Just an aside- you probably ought to put out a call for pinouts of the cable that connect the Phatbox to various head units as well. Given the variety of HU interfaces and the fact that the guys at Phatnoise were probably making at least some effort to make the Phatbox as universal as possible, it would be good to know where on the Phatbox (and more to the point, on the 8051) connections were expected to occur for standard UART vs. differential UART vs. CAN bus, etc.
-c