I just bought an arduino and want to use it to control my X10-system, at the end it is the idea to put on an ethernet shield and control my X10 modules via an app on my TAB/mobile.
Your code was very usefull to test my setup. I have some problems however. I'm using the CM11a (belgian version of your CM12u I suppose)
I have my arduino connected to a MAX232 to convert the TTL into RS232. (followed this diagram http://avrprogrammers.com/doc-max232-arduino.php
But I'm not sure about the pin-out of the CM11 module. There is a lot of contradictionary info on the net about this pinning. How did you connect your CM12 to the arduino?
The furthest I got was to request the 'power supply' but there the answer was allways 'power down'.
Thank you! Dax