VT100: Up arrow or Down     VT200: Up arrow or Down arrow
    arrow
    DEFINE_KEY Function: UP, UP_NOWRAP, DOWN, or DOWN_NOWRAP

    Moves the cursor vertically on your screen without altering
    the data you have already entered. Note the following about the
    cursor behavior:

    o  If the cursor is at the top of the screen when you press the
       Up arrow, the cursor appears in the same column at the bottom
       of the screen.

    o  If the cursor is at the bottom of the screen when you press
       the Down arrow, the cursor appears in the same column at the
       top of the screen

       If the screen display you receive is larger than 24 rows
       deep, you can use the Up arrow and the Down arrow keys to
       move through the display. These keys scroll the screen display
       up or down.

       If you want the cursor to wrap to the opposite edge of
       the display, use the key sequence EXT + Up arrow or
       EXT + Down arrow.