The Data Conversion between Sender and Recipient Set-Up tool maps field contents from a sender to a recipient field. You can then distribute organizational units, measurement units or customer-specific field contents from one system to another.
It is a general tool for defining and maintaining rules in ALE.
You can only use this tool if you use the Web Application Server (SAP_BASIS) with SAP application components.
In the ALE implementation guide (IMG) choose:
Transaction SALE ® IDoc Interface/Application Link Enabling (ALE) ® Model and Implement Business Processes ® Set-Up Conversion between Sender and Recipient
Proceed as follows:
...
1. Create rule: The rules are defined per segment.
2. Maintain rule: Rule maintenance specifies conversion rules at field level.
3. Assign rule to a message type: The assignment specifies when the rule is to be applied. This is sender/recipient and message type specific.
See also the documentation of the individual work steps in the IMG.