William F. Crandall, Jr., Ph.D.


Source Material on
for people who have a print reading impairment

The Smith-Kettlewell Eye Research Institute
Rehabilitation Engineering Research Center
2318 Fillmore Street
San Francisco, CA. 94115


For further information:
Bill Crandall, Ph.D. Scientist
Bill Gerrey, Electronics Engineer
John Brabyn, Ph.D. Dir. RERC




Effective mobility depends upon proper orientation; for mainstream society this is accomplished by printed signs. People who are print disabled, are blind, or have other visual impairments are at a disadvantage for the lack of labels and signs. For sighted travelers, signs provide identification and directions. In the broadest sense, signs comprise a menu of choices for travelers; they confront them with the options available at any given point in their travels. Signs act as a form of memory for travelers; signs "remind" travelers about important characteristics of the environment.

Currently, persons with
severe visual impairments most often require extensive assistance from strangers in order to travel in unfamiliar areas. In the best case, the information they receive is accurate, concise, and in the appropriate language. Such an ideal source of information is seldom available. In urban areas, persons who are blind may have safety concerns about approaching strangers for assistance. Finally, blind people just do not like to be dependent upon others for information -- especially if there are suitable alternatives.

Safe and independent travel
for blind and visually impaired persons is made especially difficult by lack of access to the signs and landmarks the rest of the population takes for granted. Braille signs, even where available, do not replace the functions of print signage because they cannot be read from a distance; they have to be searched for and found before the information they contain can be used; and a majority of people who are unable to read print signs (because of visual limitations) have not learned to read Braille. And it is reasonable to assume that older persons-- the fastest growing population of people who are blind-- would be especially unlikely to learn Braille when the onset of visual loss occurs later in life.

Remote Infrared Audible Signage:

Remote infrared audible signs, or RIAS, allow people who are print disabled to directly know not only what, but where. Just as non-disabled people visually scan the environment to acquire both label and direction information, remote infrared signs directly orient disabled people to the labeled goal and constantly update them as to their progress to that goal. That is, unlike Braille, raised letters, or voice signs which passively label some location or give instructions to some goal, the remote signage technology developed at The Smith-Kettlewell Eye Research Institute (Talking Signs®) provides a repeating, directionally selective voice message which originates at the sign and is transmitted by infrared light to a hand-held receiver some distance away. The directional selectivity is a characteristic of the infrared message beam; the intensity and clarity of the message increases as the sign is "pointed at" or approached. This ensures that the people using the Talking Signs® system can choose to get feedback about their relative location to the goal as they move towards it. Talking Signs® are light and small, easy to install, consume very low power, and are easy to program with human voice or synthesized voice messages. Talking Signs® remote infrared audible signage system (RIAS) conforms to the ADA guidelines which stipulate that an accommodation must also be "refusable" [Title V, sec. 501(d) ADA].