PDF datasheet covering the PC2004LRS-CEA-B LCD module, a 20x4 character display going by the usual 2004 convention. The LRS and CEA-B parts of the code distinguish build options such as backlight type and mounting, so a near-identical number may not behave the same. Inside you would normally find the connector pinout, absolute maximum ratings, contrast and backlight drive data, and a mechanical drawing. Repair work centres on checking supply pins, the contrast node and backlight current against these figures.
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.
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The standard format for schematics, block diagrams, power-sequence charts and service manuals.