AiM systems acquire data from the ECU of your vehicle.
The list of available ECU drivers, constantly updated and upgraded, includes 1,000 + different ECUs, either Stock and Racing; they are sorted by manufacturer/vehicle model: for each ECU you find the proprietary communication protocols, including the standard OBDII ones.
From a hardware point of view, AiM systems manage the following data lines: CAN, RS232 and K-Line.