what is an ECC system
Can anyone please tell me what is an SAP ECC system , as i hav to integrate SAP CRM to SAP ECC system , i am getting blogs reltaed only SAP CRM to SAP Xi no ECC anywhere .
Please kindly help me here with nice reply about
1) ECC system and
2) How to integrate SAP CRM system to SAP ECC system through SAP PI 7.1
3) If IDOC to IDOC scenario is possible for above integration , please try to explain here .