I am currently working on CEN/XFS. I have read the documentation. As far as I know, for each device (for example: Card Reader, Dispenser, Pinpad...) there is a special library (.dll) for interacting with CEN/XFS
Where can I get a library (.dll) for a specific device (for example, for a card reader)?
The dll is usually provided by the device manufacturer. It then gets loaded by the Xfs Manager. If you are implementing a service provider for a specific device you have to implement this dll.