Access APIs across DCs

Hi experts,

I have 2 SCs which contains 2 DCs - EJB modules. Both these DCs are packaged into their respective DC EAR and deployed to AS Java. Please let me know the steps to access the class and its methods of one DC in another DC. Do I need to create public parts in source DC? If so is it only for ejb module or for ear as well? What should i expose in public part? Is it just the class file? How to include this in destination DC where i want to access this? Any runtime configuration settings?

Thanks in advance,

Rao