From my recollection, the B984-100 acted very similar to the way a Modicon 984 PLC acted, except for it's limited instruction set, and limited memory and I/O. The I/O is 800 Series I believe. I think the communications is Modbus like the other old 984's. Hope this helps. If you want to contact me seperately, I can see if one of my support technicians could track down further info for you. [email protected]