Difference b/W SAP JRA Interface & SAP ERP System Interface Action Block

Hi All,

I am sorry to pop up with so many questions related to xMII 12.0. But after exploring all the help i find sdn forum to be best to answer my queries

What is the difference b/W SAP JRA Interface & SAP ERP System Interface Action Block in SAP xMII 12.0

What was the requirement of SAP JRA Interface action block even when BAPI's could be pulled through JCO interface.

Please respond

Thanks & Regards

Namita