Zigbee - NXP KW41Z

The NXP KW41Z is a chip used for Bluetooth LE and 802.15.4 communications. To use it the development boards with Kismet, it must be flashed with sniffer firmware provided by NXP. It comes with this firmware by default.

The NXP KW41Z utilizes serial communications so no special libraries are needed for use with Kismet, however not all platforms have working serial port drivers (see below).

802.15.4 (Zigbee)

The 802.15.4 standard is a low-bandwidth low-power networking standard. A commercial implementation is Zigbee, however other devices also implement the 802.15.4 physical layer.

Detecting and classifying 802.15.4 networks can be challenging, as they may transmit infrequently. Often 802.15.4 networks report fragmentary network IDs, which may lead to multiple networks being identified as a single device; this is unavoidable due to how 802.15.4 addressing works.

802.15.4 channels

802.15.4 / Zigbee operates in up to 3 bands. You will need a device for each band. Most devices support the more common 2.4GHz band, with support for 800 and 900MHz being much rarer (currently only supported via the Freaklabs hardware).

8000European band, single channel
9001-11US / International ISM band
240012-26US / International ISM band

Channels are a fixed width and are identified only by channel number (ie 1, 12, 13, 14). There are no options for wide or fast channels in 802.15.4.

Despite sharing the frequency range with Wi-Fi on the 2.4GHz band, 802.15.4 uses a different physical encoding standard; a Wi-Fi card is not able to see 802.15.4 packets or networks, and an 802.15.4 device is not able to see Wi-Fi packets.

NXP KW41Z interfaces

NXP KW41Z datasources in Kismet can be referred to as simply nxp_kw41z. These devices appear as serial ports, so cannot be auto-detected. Each nxp_kw41z source must have a device option:


The NXP KW41Z can monitor both Bluetooth LE and Zigbee. By default it will try to monitor all,

To specify only Zigbee:


To specify only BTLE:


Source parameters

Naming and description options

All data sources accept the common naming and description options.

Device selection

device={ /path/to/serial/device }

The NXP KW41Z devices appear as USB serial devices, and serial devices can not be auto-discovered.

You must provide the path to the serial device associated with the nRF 51822 sniffer.

Phy type

phy={ btle } / { zigbee }

The NXP KW41Z can capture from BTLE and Zigbee. To only enable one phy, use the phy option.

Channel control options

Channel control for NXP KW41Z is only available in Zigbee mode.

channel_hop={ true } / { false }

Enable or disable channel hopping on this data source. Even if Kismet is (configured for)[/docs/readme/datasources/channelhop/#configuration] channel hopping.

channel_hoprate={ rate/sec } / { rate/min }

Change the hop rate for this source.

channel={ channel }

Set the source to a specific channel; combine with channel_hop=false to set the capture to a single channel forever.



channels={ channel1,channel2,...,channelN }

Set a fixed list of channels instead of probing the source for all supported channels.

The list of channels must be:

  • Comma separated
  • Contained in quotes



If defining datasources on the command line when launching Kismet, be aware that most shells will elide the quotes, leading to a setup error. You can avoid this by surrounding the source definition in single quotes:

kismet -c 'nxp_kw41z:device=/dev/ttyUSB0,name=Foo,channels="12,13,14,15"'