Hi Guys,
Years i am working with integration and SAP CAR / POSDM – POS DTA. I summary major integration landscape and data flow for SAP CAR POS DTA.
I try to simply data flow landscape help you image picture of data from start to end.

(1) Legacy systems: In retail industrial now, consumer can buy goods from channels those called “Touch point”. Customer can buy from store, e-commerce website, phone call, mobile apps, etc.. sales data stored into local database server or cloud base. Sales transaction data will be translate in to SAP CAR format such as EDI standard.
Legacy system can transfer data to SAP PO (Process Orchestration) via multi protocol, example: via file system (FTP/ SFTP) via webservice technology (SOAP, REst…).
(2) Integration Middle-ware system. Here SAP PO is SAP’s integration system help transfer data from source system to SAP system effective. SAP PO connect to SAP CAR via RFC (Remote Function Call) protocol.
(3) IDOC Workbench, data from SAP PO will send to SAP CAR and put into “Inbound queue”. Data in queue will be process and pass to CAR workbench as sequence. In IDOC workbench, technical or integration consultant can monitor inbound message, solve technical issue and re-process.
(4) Inbound Queue, SAP CAR inbound queue help record data in temporary dataset, CAR consultant can process queue data, delete queue data per partner system. Inbound queue help business define data sequence when posting to ERP.
(5) SAP CAR Workbench, this procedure help CAR consultant monitor sales transaction. After define business rules, Data validation and posting, Workbench help process data step by step. All issues during validation and audit happened will display in workbench, operator can know exactly what issue is.
(6) Validation, Validation procedure help validate master data of sales transactions.
(7) Data audit, this is one of major procedure of POS DTA. Data audit help check logic of data.
(8) Raw data transfer, for reporting purpose raw data will send to SAP BW. In some business requirement, financial transaction single posting also requested.
(9) Aggregation, sales transaction and payment transaction will be aggregated by standard condition or customizing conditions.
(10) Transfer, SAP CAR connect to SAP S/4 HANA via RFC protocol and send aggregated sales / payments transactions to S/4 HANA.
(11) SAP S/4 HANA / SAP BW receive data from SAP CAR
Thanks,
Cuong Dang