Afkpuz, for the script, it's set up to support operation in LMCE. $3 is the third argument when the script is run.
To run it by hand, run
20_Olevia2XX_5XXT_TV.sh 1 1 /dev/ttyS0
replacing /devttyS0 with your serial port.
If you still can't get it to work, I can post a windows executable that I wrote to test the interface.