SMLight SLZB-Ultima Review (Home Assistant)
Background
I've been using SMLight coordinators for quite some time in a Home Assistant environment and recently migrated from the SLZB-06MU to the new SLZB-Ultima.
My goal was simple: move all radio infrastructure away from USB, centralize everything over Ethernet/PoE, and evaluate whether the Ultima's multi-protocol approach offers real advantages over traditional coordinators.
After several weeks of testing, here are my impressions.
Why I Was Interested in the Ultima
Like many Home Assistant users, I started with USB coordinators directly attached to the host system.
They work well, but they also introduce limitations:
- USB passthrough complications in Proxmox and VMs
- Difficult hardware migrations
- Placement restrictions
- Potential USB interference
- Additional complexity in HA clusters
The SLZB series solves many of these issues by moving radio hardware onto the network.
The Ultima takes that concept even further.
Hardware Overview
The device combines multiple dedicated radios and networking components into a single platform.
Main Hardware
- ESP32-S3 management processor
- WIZnet W5500 Ethernet controller
- Power over Ethernet (802.3af)
- USB-C power input
- Passive cooling enclosure
- Dedicated radio architecture
One thing I appreciate is that SMLight physically separates radio components on the PCB instead of cramming everything together. For a device designed to run multiple wireless protocols simultaneously, that's a sensible design choice.
Zigbee Performance
The Zigbee radio is based on the TI CC2674P10.
In my testing:
- Device joins were quick
- Routing remained stable
- Response times were consistently fast
- Coverage was noticeably stronger than some older USB coordinators
The integrated amplifier provides excellent range, especially in environments with thick walls.
I tested the coordinator with Zigbee2MQTT and encountered no compatibility issues.
Verdict on Zigbee
If Zigbee is your primary protocol, the Ultima performs exactly as you would expect from a high-end network coordinator.
Thread and Matter
This is arguably where the device becomes most interesting.
Instead of simply exposing a Thread radio over the network, the Ultima can run OpenThread Border Router (OTBR) directly on the device.
In practice this means:
- Less dependency on the Home Assistant host
- Reduced network overhead
- Simpler architecture
- Reliable Matter-over-Thread onboarding
Matter devices paired quickly and remained stable throughout testing.
Compared with some USB-based Thread deployments, setup felt significantly smoother.
Z-Wave Support
The optional Z-Wave 800 Series expansion module allows the Ultima to become a true multi-protocol hub.
Benefits include:
- Better range than previous generations
- Long Range support
- Reduced 2.4 GHz congestion
- TCP-based integration with Z-Wave JS UI
For users already invested in Z-Wave, this removes the need for a separate dedicated controller.
USB-over-IP: A Feature More People Should Talk About
One of my favorite features is USB passthrough.
The integrated USB-A port allows compatible USB devices to be exposed over TCP/IP.
Why does this matter?
For Proxmox users, USB devices often become a headache when:
- Migrating VMs
- Moving containers
- Building HA clusters
- Replacing hardware
With USB-over-IP, the radio hardware remains fixed in its optimal location while virtual machines can move freely.
For virtualization enthusiasts, this feature alone may justify the device.
Additional Features
The Ultima also includes several extras that go beyond radio coordination.
IR Blaster
Useful for controlling legacy devices such as:
- TVs
- Air conditioners
- Audio equipment
Piezo Buzzer
Can be used for:
- Alerts
- Notifications
- Automation feedback
RGB LEDs
Exposed to Home Assistant and useful for:
- Status indication
- Visual alerts
- Diagnostics
GPIO and I²C
Advanced users can connect custom hardware directly to the device.
Software Experience
Configuration is handled through SLZB-OS.
Highlights include:
- OTA firmware updates
- Device diagnostics
- Network configuration
- Radio management
- WireGuard support
- Optional LTE backup support
The interface feels mature and provides enough detail for advanced users without being overwhelming.
What I Liked
Excellent Zigbee performance
Native OTBR support
PoE connectivity
Network-based deployment
USB-over-IP functionality
Optional Z-Wave expansion
Strong Home Assistant integration
Great fit for Proxmox environments
What Could Be Better
Higher cost than basic USB coordinators
Some advanced features may be overkill for smaller installations
Many users will never use all available expansion options
Comparison With Common Alternatives
| Feature | USB Coordinator | SLZB-06MU | SLZB-Ultima |
|---|---|---|---|
| Ethernet | No | Yes | Yes |
| PoE | No | Yes | Yes |
| Zigbee | Yes | Yes | Yes |
| Thread | Limited | Limited | Dedicated |
| Z-Wave Expansion | No | No | Yes |
| USB-over-IP | No | No | Yes |
| HA/Virtualization Friendly | Moderate | High | Excellent |
Final Verdict
The SLZB-Ultima is not aimed at someone looking for the cheapest Zigbee coordinator.
Instead, it targets Home Assistant users who want a centralized, scalable, network-based smart home architecture.
For standard Zigbee deployments, the SLZB-06MU remains an excellent option.
However, if you want:
- Zigbee
- Thread/Matter
- Optional Z-Wave
- PoE deployment
- USB-over-IP
- Better virtualization support
the Ultima offers a compelling all-in-one solution.
After testing it in a Home Assistant environment, I would consider it one of the most capable network coordinators currently available for advanced smart home users.
