Brother HL-1050 Technical Reference Manual page 12

User units
Vector graphics
Vertical plot size
VMI
Coordinate units specified by the user with the HP-GL and HP-GL/2 SC
command.
A method of defining graphic images in terms of coordinates, points and lines.
The HP-GL and HP-GL/2 graphics languages use this method.
The original vertical size of an imported HP-GL and HP-GL/2 image.
Vertical motion index. The vertical distance that the print position moves down
the page when a line feed is performed. This can be set using printer commands or
with the printer's control panel by adjusting the "Lines" menu option in PAGE
FORMAT MODE.
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