Data Exchange Framework is designed to facilitate the transfer of data between two systems.
The system being read from is called the source system. The system being written to is called the target system.
Data Exchange Framework allows you to do things like:
|Read contacts from a CRM and create contacts in xDB||CRM||Sitecore|
|Update a contact in CRM using information from a contact in xDB||Sitecore||CRM|
|Create items in Sitecore that represent products in a catalog||PIM||Sitecore|
Typically, either the source system or the target system is Sitecore. However, Data Exchange Framework can be used to transfer data between any two systems.