Funny - I always assumed that the triangles in the electrical circuits in the diagrams represented diodes. According to 'late' they do not?
Hey look! EEng who claims to be an ex Boeing engineer agrees
By the way, the post #25 diagram does not make the source switching for DC Standby and Battery Bus clear. Treat the arrows feeding the buses as diodes (although that may not be the actual implementation). Current does not flow through the battery bus from the TR unit to back feed the hot battery bus.