Compact 128 KB PDF datasheet carrying only the code SDLS209. Because the name lacks a part number, the component covered is unknown until the document is opened; the code follows the pattern of Texas Instruments logic literature. A technician would read it for pin assignments, the function table and electrical limits when testing a logic chip in circuit or choosing a replacement. Check that the logic family letters and package outline on the board agree with what the sheet lists.
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 @datasheet_technar_org. 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.