A user-friendly interface box that maintains two-way communication with the SQFlex pump and monitors the operating conditions. The CU 200 is a combined status, control and communication unit especially developed for the SQFlex system.. Moreover, the CU 200 enables connection of a level switch placed in a water reservoir or tank. Built-in diagnostics indicate faults and dry-running, display operating status power consumption and level switch input. Communication between the CU 200 SQFlex Control Unit and the SQFlex Solar Pump takes place via the pump power supply cable. This is called mains borne signalling (or Power Line Communication), and this principle means that no extra cables between the CU 200 and the pump are required. It is possible to start, stop and reset the pump with the on/off button.