I do not understand the voltage monitor. In my opinion pin 10, black, is always GND. Also there are other pins wich cannot get another function. So, can you guys explain.
No, that's not the case. At the PC side I leave the setting at 115200 baud. A few months ago it worked fine but since I loaded firmware version 4.1 the problem came up. So, I loaded the latest version 5.5 but the problem persists.