At its core, a Z-Wave stick is a simple piece of hardware equipped with a Z-Wave chip that acts as a radio transmitter. This device enables communication between your computer or hub and your Z-Wave devices, serving as a bridge for transmitting and receiving commands within your smart home network. Our team at Zooz is committed to providing hardware support for the Z-Wave stick.

If the stick is recognized on your computer or via tools like Silicon Labs' Simplicity Studios PC Controller software, it confirms that the hardware is functional. Any other issues you may experience with your system or set-up will most likely be related to other components of your installation like the home automation software or the computer you're running it on. Since many software providers offer limited support, we've compiled a list of commonly asked questions and some troubleshooting tips in this article to make things a little easier for you. With a DIY set-up including third party hardware and software, there are many factors that can cause issues. For these software-specific needs, we recommend utilizing the robust resources and communities provided by Home Assistant. Read more about Home Assistant support resources here.

Set-Up Tips

• If this is a new set-up and you believe the stick is the issue, please let us know if the stick is recognized in your computer. If yes, then please try the stick in the Simplicity Studio's PC Controller software. The instructions for installing PC Controller and adding the stick are listed here.
• If the stick is recognized correctly, and you can add a Z-Wave device, then the stick is not the issue and you would need to utilize Home Assistant resources for assistance. 
• Try another USB port to rule out any power related issues.
• Ensure your stick is running on a USB extension, as per Home Assistant recommendations

USB2 or USB3 ports?

• USB-3 is only needed when mass storage is used. Other than that, USB-2 works just fine. Z-Wave has low bandwidth and USB-2 is 480Megabit. USB3 can actually be a detriment to most users. It causes interference with wireless signals and is the main reason it's recommended to use an extension cable for any dongles used to add Z-Wave.

USB Extension Inquiry

• Generally speaking, the longer the cord, the higher the resistance, which can lead to a loss of signal strength. This can result in slower data transfer rates, increased latency, and potential packet loss. In extreme cases, it may even cause the connection to drop entirely.
• The passive USB cable extension recommendation is less than 10 feet (3 meters). You can extend farther using an an active USB extension cable instead.

Determining Network Key

• The network key should be generated during the set-up. The Serial Port for the MQTT should be /dev/ttyUSB0, then go to the Network Key next to it and click the refresh button so a network key can be generated, then click Save.

How should the stick display?

• The stick should be detected as a ttyUSB serial device. Whether a Linux machine detects a device as a ttyACM device or a ttyUSB device depends on how the device's serial interface chip firmware announces itself. ttyUSB is meant for a USB serial device, while ttyACM was really meant for USB modems. Both work effectively as an interface to the Z-Wave chip's serial communication channel.

TX Power Levels

• These can be set up in different 3rd party software like Home Assistant, etc.
• Default: Tx Power Level Normal -8 dB and Tx Power Level Measured 0 dB for the ZST39 USB stick

Changing Z-Wave Frequency

• Since SDK 7.17, the region for the stick is always set by the controller software and not "baked into" the firmware anymore. This means you can use the software to set the frequency. Our technicians have confirmed this on Home Assistant running Z-Wave JS UI, as well as HomeSeer running the Z-Wave JS Front-end. We've included a screenshot from the Z-Wave JS UI below:

NVM Backup/Restore

• 500 series sticks cannot be backed up and restored to the 700 or 800 series sticks due to SDK limitations.

• 700 can be backed up and restored to the 800 series ONLY via Z-Wave JS. We DO NOT recommend PC Controller for these NVM backups.

  • Here's why: The 800 series has a different NVM memory layout than the 700 series. The 700 series NVM is 48 KB divided into two sections, one for the Z-Wave protocol related data (nodes, routes, etc.), one for the application related data (radio settings, etc.), while the 800 series NVM is only 40 KB, and application and protocol data is stored together in a single section.
    • PC controller does not care about this distinction and just writes the raw NVM data. If you restore a 700 series NVM onto an 800 series controller via PC controller, you will end up with an incorrect layout, which the 800 series firmware cannot read, and 8 KB of missing data.
    • Z-Wave JS (UI) detects the NVM layout of the target controller first, and if that layout is supported, it will parse the source NVM and rewrite it into the new target format.
    • A lot of users have used Z-Wave JS's NVM backup/restore to migrate from older sticks to ZST39-800, since it's currently the only way to do this migration without having to re-pair all devices.
    • For detailed instructions, we recommend this helpful thread in the community forum. You will need to be using the Z-Wave JS UI in order to complete it.

Firmware Updates

• Should I update my stick? If you're not experiencing any issues with your network or controller, there's no need to update the firmware. It's recommended that the Z-Wave stick is treated like bios in your computer and updated only if absolutely necessary to avoid service crashes.
• What about the Home Assistant warning? The 7.19 SDK released by Silicon Labs earlier this year can indeed sometimes produce controller lock-up issues, but only in edge cases. If you're not experiencing any issues with your network or controller, you can ignore the warning and there's no need to update the firmware. It's recommended that the Z-Wave stick is treated like bios in your computer and updated only if absolutely necessary to avoid service crashes.
• How can I update my stick? We recommend using Silicon Labs PC Controller software to update the Z-Wave stick. Since Home Assistant is not a Z-Wave certified software, and since we have seen many issues with the OTW process on Home Assistant, it is always recommended to use Simplicity Studio's PC Controller software to perform the OTW updates. We cover that in detail here as well. Instructions and firmware files are found here: How to Perform an OTW Firmware Update on Your ZST39 800 Long Range Z-Wave Stick

Troubleshooting for sticks bricked on NVM/Backup or via Firmware Update Done from Home Assistant:

We found this fix to be helpful for most users:

• Go to Z-Wave JS UI.
• Select Settings tab
• Select "Z-Wave" section
• Enable "Bootloader only"

• Restart Home Assistant.
• Select: Z-Wave JS UI > Control Panel tab > Hamburger menu (blue bottom right corner, is three lines until you click it and it turns into an X)
• "Advanced actions" (purple wand)

• Then under "General actions" select: 
  • "Firmware update OTW" and chose the firmware file.
• Once it's complete (prepare for a long wait), restart Home Assistant. 

Please let us know if you have any tips you think we should add!