Digital Serial Interface (DSI), the forerunner of DALI, was developed in the late 80s and launched on the market in 1991.

The DSI protocol allows ballasts of different lamp types and technologies to be both switched and dimmed via the same control line. Powerless switching provides true flexibility in circuit design and management.

DSI has 255 steps in the dimming curve: matching the logarithmic nature of the human eye. Capable of dimming certain lamps to 1% of output, the DSI curve provides eye sensitive dimming that smoothly dims from maximum to minimum, without steps or any rapid change in light level.

The DSI bus has no polarity and is deemed non corruptible, and this has led to the development of five pole technology for the operation of digital lighting in lighting control modules.

DSI the only broadcast digital lighting bus.