The present document specifies the Remote Electrical Tilting Application Part (RETAP) between the implementation specific OM transport function and the RET Antenna Control unit function of the Node B/eNB. The document also specifies the Tower Mounted Amplifier Application Part (TMAAP) between the implementation specific OM transport function and the TMA control function of the Node B/eNB. It defines the Iuant interface and its associated signaling procedures for UMTS and E-UTRA.