I´ve used the terminal example from QT Creator (https://doc.qt.io/qt-5/qtserialport-terminal-example.html) in order to communicate with a attached device via usb to rs232 dongle.

My settings are 460800 Baud 8 data bits 1 stop bit no flow or parity.

I`ve probed the RX and TX lines with a oscilloscope and each character is send out to the device and resent via TX back to PC but the readyRead signal isn`t emitted.

The example is working with QT 12.5.1 but not with 5.13.1 with MinGW 7.3.0 64bit on the same machine.