Manual of digital electronics written in Spanish, a general reference rather than a schematic for any particular equipment. The name gives no device, brand or board number. Manuals of this kind explain logic families, gates, flip-flops, counters and how digital signals are measured with a multimeter, logic probe or oscilloscope. The 545 KB PDF opens in any PDF viewer. Treat it as theory to support fault-finding on boards, then rely on the actual service schematic for pin numbers and part values.
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 @canalesquematicos. 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.