Control unit for supplying the audio and video components of the Gira door communication bus. Supply of the reverse polarity and short-circuit protected 2-wire bus when using video components such as color camera, TFT color display. Up to 2 door stations with colour camera and 28 home stations with TFT colour display can be supplied via video control unit. In total, up to 15 color cameras can be controlled by the video control unit (5 door stations video and 10 TKS camera gateways), from which two door stations with color cameras can be supplied with voltage from the video control unit. The other color cameras must each be operated with their own power supply for door communication. Self-resetting electronic short-circuit and overload detection of the operating voltages and the bus connection. Buttons for system and door opener programming. LED status indicators for operation, overload, system programming and door opener programming. AC 12 V output for power supply