Keystroke: b from Page Codes menu.
This command causes DBT to put codes before and after any text you have highlighted, so that the text will not get split across a page break.
If no text is highlighted when you select this command, the codes will be placed before and after the cursor; any text that you type will be kept on a single page, until you type the right arrow key to step beyond the second code.
For example, to keep a company's address all on one page, you would highlight the address and apply block protect. Or position the cursor first, apply block protect, type the address, and then hit the right arrow key.
Of course, if the highlighted text is too long to fit on one braille page, the command cannot be honored.