Judy Dixon
Part 1 of this article will discuss the history of braille codes in the United States with particular emphasis on how braille became usable with computers. This encompasses both braille as it is sent from a computer for embossing, and braille as it is read from a computer with a refreshable braille display. How did the braille codes change to make these things possible?
Part 2 will look at how braille is used with screen readers on computers and mobile devices. What braille codes are available to access the contents of a computer screen? How do these codes make it possible for a braille reader to pursue different tasks?
Introduction
To be a useful tool for reading and writing, braille must be able to represent, to the extent possible and practical, the array of printed material that a blind person needs to pursue education, employment, hobbies, and all the other activities of everyday life. With only six dots in a braille cell, representing the more than ten thousand print characters found in today's world has become a real challenge.
The codes used to display this vast array of characters must be comprehensive, and able to represent printed material accurately and completely. But the code must also be straightforward and understandable by the blind person using it. It would be a simple matter to devise a code representing thousands of characters but making that code easy to learn and memorable is definitely not a simple matter.
Technology has helped by increasing the number of dots available, but it has also significantly increased the complexity of material to be represented. Nevertheless, today, braille users are reading literature, science, math, music, knitting patterns, computer programs, and much more all in braille.
This article presents a brief history of the braille codes in the United States and discusses how they are used by screen readers on computers and mobile devices to provide braille readers the greatest possible access to the vast world of print.
Early Braille Codes in the U.S.
For a couple of centuries, blind people only read braille that was embossed on paper. Every braille character had no more than six dots. There were only a few different braille codes, used to represent different languages. For the most part, there was one braille code per language.
Slowly, over time, the braille codes used throughout the world evolved. In the United States, contracted (grade 2) braille, much as we know it today, was adopted in 1932. A simpler form of braille, grade 1-1/2, was commonly used until the middle of the 20th century. This grade of braille had about 50 contractions. With the publication of English Braille, American Edition in 1959, contracted (also then called grade 2) braille became the accepted code. This grade of braille had 189 contractions, and virtually all literary braille reading material published in the United States was produced in this code for the next 57 years.
ASCII Braille
In the 1960s, a braille code for sending text from a computer to a braille embosser was developed. This code was based on ASCII, the American Standard Code for Information Interchange which was originally published as a computer standard in 1963. This braille code is referred to as North American ASCII braille, but also as the MIT Braille Code because MIT had a hand in its development to go with their braille translator Dotsys and their embosser, Braille Mboss.
Initially, the 64 possible dot combinations of braille were mapped to the 95 printable ASCII characters. The 26 letters and the 10 digits were assigned to their ASCII counterparts; other characters such as plus and minus were assigned the dots that were then in use; while, still others, such as left and right parentheses, were assigned logical, mirror image combinations. Many others received random assignments.
Later in the 1960s, the ASCII code was extended to be an eight-bit code which meant that there were 256 possible characters. Despite the expansion of the printed computer character set, the braille code, a six-dot code, remained at 64 characters until the early 1970s, when braille embossers capable of using an eight-dot braille code became available from Triformation Systems, Inc. These embossers were based in part on the Braille Mboss developed at MIT. They added dots 7 and 8 to the bottom of the braille cell, and were capable of embossing braille from computers using eight-bit ASCII.
In the United States, there is wide agreement on the mapping of braille characters to the lower 128 characters of ASCII but there is no accepted standard for which braille character stands for what character in the extended ASCII character set from 128 to 255.
Refreshable Braille Displays
Refreshable braille displays made their first appearance in the late 1970s. The very early devices, The Elinfa Digicassette and the Telesensory VersaBraille had six-dot braille cells. These were stand-alone devices with limited note-taking and document-reading capabilities.
But soon, as the general public began regularly using computers, the idea of using a braille display to access the contents of a computer screen caught on. Six-dot braille cells were not capable of accurately showing the text on a computer screen without braille translation software in the act. If translated into contracted braille, the one-for-one relationship between the characters on the screen and the braille cells would be lost. The solution was to create braille displays with eight-dot cells. Eight-dot cells quickly became the norm and continue to be in use today.
