You need Cinegy Licensing Service installed and a hardware dongle or software license for operating Cinegy Prompter; if you launch it without the license, an error message will appear:
If the dongle is removed while Cinegy Prompter is launched and connected, the red "NO DONGLE" sign appears at the bottom of the Prompter screen. In a few seconds it starts blinking, and after that the text scrolling stops. As soon as the dongle is inserted, the "NO DONGLE" sign disappears. To continue the text scrolling press the "Play" button.