The smart-house system also provides a solution for when it is not possible to use wires. The SH2WBU230N is the wireless bus generator that can control wireless light switches and out relay modules. The wireless bus is based on the standard IEEE 802.15.4 @ 2.4 Ghz. Up to 250 modules can be managed by one SH2WBU230N. The open space operating distance is 700m.