VoiceOver iOS: Braille Code Explained for Refreshable Braille Displays

Note: VoiceOver iOS my substitution for The VoiceOver Screen Reader on the iPad, iPad 2, iPhone, or iPod.
Provided your student has an iPad, iPod, or iPhone connected to a Refreshable Braille Display (which is basically a Braille Keyboard with a Touch Screen) Braille reading and writing are accessible while using the VoiceOver Screen Reader.

VoiceOver: Braille Codes

The iPad, iPod, and iPhone all have a built in Screen Reader called VoiceOver. The VoiceOver utility allows the user to set what type of Braille is displayed on their Refreshable Braille display for both Braille reading and Braille input. VoiceOver iOS displays contracted, un-contracted, 6-Dot, and 8-Dot Braille.
What is un-contracted Braille?

Un-contracted Braille Code is also referred to as Literary Grade 1 Braille. Un-contracted Braille consists of the symbols for: letters, punctuation marks, numerals, and composition signs. It simply means spelling it all out.
What is contracted Braille? Contracted Braille is also referred to as Literary or Grade 2 Braille. Contracted Braille is basically a lot like short hand. For example, instead of writing out each individual letter in the word (and), a contraction is used to represent all 3 letters. The theory behind contracted Braille its suppose to save time and space. Contracted Braille is the most common form of Braille. If a book is ordered for a student in Braille, it is in contracted Braille, unless it's math, then its Nemeth. This is tough for beginning readers as Grade Two English Braille (America Edition) has 250 symbols for: letters, punctuation marks, composition signs, numerals, contractions, single-cell words, and short-form words.

What is ASCII ?
Braille ASCII is a subset of the ASCII character set which uses 64 (i.e. @, #, _! =) of the printable ASCII characters to represent all possible dot combinations in six-dot Braille. ASCII letters are the same as un-contracted Braille. Numbers correspond to Nemeth number without a number sign. Braille contractions for punctuation are different than Literary Braille.

What is 6-dot Braille?
6-dot Braille is used for Literary or ASCII/computer Braille Code.

What is 8-dot Braille?
8-dot Braille is referred to by several names to include, ASCII, computer Braille, and Linear Braille to name a few. An 8-dot cell Braille cell increases the number of dots from six to eight. Instead of the 64 possible dot combinations in a six-dot cell, an eight-dot cell yields 255 possible dot combinations. Typically, the dots of the eight-dot braille cell are numbered 1, 2, 3, 7 downward on the left and 4, 5, 6, 8 downward on the right.
In an effort to make braille and print more directly equivalent without the need for any intermediate processing, a set of fonts called Dotsplus was developed. Dotsplus includes six- and eight-dot fonts. The six-dot font presents text similar to traditional uncontracted braille. The eight-dot font presents most two-cell characters of the six-dot font as single cells. For example, in the eight-dot font, uppercase letters, which in six-dot braille are shown with the letter in one cell preceded by a dot six in a cell by itself, are shown as the letter with an added dot seven in the bottom left corner of the eight-dot cell.

Yet another form of 8-dot Braille emerging is LAMBDA. LAMBDA is an acronym for Linear Access to Mathematics for Braille Device and Audio Synthesis. This is an emerging Braille code for Refreshable Braille Display users.
The Braille Authority of North America, (BANA) recognizes that eight-dot braille systems have proven to be extremely useful, particularly in the technical areas such as mathematics and the sciences. While BANA currently has no official codes that incorporate eight dots, BANA plans to closely monitor all developments in the area of code extensions involving additional dots and will continue to assess their utility through its technical committees.

What Kind of Computer Braille does VoiceOver iOS Use?
From what I have observed VoiceOver probably uses both 6-Dot and 8- Dot Dotplus.
Both 6-dot and 8-dot are used to input numbers and other keyboard symbols. It appears the difference the difference between the 6-dot and 8 - dot Braille is the Computer Braille indicator. 6-dot Braille utilizes dots (4,5,6), while 8-dot Braille utilizes dot (7) located under the contraction. While inputting Braille using 8- dot Braille, dot (7) key is also used. For example: @ dots (7,4). The dot 7 key functions much like the shift key. To capitalize a letter such as, A, press dot (1) then tap dot (7). To capitalize a letter using a capital sign dot (6), turn 8-dot Braille off.

And Finally VoiceOver iOS appears to use some 8-dot Braille LAMBDA Braille aka Braille for Refreshable Braille Displays. This form of Braille is typically used to display information within the status cell.

What a Status Cell?
VoiceOver uses the far left or right cell of your Braille display information about buttons, sliders, text fields, pop menus, announcements, low battery, text font/style, and cursor location. This extra Braille cell is called the Status Cell. It's basically heads up about open pop up menu, changes in the text styles, and other announcements. I.E. "You've Got Mail"
(link to status cells)

VoiceOver underlines the VoiceOver cursor using Braille dots 7 and 8 to help you locate the VoiceOver cursor within the line of Braille. Similarly, when you are editing or selecting text, the text selection is represented by dots 7 and 8.

VoiceOver also indicates the position of the text selection cursor, called the “I-beam,” by flashing dot 8 of the Braille cell preceding the text selection cursor and dot 7 of the Braille cell trailing the text selection cursor.
VoiceOver Status Cell Meanings Link (embed web link to status cell page)

So What Setting Do I Want? That depends on what your trying to read or write.

To read or type text such as word processing utilize 6- dot contracted or un-contracted Braille. You'll know 8-dot Braille on if punctuation marks are displayed in ASCII.
Literary Grade 2 Contracted Braille: - VoiceOver, - Braille, - Contracted Braille On, - 8- dot Braille off.
Literary Grade 1 Un-Contracted Braille: - VoiceOver, - Braille, - Contracted Braille Off, - 8-dot Braille Off
Math or Science: you must use ASCII Code not Nemeth. - VoiceOver, - Braille, - Contracted Braille off, - 8-dot Braille On.

Nemeth Code: does not recognize Nemeth Code

Lastly, the iOS devices have more VoiceOver functions than listed in the manual. I found information on Apple's website pertaining to VoiceOver in the manual for using Lion iOS.