DALI-2 Certified: What It Means for Your Spec

All QTL DALI drivers are DALI-2 certified. DALI is the Digital Addressable Lighting Interface, an open digital protocol that gives every fixture on a two-wire bus its own address. Every certified product has been tested against DiiA’s (Digital Illumination Interface Alliance) DALI-2 test specifications, with results verified by DiiA not just QTL’s own QA process. When you see the DALI-2 mark on a QTL driver, you can be confident that it has been tested to the same specification as every other certified device on the bus. DALI-2 certification allows lighting designers, custom integrators, and engineers to specify a mixed system of products from multiple manufacturers on any project, commercial or residential.

Why does DALI-2 exist?

DALI-2 is the certification program that replaced DALI-1’s self-declared compatibility with mandatory testing of DALI lighting control gear.

DALI-1 let two manufacturers both claim compliance and still fail to talk to each other on the same bus, the two-wire control line that links every device in a DALI system. The spec left too much open to interpretation, so a driver from one brand and a controller from another could install fine and fail months later. This could lead to flicker, dropped addresses, and a fixture that stops responding to scenes. Nobody could prove whose gear was at fault, because “DALI-compatible” was a claim, not a test.

What does DALI-2 certification get you?

Tested bi-directional communication, backward compatible with most DALI-1 systems already in the field
Up to 64 short addresses, 16 groups and 16 scenes on a single bus (as in DALI-1)
Certified DT8 channels for color-tunable and RGB dimming control
Tested two-way status monitoring, so a controller can query a fixture and get an answer back instead of assuming the command landed

DALI-1 could already answer queries, but responses weren’t certified, so they varied by brand. DALI-2’s tested bi-directional spec means the system talks back, with confirmation, status and diagnostics in place of guesswork on a callback.

How many fixtures fit on one DALI bus?

DALI classifies drivers by device type, or DT. DT6 is standard LED dimming, and DT8 adds color control. The 64-address ceiling counts channels, not fixtures. With DT6, every channel consumes an address. That is why an RGBW job drops a bus from 64 devices to 16. A DALI-2 DT8 device collapses any multi-channel fixture back to a single address, which is the practical reason DT8 matters.

Our 2-wire Warm Dim strip, where color temperature follows intensity on a single curve, acts as a one-channel LED and only requires a DT6 decoder and one address. Our 3-wire Tunable White strip, where you have independent control of both color temperature and intensity, acts as a two-channel LED and requires two addresses with DT6, or one address with DT8.

DALI vs. 0-10V: which should you specify?

0-10V dimming is the older, simpler protocol: a low-voltage analog signal tells the driver to dim up or down, with no addressing and no status feedback. It’s still a sound choice for a single zone with basic on/off-and-dim needs and a tighter budget.

DALI is built for integrated projects where you want active information back from your fixtures, like knowing when one has failed and stopped turning on, or how much power it’s using. 0-10V is a simpler control protocol, with no two-way communication with the decoders or fixtures.

DALI lighting control earns its keep once a project needs individual fixture addressing, scenes, or confirmation that a fixture responded. If you’re running one dimming level per room, 0-10V power supplies still make sense. If you’re commissioning a mixed-brand system or need to know a fixture is online, DALI-2 is the protocol built for that job.

Which QTL power supplies use DALI-2 certified control gear?

Five QTL families carry DALI. Dimming depth follows the family, not the device type, so it is the first column to check against the application.

Family	DALI dimming	Specify it when
QTM (DC)	0.1%	Indoor, surface or recessed. Enhanced dimming protocols and capacity. Housing can ship ahead of the tray for rough-in.
QOM (DC)	0.1%	Outdoor rated, surface mount. Precision dimming with enhanced capacity.
QT-CAB	0.1%	For larger projects that need more drivers in one enclosure. Fits between standard studs, and the housing can ship ahead of the tray for rough-in.
QZ	0.2%	Most cost-effective and compact. Surface mount only.
Q-SET+QZ	0.2%	Direct burial and outdoor rated. Installs in the Q-VAULT-5 enclosure.

