Nabu Casa Home Assistant Connect ZBT-2 - Official Home Assistant Zigbee 3.0 and Thread USB Coordinator (Silicon Labs MG24, 4.16 dBi SMA Antenna)

Brand: Nabu Casa (official Home Assistant hardware)

Manufacturer reference: NC-ZBT-9741

Radio chip: Silicon Labs EFR32MG24

USB-serial bridge: ESP32-S3

Supported protocols: Zigbee 3.0 or Thread (selectable, not simultaneous)

Matter compatibility: yes, via Thread Border Router (OTBR) and Home Assistant

Radio frequency: 2400 - 2483.5 MHz (2.4 GHz band)

Transmit power: 10 dBm (Europe) / 8 dBm (other regions)

Antenna: external, SMA connector, 4.16 dBi gain, omnidirectional, removable

OTA updates: supported for compatible Zigbee devices

Connectivity: USB-C (power and data)

Power supply: 5 V DC, 500 mA

Software compatibility: ZHA (native Home Assistant), Zigbee2MQTT, OpenThread Border Router

Dependency: requires a Home Assistant server (Green, Yellow, Raspberry Pi, NUC…)

Dimensions: 83 × 83 × 179 mm (antenna included)

Weight: 157 g

Operating temperature: 0 °C to 65 °C

The ZBT-2 enters a Zigbee/Thread market already well-occupied by SMLight and Sonoff, but it has an advantage no one else does: it's signed by the Nabu Casa team, the very same team that develops Home Assistant. The integration is undeniably seamless. I plug the dongle into my HA server, the interface directly offers to create a Zigbee 3.0 or Thread network, the firmware flashes itself, and the Open Thread Border Router installs automatically if I choose Thread. It's total plug-and-play, without any YAML manipulation or third-party firmware. ZHA compatibility is obviously perfect, and Zigbee2MQTT also works very well via the "Custom" option during setup.

On the hardware side, Nabu Casa has clearly upgraded compared to the SkyConnect (ZBT-1). The Silicon Labs EFR32MG24 chip is a generation above the old MG21, and most importantly, the external antenna uses a standard SMA connector with a gain of 4.16 dBi. This means the antenna is removable and replaceable, a real plus for those who want to install the dongle in a rack or behind a closet door with a remote antenna. Radio performance is excellent, devices pair faster, and mesh stability is impeccable in my tests. The design, which assumes it will be placed on furniture rather than hidden behind the server, is a choice I like, although you can always plug the dongle into a USB extension cable to move it away from sources of interference.

However, two limitations must be acknowledged. First, no multiprotocol: it's impossible to run Zigbee AND Thread simultaneously on the same key. Nabu Casa accepts this choice for stability reasons, and they are right in principle, but if you want both networks, you need to plan for two coordinators. Second, unlike the SMLight SLZB-06M, which remains the most serious competitor, the ZBT-2 has neither Ethernet nor PoE. It's a pure USB-C dongle, so it's impossible to extend it to the other end of the house via the network.

Overall, for its price, the ZBT-2 is one of the best Zigbee coordinators on the market for a Home Assistant user. Full openness (open source, internally accessible, no clips or glue), replaceable SMA antenna, MG24 chip, official firmware updated by the HA team, OTA updates for Zigbee devices. The only real criticism remains the absence of PoE. I rate it 4.5/5: solid hardware, Home Assistant integration that has no equivalent among competitors, and a purchase that funds the Open Home Foundation in the process.