This part of ISO 13400 specifies the vehicle communication interface and test equipment requirements for a physical and data link layer based on IEEE 802.3 100BaseTx. This interface serves as the physical basis for IP-based communication between the vehicle and test equipment. This part of ISO 13400 specifies the following aspects: — requirements for signal and wiring schematics in order to ensure physical layer compatibility of the vehicle interface and Ethernet networks and test equipment communication interfaces; — activation and deactivation of the diagnostic Ethernet interface; — mechanical and electrical diagnostic connector requirements.