Every time 'Open port' in the MU2-ESP is clicked, 'Framing error' is displayed.
This message is displayed when the bit rate of the COM port of the connected PC and that of the MU-4 is different. If the initialize terminal has a button, turn on the power while pressing this button. The initialized bit rate of the MU-4 is 19,200bps. Set the PC bit rate to 19,200bps with the MU2-ESP, and try again.
If you are already using a circuit board, and the bit rate of the MU-4 is fixed, set the bit rate for any of 2,400, 4,800, 9,600, 19,200, 38,400, or 57,600bps, and try again.