Thanks for the response! I have three RS485 ports with A, B, and GND terminals.
RS485 ports image
Please correct me if I’m wrong, but to perform a loopback test, I should connect the A and B terminals of two RS485 ports and then send test data between them, right?
I’m not entirely sure about the hardware flow control, but according to the kernel module source code, the DTR signal is used. Unfortunately, I only have remote SSH access to the device, so I cannot inspect the timings with an oscilloscope.