The "intelligence" of the board relies on the communication bus architecture:
Safety, compliance, and ESD notes
The availability of schematics for the GS44B, GS54B, and NM-C561 can vary. Official manufacturer websites, technical forums, and dedicated electronics databases are good sources. The quality of schematics also varies; high-quality schematics are clear, detailed, and accurate, while lower-quality ones may be hard to read or contain errors.
Before the EC (Embedded Controller) wakes up, the board needs 3V_ALW (Always On) and 5V_ALW .