Here are some suggestions that can enable blind people to operate digital appliances independently with the maximum possible efficiency.

  1. There should be a way for the user to return the appliance to a state where all mode settings are known. This is different from the "Reset" function that many appliances have to restore factory settings. The intent here is to enable the operator to predict what will happen when specific procedures are executed. If the operator makes a mistake in executing the procedure, he or she should be able to return to a known starting point to try again. In addition, the operator should be able to perform any desired function from this known state with a minimum number of keystrokes.

  2. If the design calls for displayed menus to change automatically after a certain amount of inactive time, there should be a way to lock the display so that it doesn't change, or, failing that, an audible cue should be provided to alert the operator to the fact that the display has changed. In this latter instance the design should be such that the user can predict what the display will change to, without having to see it; and it should be possible to turn off the audible cue when it is not needed.

  3. The design of the digital appliance must be such that a blind operator can memorize a sequence of events that can be executed consistently to perform a specific function or set a desired state.

If for any reason the sequence of events needs to be aborted due to an error in execution, the appliance should provide some means of letting the blind operator know that the error has occurred and return the device to a known state. A simple beep will suffice for most situations. Other audible cues should be provided to indicate, for example, when data are to be entered (as in the security code for an automatic teller machine); when an automatic sequence is beginning and ending; and when the appliance will no longer accept input. Audible cues may not always be desired; therefore, there must be a method for turning them off.

  1. If speech output is built in to the appliance or provided as a low-cost accessory:

A. There should be a way to turn the speech on and off. This mechanism should not require sight for use. People who do not need the speech may find it a novelty at first but will quickly find it an annoyance if they cannot disable it.

B. Speech should be responsive and interruptable. This means that it can be stopped and started almost instantly, simply by pressing a key which causes new speech to be generated.

C. A button should be provided which causes the speech to speak the entire display, if it is one line, or the entire list of menu choices, if the display consists of multiple lines. If a choice is to be selected from a list, a method should be provided to speak each choice individually so that the operator will know what is being selected.

D. Speech output does not need to carry more information than the visual display unless it is essential to the operation of the appliance.

E. A headphone jack should be provided for private listening. This will enable the blind person to hear confidential information as in the case of an automatic teller machine.


The principles and guidelines set forth in this paper should not be viewed as the total answer to the question of how technology can be made usable by people who are blind. For one thing we cannot possibly know all of the forms that future technology will take and the problems that such technology will pose for the blind. Moreover, technology is changing at an accelerating rate. Solutions that may work for today's technology will certainly not solve the problems that will arise with the technology of the future. We can hope, however, that designers, engineers, and marketers will make a conscious effort to ensure that the products emerging from their work can be used by those of us who are blind. If they will consider that technology will be used by everyone -- blind and sighted alike -- and plan their work accordingly, we stand a better chance of maintaining parity with our sighted peers in our ability to use electronic appliances.