This part of ISO 11519 specifies general definitions for low-speed serial data communication up to 125 kbit/s for road vehicle applications. Its object is to define the general architecture of the communication network and the content of the — data link layer and — physical layer for transmission between the different types of electronic modules on board road vehicles. NOTE 1 Parts 2, 3 and 4 of ISO 11519 are entirely independent and should be regarded as self-contained entities. No attempt should be made to implement any combination of the specifications in these parts