问题
Issues with Android-2-Arduino communication made it clear to me I have no clue which parts of the chain are (directly) affected by the baud rate. Could you please confirm/correct following assumptions?
The 'baud rate' value is not related to anything on the Android side. Therefore it is not a bug when an Android USB/Serial library only sends the baud rate value (9600, 125000, etc.) to the other side via controlTransfer, not storing it anywhere, not setting it somehow to the Android device itself.
When calling usbConn.controlTransfer with 'baud rate' parameter on Android, this command is NOT redundant to me calling Serial.init(baudRate) in the Arduino code. Both these calls are intended for different HW/parts. Both of those parts reside on Arduino. (Both, obviously, must be called with identical value.)
来源：https://stackoverflow.com/questions/43679630/where-does-baud-rate-value-go-in-serial-android-2-arduino-communication-over-u