... keyboard :F1 key; 4, ok→mouse :left key; 5, return→mouse:right key; 6, Note→keyboard: Ctrl + P key; 7, PageUp→keyboard: PageUp key; 8, PageDown→ keyboard corresponding PageDown key ... after without keys pressed , LED is off, and in this state,you can press any key,LED works. 4, charging: when ... the power lower 3.3 V,LED flicker. ·B· other ...