A FON1 font, or console font, contains a set of 256 grayscaled, monospaced characters. It begins with a header of this form:
|0x0000||4*1||Identifier||The characters 'F', 'O', 'N', and '1'.|
|0x0004||2||Width||Unsigned value for character width.|
|0x0006||2||Height||Unsigned value for character height.|
|0x0008||*||Data||RLE-compressed data for all characters in sequence.|
The data create a Width × (Height × 256) grayscale image in which the glyphs are in sequence from top to bottom. The darkest color, 0x00, is transparent.
ZDoom provides a FON1 font in a file named confont.lmp in zdoom.pk3. This is used for the console font.