D4i vs DALI-2
Both terms come from the DiiA and both sit on the same two-wire DALI bus. The difference is scope.
DALI-2: interoperable control
DALI-2 (IEC 62386) certifies that control devices — application controllers, input devices, LEDs — behave to a published specification so products from different vendors work together. It defines device types (DT1, DT6, DT8…) and a commissioning model.
D4i: control plus in-luminaire infrastructure
D4i assumes the device lives inside the luminaire and adds three things DALI-2 does not:
- A standard 24 V bus power supply (Part 250) so nodes are powered from the fitting.
- Self-description and memory — the node reports its type, serial and operating data.
- DiiA-issued certification tied to a unique ID, enabling plug-and-play Zhaga-D4i nodes.
Practical takeaway
If you are specifying a smart street-light or an OEM luminaire where sensors and comms nodes are added in the field, D4i removes the custom wiring and commissioning. For a fixed, wired DALI control loop, DALI-2 is enough. Read What Is D4i? for the background.