SMLIGHT
SMLIGHT SLZB-06M
- Zigbee
Verified September 2026
The Zigbee2MQTT community's favourite coordinator: Ethernet with PoE lets you mount it centrally in the house instead of tethering it to your server, killing dead zones. At £61 it's nearly double Home Assistant's own ZBT-2/SkyConnect (£30-35) or the ConBee III (£37) — and if your switch isn't already PoE-capable, add £10-15 for an injector. That premium only pays off in larger UK houses or multi-floor flats where the server sits nowhere near the devices; USB mode is available too, but then you're paying more than ZBT-2 for the same result. Works with Z2M and ZHA over the network.
In Home Assistant
| Control | Type | What it does |
|---|---|---|
| Coordinator status | Diagnostic (web UI only) | SLZB-OS dashboard shows online/offline status and last-message timestamp; not exposed as an HA entity — check the device's own web UI if the network looks unresponsive. |
| Connected device count | Diagnostic (web UI only) | Live count of joined Zigbee devices, useful for spotting a mesh that's silently dropped nodes without opening Z2M. |
| Link status | Diagnostic (web UI only) | Reports whether the unit is on Ethernet, PoE, or Wi-Fi and the link speed — handy for diagnosing PoE injectors that power the device but never bring up a stable link. |
| Core firmware version | Firmware (web UI only) | ESP32 network/Wi-Fi/LED module, updated independently of the Zigbee radio firmware. |
| Zigbee firmware version | Firmware (web UI only) | EFR32MG21 EZSP radio firmware; version determines EZSP protocol level and therefore ZHA/bellows compatibility. |
Both Z2M and ZHA talk to it over a raw TCP socket (port 6638, EZSP adapter, 115200 baud) rather than USB — SLZB-OS assembles complete EZSP frames on the device before forwarding them, giving lower link-error rates than a naive serial-over-IP passthrough. One real gotcha: SMLIGHT's newer coordinator firmware builds moved to EZSP protocol v18, which ZHA's bellows library doesn't fully support yet, so flashing the latest Zigbee firmware can leave ZHA connected but blind to devices even though Zigbee2MQTT works fine on the same firmware — check compatibility before updating if you're on ZHA. Both the ESP32 core (network/Wi-Fi/LED) and the EFR32MG21 Zigbee radio can be firmware-flashed remotely from the device's own web UI with no physical access needed.
Specs
- chip
- Silicon Labs EFR32MG21 (Zigbee radio) + ESP32 dual-core 240MHz/6MB (network/Wi-Fi/LED control) + CP2102 USB-UART bridge + LAN8720 Ethernet PHY
- size
- 160x22x24mm slim case (<22mm wide)
- power
- PoE via IEEE 802.3af (15W standard, actual draw well under that) injector or PoE switch, or USB-C at standard low USB-stick draw — SMLIGHT doesn't publish an exact wattage figure for either mode; USB and Ethernet are opto-isolated so both can be connected at once
- range
- No official metres figure published; SMLIGHT markets the +20dB amplifier and external antenna as giving stronger link quality than USB coordinator sticks, and multiple units can be run as routers to cover multiple buildings on one Zigbee2MQTT network
- extras
- Experimental Matter-over-Thread firmware available (one radio protocol at a time)
- antenna
- External, rotatable 3D antenna — 5dB antenna plus a +20dB onboard amplifier stage on the Zigbee radio, unlike the ConBee III's internal fixed antenna
- connectivity
- Ethernet with PoE, Wi-Fi, or USB-C (three modes, switchable from the web UI or the physical button)