Limits for Displaying the Grid Lines

The top of each line and the left of each row on the screen are the limits for displaying the grid lines on the screen.

The host system always sends the grid-line designation data, which specifies any one of the four types of the grid lines (a), (b), (c), (d) (no grid line), for the 1920 (24 lines by 80 columns) positions respectively.

As a result, a grid line, such as (e) is displayed by gathering these vertical lines and horizontal lines.

Figure 1. Grid Line Types

The limits for displaying the grid lines are as follows:

Figure 2. Grid-Line Display Limits

1. A horizontal grid line can be drawn between any character-displaying position within the limits of (a), (b), (f), (e).

   The horizontal line above the 25th row, (c)–(g), is always displayed by the system.

2. A vertical grid line can be drawn between any character-displaying position within the limits of (a), (c), (h), (d).

   The vertical grid line (e)–(g) cannot be drawn on the right.

3. The grid-line screen format cannot be updated partially.
4. Note that the grid lines are removed when displaying the characters from the first column to the fourth column.