Integration Using Services 
You can use certain service operations to supply one or more applications, for example, a POS server, with data from SAP ERP. This way you can run applications, to which you are sending data, or with which you wish to reconcile data, independently of the SAP ERP system.
Using a service implementation, you define with which service operation and exactly how your business objects are to be transferred to applications.
Using filter objects, you can filter the data to be transferred according to certain criteria in order to supply the receiving application with only the required information. Here you can specify the filter criteria explicitly to select the relevant data (for example, all articles from selected article groups) or to use implicit system checks or filters (you can, for example, filter all article-store combinations that satisfy the listing check).
The filter objects used by a service operation (one or more) are defined by the service implementation. You can use a filter object in multiple service implementations so that you only have to define common filter criteria once.
To check which service operations are available, see Customizing under .
To guarantee orderly use of the Enterprise Services, you must first define for each application:
which business objects are to be transferred to the application You define the business objects indirectly using the appropriate service implementations and their messages.
which explicit and implicit filters are to be taken into account in the processing of data for each service implementation (optional).
For this you must make all required settings in Customizing for Retail Enterprise Services under .
For more information on the Customizing settings, see the Customizing documentation under and also in the documentation on each of the Customizing activities.
If you have defined explicit filters in Customizing and wish to use these, you must define the relevant filter criteria in transaction WESF before you can transfer data using transaction WESOUT.
You can activate implicit filters only by assigning them to an application in Customizing. If you have made such an assignment, the system always carries out the corresponding checks when data is processed by way of transaction WESOUT. If there is no assignment of filter objects and explicit or implicit filters, the system assumes that no restriction is intended.
Service implementations that process messages both for stores and store-specifically, enable one-time processing of data that is to be valid for multiple stores. This way you can optimize the runtime when processing mass data and you can reduce the data volume. To do this, you must use transaction WESREFS to assign the stores for common data processing to a reference store before you start the data transfer with transaction WESOUT.
To configure and process outbound messages on transfer of data from SAP ERP to external applications, and then to check the progress of the data processing, you can use the following transactions:
Definition of Explicit Filter Criteria for an Application
In this transaction you configure the explicit filter criteria that are to be taken into account when you use transaction WESOUT to process the data of the outbound messages for an application.
Maintenance of Reference Store to Store Assignment
You can use this transaction if you want a message, that is to be valid for multiple stores, to be processed only once.
Generation of Messages for Application
With this transaction, you can generate outbound messages for the service operations for which you have assigned service implementations to applications.
Evaluation of Application Log for Outbound Messages
In this transaction you can display logs that provide information on the progress of the data processing.
The following graphic illustrates the relationship between Customizing settings and the transactions WESF and WESOUT using an example:

You wish to supply the two applications A1 and A2 with data:
Application A1 is to receive the relevant data by way of the service operation of service implementations S1 and S2. When S1 is processed, that only data to be selected is that which has satisfied the filter criteria O1 and O2. For S2, the filter criteria that apply are O2.
A2 is to receive data by way of the service operation of service implementations S2 and S3. For S2, the filter criteria that apply (O3) are different to those that apply to application A1. The system check (implicit filter) F3I1 is to remain active for processing of S3.
In Customizing you can make use of the service implementations S1, S2 and S3. These use filter objects and filters (explicit and implicit).
You define the applications A1 and A2 in Customizing and assign the service implementations that you wish to use. You also determine which filter objects and, in particular, which filters and filter criteria are to be used.
If you use explicit filters you must define corresponding criteria in transaction WESF. These filter criteria, and the implicit filters that you have activated in Customizing for the application, are taken into account when you process the data using transaction WESOUT.