The Festo CPX-M-FB34 is a bus node that sits at the head of a CPX terminal, handling the fieldbus communication for the I/O slices that follow. It runs at 100 Mbit/s — fast enough for most mid-size machine cells — and takes 24 VDC nominal, with the supply range stretching from 18 V to 30 V to handle a sagging line without dropping the bus.
Configuration is done through the DIL switches on the front; there's also a slot for an optional memory card if you want to store the node parameters and swap the unit without a laptop. The ambient rating of -5 °C to 50 °C covers most cabinet environments, and the storage range of -20 °C to 70 °C means it can sit on a shelf in an unheated warehouse between jobs.