AES participants exchange data through Electronic Data Interchange (EDI). If you use SAP GTS to access the AES, the system generates an intermediate document (IDoc) for each export declaration. This IDoc is a document with an SAP-specific format that can be used to exchange data between various SAP systems and between SAP systems and third-party systems. The IDoc is converted into an XML message by a converter and sent electronically to the customs authorities. If the customs authorities system issues a response message, the converter "translates" this message into IDoc format for inbound processing in SAP GTS.
The UCC also provides a simplified declaration without formal authorization. Customs authorizes this simplification on a case-by-case basis by acceptance of the customs declaration. The exporter will be required to submit the missing information in a supplementary export declaration within a specific time-limit.
Simplified declarations without formal authorization are predominantly used for cross-border chain transactions. In chain transactions of this kind, one EU company commissions another company in the same Member State to deliver goods to a consignee in a third country. The delivering company does not generally have all the information and documents required and therefore submits a simplified export declaration.