Dots 7 and 8, together or separately, were used to provide information about the character being displayed that could not otherwise be shown with the normal six dots. For example, it is a fairly common practice to use dot 7 on a refreshable braille display to show that a letter is capitalized, and to use dots 7 and 8 to indicate that the character is in a certain type form, such as bold, highlighting, etc. Most screen readers use dots 7 and 8 together to indicate the presence of the cursor.
The Computer Braille Code (CBC)
The fact that computers and braille embossers were using an eight-bit code but braille books were still printed in a six-dot code was not a problem for computer programmers who were the primary users of computer-related information in the 1970s and early 1980s.
However, in the late 1980s, things began to change. Books and magazines for the general public began to contain what had been thought of as computer-related material-filenames, websites, email addresses, and so forth. Blind people who used braille displays could read web addresses and filenames easily but there was no good way to show such material on paper. The literary braille code of the day was not up to the challenge.
The Braille Authority of North America (BANA) decided that what was needed was a Computer Braille Code. The purpose of this code was to represent, in six-dot braille, on paper, the computer-related text that had become common in everyday literature.
The 26 letters of the alphabet would be the same in the computer braille code as in literary braille, but the characters would stand only for the letters themselves. The letters would be used to spell words. No contractions would be used. Every letter, number, and punctuation mark would have its own separate meaning so that there would be no ambiguity, precisely as was done in ASCII.
Because there are only 64 possible dot combinations in a six-dot braille cell and there were 95 printable characters in ASCII, some characters had to be assigned a two-cell sequence. This was accomplished by using a prefix of dots 4-5-6, which appeared as the first cell in all of the computer braille code's two-cell symbols. Dots 4-5-6 indicated to the reader that the next cell was something different from what it would have been without the prefix. If it was a letter of the alphabet, that meant it was uppercase. If it was dots 4-5, then it was a tilde and not a caret. If it was a second dots 4-5-6, then it was an underscore character. The same dot prefix was used to create indicators to go into and out of the Computer Braille Code so that it would be clear to the reader exactly what braille code was being read.
In November 1986, BANA approved the Code for Computer Braille Notation for publication, and it was officially adopted in 1987. According to BANA, the goal was to "make the Code for Computer Braille Notation a realistic code, capable of unambiguous representation of current computer notation but flexible enough to respond to changing and demanding needs." (Braille Authority of North America 1987).
During the 1970s and 1980s, braille codes to represent music, math, and science continued their development. They too have evolved over time but a detailed look at these codes is beyond the scope of this article.
Unified English Braille (UEB)
In 1991, Dr. Tim Cranmer, Chair of the committee that had developed the Computer Braille Code and Dr. Abraham Nemeth, originator of the Nemeth Code for Mathematics and Science Notation wrote to BANA to raise a red flag over the state of the braille code. The literary, math, and computer codes all had different characters to show some of the same symbols. The alphabet, of course, was the same, but after that, things diverged rather quickly.
What was needed was to unify the braille code. BANA began working on code unification for the literary, math, and computer codes, all except music. Soon, BANA realized that unifying English Braille was not just a United States concern. BANA reached out to other English-speaking countries and in 1993, the International Council on English Braille (ICEB) was formed. Over the next decade, work continued on developing and evaluating a unified English braille code. The overarching goal for this code was unambiguity which was accomplished in all but a few minor ways.
In 2004, ICEB decided that Unified English Braille was sufficiently complete to be released as a viable and usable code for literary, math, and computer materials. In 2012, UEB was adopted as the code of the land by BANA with an implementation date set for 2016. All of the ICEB member countries are now using UEB.
With the adoption of UEB, the Computer Braille Code was no longer needed so it was declared obsolete by BANA. Because of its familiarity to many readers, the Nemeth Code for Mathematics and Science Notation continues to be an official braille code in the United States.
The North American ASCII Braille Code that was developed so long ago continues to be used with refreshable braille displays, and for sending braille from computers to embossers. Users who want to read a one-for-one representation of text on a computer screen can opt to use this code, usually referred to as Computer Braille. This term, however, should not be confused with the Computer Braille Code which had been created to represent computer-related material on paper, and is no longer in use.
