After the CRM Server has been supplied with initial data following the data transfer from an R/3 backend, the delta data synchronization makes change information available for this initial dataset from the R/3 backend.

For this, in the CRM Server for each object class there are two groups of queues which control the data transfer.

• Via the queue group for the initial data download (R3AI*), the initial data is provided for the CRM Server from the R/3 backend.
• In the queue group for the delta data synchronization (R3AD*) change information is collected for the initial data.
  

During an initial data transfer the delta queues are suspended for each business object.

Once the initial data transfer is complete, the delta queues are released again and the change information forwarded to the CRM Server.

The server has been supplied with initial data through an initial data transfer.

To receive delta information, events are automatically activated in the R/3 backend when the initial data transfer is started. These cause the R/3 backend to provide another system with the data when specific events are activated (for example, create or change master data).

The data sent from the R/3 backend can be found in the inbound queue in the CRM Server (transaction code SMQ2). The data will only be saved in the outbound queue in the R/3 backend if the connection has been interrupted or the parameters have been set specifically to do this (transaction code SMQ1).