Efficient implementation of voice channels over CAN networks

The Controller Area Network is widely used as fieldbus in many distributed control systems. In addition to control information, a voice communication running on the same bus may have several advantages. This paper deals with an efficient implementation of a voice channel over an already designed CAN network. In particular, the solutions to minimize the band occupation and to cope with the large variability of the time taken to transmit a CAN message are described. A proof-of-concept demonstrator, consisting of two CAN stations provided with audio capabilities, has been realized and tested in an existing distributed control system designed and installed in a high-end motorcycle. Finally, in order to fully demonstrate the feasibility and effectiveness of our approach, the system performance under several bus load conditions has been characterized.