If the monitor displays a blue screen instead of video, check that the connections on the back of the call station and monitor are correctly inserted.
Make sure the two wires from the call station are inserted up to the stops on the CS/Call station terminal [7-2] (the polarity is not important).
Check that the cables are correctly inserted in the terminals by pulling slightly on them, then pass them through the notch provided (D).
Check that the call station cables are correctly inserted in the M+/M- terminals (A). The call station button should light up.