During my investigation, I inadvertently overwrote the serial port configuration for the connected devices. So I am now working to get it all back. I have attached screenshots of the config settings that brought back communication that is not garbled. There is no physical connection to port 6, which I guess was initially used for the UPS serial communication but not anymore. Also, ports 9 and 10 are connected to Hornet and SuperBee, both of which have not been communicating for a while and are to be replaced, so there is no way to confirm communication with them. Otherwise, the remaining devices seem to be communicating as before.

I still could not establish communication with the XGS-600 controller using the serial port settings given in the manual, which also happen to work via Serial to USB adapter, so I will revisit the problem later. My immediate plan is to do a Serial Ethernet, then Ethernet to Serial, and then Serial to USB connection to see if the USB code still works. If it does then at least I know the problem is not coming from the Serial to Ethernet adapters. Then I guess I will replace the controller with my laptop and see what signal comes through when I send a message to the controller via the IOLAN serial device server. Hopefully, I can discover what's wrong by this point.

Note to self: Before doing anything, do a sanity check by comparing the settings on the IOLAN SDS and the config settings that worked for the Serial to USB communication and post an elog for this for reference.