The CM11A X10 controller (or its various incarnations, such as the CM12CH model for Switzerland), made by X10 Pro, is one of the most ubiquitous (and cheapest) X10 controllers available. If you want to write a program that will talk to this interface you will definitely need to know not only its communication protocol but also its serial line settings (baud rate, parity and so on).
Googling for this information wasn’t easy, so here is my humble contribution to the pagerank of the page that gives this invaluable information: