Literature-coded PDF of roughly 617 KB; the name gives only a Texas Instruments document number, not the part it describes. The SDLS series normally holds TI logic datasheets, so a 74-series TTL device is likely, though this needs to be checked on the first page. Such documents provide function tables, pin configuration, electrical characteristics and switching waveforms. After identifying the covered chip, a technician can use it for pin lookup and level checks; always match it to the IC printed marking.
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.