3.1.4 TopologyThe OPCMBTCP features a build-in Ethernet-switch, thus having two Ethernet RJ-45 connectors. This enables the possibility for connecting several Modbus TCPoptions in a line topology as an alternative to the typical star-topology.The two ports are equal, in the sense that they are transparent for the option. If only one connector is used, either port can be used.Illustration 3.2: Star topologyIllustration 3.3: Line topologyNB!For line topology please refer to section: “Recommended design rules” In a line topology all drives must be powered, either by mains or by their 24 V DC optioncards, for the build-in switch to work.Modbus TCP103