This problem isn’t a simple setting or software issue. It looks like an issue with the LCD assembly. I would recommend you send the unit to the factory service center for repair evaluation. (unless this is a black box process with a montior...then you might have a bad video cable)
No, the communication with the DFF1 sounder is by Ethernet. There is no "video" as you would know it as such. Your MENU options are distorted too. This isn't related to your sounder.