PDF of around 835 KB carrying only a document code in its name, so the exact device is not stated. The SDLS prefix is used for Texas Instruments logic datasheets, which suggests a 74-series TTL family part, though that should be confirmed by reading the title page. Larger files in this series often include detailed switching characteristics, function tables and package drawings. Use it for pin assignment and electrical limits once the covered part number has been matched to the chip on the board.
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.