This paper mainly studies the data communication protocols of control area network (CAN) for the vehicle information systems. The objective is to create the environment of the line replaceable unit (LRU) in these systems. The data transmitted from CANBus are one of the valuable resources. There are 8 bytes of them in each transmission. If they are appropriately planned, the data communcation protocol can improve the efficiency of the communication, e.g., arbitrations, masks, filters of nodes for CAN can be assigned arbitrarily on line. Even the software of CAN unit can be upgraded and downloaded on line, too. Upon the above concept, this paper will propose a feasible configuration of the vehicle information systems as well as a kind of possible data communication protocols.