During communication, a phenomenon like the attached waveform occurred.
The potential of Sx was floating and something like a pulse waveform was observed in Rx/Tx.
The circuit is as shown on p17 of the datasheet, with Sx and Sy directly connected to the MUC.
The resistor R2 is 2.2kΩ and the capacitor C2 is connected to 47pF.
Can you think of any reason why this would happen?