When an FRnet I/O module is used as a MagicWire module, a host module with mode number SA0 must exist. In one FRnet network, there is one and only one host controller. The FR I/O module can have the jumper set to be SA0 a host controller. Those modules of the same group can have data transmission between them. The modules of different group can't communicate with each other. But different group modules can be connected to the same FRnet network. One FRnet input module can work with one or several FRnet output modules. But those output modules should be set to the same address number. Refer to related literatures of MagicWire MA series for detail information.