Good you have save Params...that looks like the Baud rate maybe set wrong between cnc to PC try 4800 or 9600........also there were alot of cheap USB to RS232 converters sold that had bad chipsets in them and they just did not work. Get a name brand like Tripplite or there are other Options like RS232 to IP converter wireless or wired to network the cnc. Lets us know how things go.

DJ