DALI-2 input and output devices for building a DALI system: push-button couplers that let ordinary switches and push buttons control a DALI line, couplers that bring motion detectors and 0-10 V light sensors into it, and DALI relays and dimmers. Most draw power from the DALI bus, need no mains connection and fit into flush-mounted boxes or luminaires, and they are DALI-2 certified for mixing with other makers' devices.