Datasheet in PDF form for the Texas Instruments SN74S1053, a Schottky-family bus-termination diode array, here with the NS suffix that TI uses for its SOP package variant. At only 12.8 KB the document is probably a short summary or ordering sheet rather than the full datasheet. Use it to confirm the pinout and clamp behaviour when a data line on an old logic board is being pulled down or shows a short. Compare the package marking on the chip with the code in the file before you swap a part.
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.