QZ-DALI-DT6 & DT8: control at the driver level

The QZ-DALI-DT6 and QZ-DALI-DT8 are Class 2 LED power supplies built for dimmable LED control and rated to 96W. They’re programmable with any DALI-2 certified controller, with no proprietary handshake required.

Most projects still commission and address drivers from the DALI controller, without touching each one. The NFC app is handy for adjusting output voltage or checking the address on an individual driver.

DALI-2-certified power supply cabinets

QT-CAB, QTM, and QOM are power supply cabinet solutions that house multiple power supplies available in DALI-DT6 and DALI-DT8 versions for DALI-2 projects that need multiple zones and more wattage in one central location.

Each driver ships prewired to its own decoder, so the installer lands home runs on terminal blocks instead of wiring decoders in the field. Projects with independently controlled areas, like retail departments or hospitality zones with distinct scenes, get there without field-wiring every decoder by hand.

Wiring runs into QTL terminal blocks rather than onto the driver itself, so an installer can land multiple home runs on one block up to the 100W driver rating.

The QT-CAB-eLED+DALI-DT8 and QT-CAB-eLED+DALI-DT6 have the largest capacity, housing up to seven 100W constant-voltage LED drivers, each paired with DALI-2 decoders for color-tunable and RGB control.

What does QTL supply, and what comes from others?

QTL supplies the power supply center, the driver stage and the DALI in and out terminals. The DALI controller and the DALI bus power supply are supplied by others. They aren’t on QTL’s bill of materials, but the system can’t be commissioned without them, so make sure both are specified for the project.

How does DALI certification simplify a project?

Specifying DALI-2 certified gear makes the job simpler now and quieter later. You can choose products on design merit instead of vetting every driver and controller pairing yourself, and the certification listing gives you something concrete to show a client or an owner’s rep when they ask how you know the products work together. Down the road, a certified system is easier to expand, because new certified devices can join the bus without replacing what’s already there, and it’s less likely to send you back to the site to chase a fixture that stopped responding. Spec it once and put your time into the next project.

See all QTL DALI-2 certified power supplies

FAQs

Can QTL DALI-2 drivers run third-party fixtures?

Usually, yes, as long as the fixture matches the driver’s output voltage and stays within its wattage. DALI runs between the controller and the driver, so the fixture itself is never on the bus. QTL still recommends requesting a sample and testing the combination first. Another manufacturer’s on-board electronics can interfere in ways certification does not cover, and a bench test costs less than a callback.

Is DALI-2 backward compatible with DALI-1?

Generally, yes. DALI-2 drivers work with existing DALI-1 controllers, and DALI-2 controllers can run DALI-1 drivers already in the field, without the newer DALI-2 features. You can add DALI-2 certified drivers to a DALI-1 system without replacing the bus. DALI-2 sensors and keypads need a DALI-2 controller.

Does DALI-2 dim deeper than 0-10V?

No. QTL DALI power supplies dim to 0.1% or 0.2% depending on the family, and QTL 0-10V supplies reach the same depth. Choose DALI for assigning addresses, status feedback and channel efficiency. Dimming depth is a property of the power supply family, not the protocol.

What is DALI DT6?

DT6, short for Device Type 6, is the DALI category for standard dimmable LED drivers. A DALI-2 certified DT6 driver accepts standard dimming commands from any certified controller and answers status queries from the controller, without a manufacturer-specific handshake or proprietary software needed to commission it.

What is DALI DT8?

DT8, short for Device Type 8, is the DALI category built for color control, covering tunable white, RGB and other multi-channel color outputs. A DT8 driver or decoder translates DALI-2 commands into the specific channels a color-tunable or RGB fixture needs, so color and intensity run on a single address.

Does DALI-2 certification cost more to spec than an uncertified system?

Certification is a testing requirement, not a premium feature, so DALI-2 certified products compete on price like any other DALI gear on the market. The cost difference shows up later, in reduced troubleshooting time, fewer callbacks, and less guesswork on mixed-brand installs.