RAR archive for the ASUS EM1900I-E, identified only by model name, with no note on whether it carries a schematic, boardview or BIOS image. Its size of 260 KB suggests a compact document or a small firmware set rather than a full service package. Extract it with any RAR-capable tool and inspect the file types inside. Before relying on the material, make sure the model and revision printed on the board match, and if a BIOS is included, read and keep the original flash content before reprogramming the chip.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @boardview. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.