Opener Brings an Open Source DECT NR+ Stack to Zephyr

Every few years a wireless standard arrives with genuinely good numbers and then stalls, because the only way to use it is a vendor's proprietary stack under a licence nobody wants to sign. DECT NR+ has been sitting in that position for a while. On August 27, 2026, the Opener Initiative published Opener, an open-source reference implementation of the DECT NR+ protocol stack under Apache 2.0.

• Opener implements the MAC and upper layers of DECT NR+ (formally DECT-2020 NR) in C, built for Zephyr RTOS
• The Apache 2.0 licence permits both research and commercial use
• DECT NR+ targets up to one million devices per square kilometre, sub-millisecond air-interface latency, and a 99.999% reliability goal
• Nordic Semiconductor's nRF91 series is currently the only off-the-shelf integrated hardware, including the nRF9151 DK and boards from Makerdiary, Norik Systems and Conexio

What DECT NR+ Offers That LoRa and Cellular Do Not

DECT NR+ occupies an unusual middle ground. It runs in licence-exempt spectrum at 1880–1930 MHz, with a European expansion to 3.8–4.2 GHz planned, so there is no carrier contract and no SIM. But unlike most licence-exempt options it was designed for density and determinism rather than range alone.

The headline capability is a rated capacity of one million devices per square kilometre with multi-year battery life for low-power sensors. Alongside that sits sub-millisecond air-interface latency and a 99.999% reliability target, which is the kind of figure normally reserved for licensed industrial wireless.

It supports point-to-point, star, and mesh topologies, carries both non-IP and IPv6 traffic, and handles random-access operation. Mesh matters here: it means coverage extends by adding nodes rather than by adding infrastructure, which is the same property that made the protocols in our Meshtastic, MeshCore and LoRaWAN comparison popular with hobbyists — but with a determinism budget those protocols do not attempt.

Why an Apache 2.0 Reference Stack Changes the Calculus

A standard without an open implementation is a specification, not a platform. Until now, evaluating DECT NR+ meant a commercial stack and a procurement conversation before you could write a line of code.

Opener is written in C for Zephyr RTOS and implements the MAC layer plus upper layers through Application Profiles, with code and samples published on the Opener Initiative's GitHub. The Apache 2.0 licence is the important detail — it is permissive enough that a product team can build on it without restructuring how they ship firmware. The project was developed with support from the OpenDECT-X project and research funding from Germany's Federal Ministry of Research, Technology and Space.

For anyone who has evaluated wireless MCU options recently, this shifts DECT NR+ from a line item in a comparison chart to something you can actually prototype in a weekend. Our low-power wireless MCU guide covers where it sits against nRF54L, ESP32 and RP2350 designs.

What Hardware Runs It Today?

This is the honest constraint. Nordic Semiconductor's nRF91 series is currently the only off-the-shelf integrated silicon for DECT-2020, so the practical hardware list is the nRF9151 DK, the nRF9151 SMA DK, and third-party boards from Makerdiary, Norik Systems and Conexio.

That is a narrow base, though a real one — we looked at one of those boards when Norik's nRF9151 dongle brought DECT NR+ to a USB port in July. A permissively-licensed stack is exactly the thing that makes a second silicon vendor's entry cheaper, so the single-source situation is more likely a starting point than a ceiling.

If you build industrial sensor networks, this is worth an afternoon. More single-board and embedded coverage lives on the mini computers page.

Sources: CNX Software — August 27, 2026; Opener Initiative on GitHub — August 2026.