Character LCD module datasheet for PC2004LRU-DSC-H, a larger 970 KB PDF that probably includes more detailed drawings or controller data. The part code indicates a 20 character by 4 line display, with DSC-H selecting a particular option combination and revision H. Use it to read the pin functions, controller instructions, timing, power and contrast requirements and mounting dimensions when servicing equipment. It is also handy when comparing against the MEA variant. Make sure the code on the module matches this exact suffix before relying on it.
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 @acodis_lcd_datasheets_EDID. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.