Chapter 10. Using Braille Displays

If you have a supported braille display connected to (or in the case of a Bluetooth display, paired with) your computer, VoiceOver automatically detects it and sends it information about what is displayed on the screen. You can connect multiple braille displays to your computer and each display will mirror the same content at the same time, which can be useful in a classroom setting.

By default, VoiceOver displays uncontracted braille. You can set a preference to use contracted braille, in which case VoiceOver dynamically changes the display under the cursor from contracted to uncontracted braille, so that you can read and edit more easily, and then changes back to contracted braille when you move the cursor.

A braille display typically contains more than just the contents of the VoiceOver cursor. It describes the contents of the entire line on which the VoiceOver cursor is focused, including items to the left and right of the VoiceOver cursor. For example, when the VoiceOver cursor is focused on an item in a window, the braille device displays items like icons, checkboxes, and pop-up menus, as well as text that is to the left and right of the item in the VoiceOver cursor. This collection of items—the VoiceOver cursor and the items to its left and right on the same horizontal line—make up a “line” of braille.

When you interact with an item in the VoiceOver cursor to get more detail about it, the braille description changes to provide more detail as well. For example, if you move the VoiceOver cursor onto a toolbar, VoiceOver describes only the toolbar on the braille display, because toolbars stretch the entire width of a window. When you interact with the toolbar, the braille display describes each item in the toolbar from left to right.

VoiceOver raises dots 7 and 8 to indicate the position of the VoiceOver cursor, to help you locate it within the line of braille. (You can turn off this feature in VoiceOver Utility). Similarly, when you’re 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 provides additional information about what’s on the screen using three status cells. Each status cell provides a designated type of information. You can set preferences for the number of status cells you want to use and their location on the braille display. For example, you can choose to use the cell that shows text status and set its location to be on the left of your display.

VoiceOver detects the type of braille display connected to your computer and sets default preferences appropriate for your display. Use VoiceOver Utility to assign VoiceOver commands to keys on your braille display. You can use the braille display while listening to VoiceOver speak, or you can mute the speech. If your braille display has a Perkins-style keyboard, you can type on it.

Before you can use a supported Bluetooth braille display with VoiceOver, you must pair your braille display. You can pair only one Bluetooth braille display at a time. You pair the display only once; it remains paired until you remove it from the pairing. After your braille display is paired, VoiceOver detects it whenever it’s turned on and within range; if it’s your primary braille display, you can then use it.

Sometimes a line of braille is too wide to fit on the braille display. You can “pan” the line by pressing the left and right buttons on the display to move through the line. Each left or right pan moves according to the number of cells (including status cells) your display contains.

When you move the VoiceOver cursor using the VoiceOver keys, the braille display automatically pans when necessary to follow it, even wrapping to the previous or next line.

Many braille displays have router keys above the braille cells that you can use to move the cursor. Generally, you press the router key above a particular item in the line of braille to move the VoiceOver cursor or selection to that item.

Pressing a router key over a control moves the VoiceOver cursor to that control if the VoiceOver cursor is not already there. If the VoiceOver cursor is already on that control, pressing the router key performs the control’s default action. For example, to click a button, you could press the router key to move the VoiceOver cursor to the button and then press the router key again to click the button. You would not have to touch the computer’s keyboard at all. Similarly, when you’re reading or navigating text and you press a router key, the VoiceOver cursor moves to that location in text.

You can also press the router key above a status cell to display an expanded braille description of each dot in the cell. To exit the description, press any other router key.

The content of the line on the screen where the VoiceOver cursor is focused appears in the cells of the braille display. VoiceOver uses status cells to provide additional information about the line, such as the text attributes.

If your braille display has dedicated status cells, VoiceOver uses those cells to show the additional information, based on the preferences you set in VoiceOver Utility. Otherwise, VoiceOver uses the first one to three cells on the left or right of the display, based on your preferences. VoiceOver reserves another cell, which it leaves blank, as a separator between the status cells and the other cells.

VoiceOver sends announcements about events that are not represented visually on the screen to the braille display. For example, if an application running in the background needs attention or if a new window appears onscreen, VoiceOver sends an announcement to the braille display.

VoiceOver stores up to 30 announcements in the history; the most recent announcement is the first one. If you set a preference to use the status cell that shows general display status, you can review announcements.

VoiceOver detects whether your braille display provides input keys and assigns common VoiceOver commands to the keys. In this way, it helps you work more efficiently by using the computer keyboard less. For example, VoiceOver might assign the Down command to the D3 key; when you press that key on your braille display, the VoiceOver cursor moves down one line on the screen. You can change the default assignments and add your own.

Mac OS X supports a wide range of USB and Bluetooth braille displays.

Note:The table indicates displays that are Bluetooth only, or are USB and Bluetooth. If neither label appears, the display is USB only.