Network module for up to 16 network devices. Plastic protective housing with LED displays for speedy indication of the operating status. The transmission is via Token-Passing protocol, similar to DIN 19245-1 (Profibus) with loop topology, interruption and short-circuit tolerance. Modules are locked mechanically without screws in the slots, just quick & easy. Hot plugging and automatic recognition of modules just by Plug & Play, makes start-up and maintenance easy to handle.