Well unfortunately the manufacturer has been less than forthcoming with technical specs, due to (at least partially I'm sure) the fact that they offer a similar interface as what I'm trying to build, but that "upgrade" is over $200 for the unit itself and then ongoing service fees to keep it working. Hence my desire to build my own on the cheap.
Is there any way I could hook up the brain itself to some sort of serial port monitor to capture the communication?