This International Standard provides the specifications of: . common AVI/AEI transaction requirements, which define the common steps of any AVI/AEI transaction; . AVI/AEI application interface to standardized wireless protocols (referred to as the "Air Interface") supporting the AVI transaction requirements, so as to enable interoperability. In Figure 1 the conceptual architecture model is shown for AVI transactions between "On-board Equipment" and "Fixed Equipment". The air interface concerns the reference point DELTA in ISO 14814.