How to employ the FONTALT system variable and the ACAD.FMP file
Basic AutoCAD stuff we might need to know about AutoCAD automatic font replacement.
Left unsaid are the serious issues with Special Characters and Unicode support in font definitions.
The NCS and the ISO employ the Windows Arial True Type font for a number of reasons. The special characters are included and the full depth of Unicode characters is supported.
Both the NCS (National Cad Standard) and ISO (Internation Standards Organization) are explicit about the fonts you should use.
This is about readability - readability at various plotted scales and with multiple applications on varied hardware and software.
The issue other critical issue being that in the font mapping exchange text might not come over with the correct characters.
To better understand Special Character issues see Our Special Friends have Character
That post includes a list of special characters in Unicode and how to get them.
The NCS and ISO Standards specific font issues are covered in In Font of the Face of Horror post.