The device combines the central functions of a KNX bus line: bus voltage supply with bus choke, KNX IP router and KNX IP interface with minimal space requirements. Comprehensive diagnostic functions. The KNX IP router in the LineMaster enables telegrams to be forwarded between different lines via a LAN (IP) as a fast backbone. The device also serves as a programming interface between a PC and the KNX bus (e.g. for ETS®).