RET System without Smart Bias-Ts (Home Run Cable) The system uses local or remote commands to adjust equipment for the desired antenna performance. System Operation 1. A laptop or network PC running Antenna Line Device Control (ALDC) software sends an AISG command to either the Portable Control Unit (PCU-KIT-4-xx) or Site Control Unit (SCU-xxx-01). 2. The command is forwarded to the internal or external RET unit via control feed communication cables. 3. The RET unit performs the command and sends positive feedback to the Control Unit. For more information about SmartTiltTM features and functions, please contact Amphenol Antenna Solutions sales and customer service. View the diagram for a RET System with Smart Bias-Ts.