Dear friend, I have to establish communication with ' CPU TWDLC DE 40 DRF ' (Schneider Electric). On reading the documentation, It comes to my knowledge that three programming cables are available - 1. TSX CUSB 485, 2. TSX CRJMD 25 and 3. TSX PCX 3030 What is the difference among these cables. Which cable I should purchase. Any information regarding this will be appreciated. Thanks and Regards Shivam