Z-Wave monitoring

Guardian Air monitors Z-Wave radio traffic to observe device activity in building automation and smart facility environments.

Overview

Z-Wave is a sub-GHz wireless protocol used in building automation, access control, heating, ventilation, and air conditioning (HVAC), and smart facility systems. Guardian Air uses a dedicated Z-Wave module to monitor Z-Wave radio traffic in the frequency band appropriate to the sensor's configured region. The module captures observable Z-Wave frames without joining any Z-Wave network. Z-Wave payloads are typically encrypted (S0 or S2 security); monitoring is limited to frame metadata and unencrypted traffic. Guardian Air synchronizes the data to Vantage for analysis.

What Guardian Air discovers

During Z-Wave monitoring, Guardian Air collects the following information from captured frames.

Table 1. Discovery data
Data point	Description
Frame direction	The direction of the frame as reported by the Z-Wave module: received (RX) from other devices, or transmitted (TX) by the module itself (for example, acknowledgements).
Payload	Parsed frame metadata and, where unencrypted, command class data used to identify device types and behavior.
Signal strength (received signal strength indicator (RSSI))	The received signal strength of the frame in dBm, used to estimate device proximity.
Channel hop index	The Z-Wave channel on which the frame was captured. Z-Wave Long Range uses a separate channel from classic Z-Wave.
Frame length	The byte length of the Z-Wave frame payload.
cyclic redundancy check (CRC) status	Whether the frame passed CRC validation, confirming frame integrity.

Frequency configuration

Z-Wave operates on sub-GHz frequencies that vary by region to comply with local radio regulations. Guardian Air applies the regional configuration during sensor onboarding in Vantage. The following table lists the frequency and region applied for each supported country.

Table 2. Z-Wave frequency regions by country
Region	Frequency	Supported countries
EU	868.4 MHz	Albania, Andorra, Austria, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Egypt, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Kuwait, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Montenegro, Netherlands, North Macedonia, Poland, Portugal, Qatar, Romania, San Marino, Saudi Arabia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, United Arab Emirates, United Kingdom, Vatican City
US	908.4 MHz / 916 MHz	Canada, Colombia, Guatemala, United States
ANZ	919.8 MHz / 921.4 MHz	Australia, Brazil, New Zealand
JP	922.5 MHz / 923.9 MHz	Japan
RU ¹	869.0 MHz	Macau
KR	920.9 MHz	Singapore, South Korea

Hardware

Z-Wave monitoring uses a dedicated Z-Wave module connected to the serial interface ttymxc3. Guardian Air processes only frames that pass CRC validation, ensuring that corrupted or partial frames do not generate false device discoveries.

¹ The RU region code is defined by the Z-Wave Alliance and does not correspond to Russia. It is applied to Macau based on compatible frequency regulations.