There are several bus systems with cables of different colors: The AI-SCS bus of the security system has a red cable and there are not any segments. The Auto-SCS bus of the automation and energy systems has a gray cable and it may have several segments (logical, and physical). And the AV-SCS bus in the audio video system has a white cable and a central audio matrix forming a star. The LAN bus has a CAT 5 cable and a central ADSL router. The VRV bus in air conditioning has a yellow cable to control the air conditioning units.