This is a spreadsheet from Samsung showing the RS-232 commands for TVs capable of RS-232 communication, covering model years 2006 through 2011. If a command is not listed in this file, it doesn't exist!
This is a spreadsheet from Samsung containing the HEX values that correspond to the NECx2 infrared code list that Jasonvp posted. If a command is not listed in this file, it doesn't exist!