We like to keep the WaveShare USB to serial adapter in our circuits for easy reconfiguration of the attached Xbees3. I am getting a TX signal via the 3.3 V Max 3483 Transceiver (RS485 to Serial).
If I monitor the plain signal, it has a strength of >3 V. If the TX line touches the WaveShare board, the TX signal drops to 1.5 V, which will not be recognized by the XBee3. The drop occurs with or without Xbee connected.
I was able to confirm the problem being on the side of the WaveShare board by trying with a different USB to serial adapter. And it worked. Unfortunately, we have the WaveShare boards stockpiled...
Any suggestions? I'm quite newbie, so please forgive if I've overlooked something obvious.