It is important to appreciate how tab stops work, as they can be an important part of laying out a braille document correctly. When positioning tab stops ("tabs") in a document, it is important to set them as you want them to appear in the braille.
In a word processor program, the position of a tab stop might be indicated by a measurement in inches or centimeters, but DBT sets tab stops by column position. In braille, each column position is one braille cell.
If you do not define your own tab stops, DBT sets default tabs at 2 column intervals. Thus, if you are at the beginning of a line with your cursor in column 1, pressing the Tab key moves you to column 3. Press it again, and you move to column 5. Then to 7, 9, etc.
For any given document, you can clear DBT's default tabs and set your own tabs at specific columns. The custom tabs you set remain set until the end of the document or until you reset them. As you define each custom tab, you assign it a number (1 to 9). You can then use a DBT code to "Go to the Nth Tab".
Even if you have no tabs set, DBT provides a code you can use to tab to an absolute column position.
There are four types of tabs according to how they align your text: left, right, "decimal", and centering alignment. (Please, note that DBT provides a way to set the designated character to use for the decimal point according to language and regional expectations. See "Decimal Tabs".)
Working by example, if a tab of each alignment type is set at column position 20, their effects will be as follows.
- Left: The first character of the word appears in column 20.
- Right: The last character of the word appears in column 20.
- Decimal: As this alignment normally applies to numbers containing a decimal point, the decimal point of the number appears in column 20.
- Centering: The middle character of the word appears in column 20.
Again, in braille tabs stops are measured in cells on the page. If we tab to cell 20, then a left tab would begin in cell 20, a right tab would end in cell 20, and the decimal point would be in cell 20.