Samsung SM-A11 schematic section showing the SIM card reader circuit, saved as a 4.33 MB PDF. It details the SIM tray connector, the card supply, clock, reset and data lines, plus the protection and filter parts along the way. Handy when the phone reports no SIM or drops the card intermittently: you can measure the SIM voltage, check for shorted protection diodes and trace detect lines. Opens with any PDF reader; make sure the board revision of the handset you are fixing matches the drawing.
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 @phoneSchematics. 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.