Road vehicles. Implementation of World-Wide Harmonized On-Board Diagnostics (WWH-OBD) communication requirements. Connection between vehicle and test equipment|Information exchange, Network layer (OSI), Open systems interconnection, Data transfer, Road vehicle engineering, Communication equipment, Road vehicles, Diagnostic testing, Data link layer (OSI), Vehicle components, Transport layer (OSI), Diagnostic programs, Physical layer (OSI), Session layer (OSI), Data transmission, Road vehicle components, Electronic equipment and components