Not quite true....it also decides where and whether to send that data...for instance on some cars if the seat belts are not engaged it wont send the signal to release the electronic handbrake...and lots of other similar linked actions. It also changes the signal to and from a CAN bus data signal to a CAN bus controller signal. Receiving: it converts the data stream from CANbus levels to levels that the CAN controller uses. Transmitting: it converts the data stream from the CAN controller to CANbus levels. So if you are expecting you mic data to pass through the canbus unchanged (if it even goes through it....I have my doubts) I dont think it will be. Unlike you two Im most certainly only a keen amateur....so I happy to be proven wrong!!!!