Weidmuller WI-I/O-9-U2: Wireless Mesh I/O & Gateway User Manual V1.2.2 - Manual (Page 21)

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Figure 5 - Earthing
2.3 Radio
The following radio variants are available in the WI-I/O 9-U2 dependent on the country
of operation.
2.3.1 900 MHz Spread Spectrum radio
The radio uses frequency hopping spread spectrum modulation, which is a method of
transmitting radio signals by switching the carrier among many frequency channels,
using a pseudo random sequence called a hop set.
There are two hopsets; each one using a different pseudo random sequence of 50
channels, that cycle through the sequence and switch to a different channel after each
radio transmission.
The radio operates in the 902-928 MHz ISM band which is split into two frequency
bands, 902-914 MHz (Low) and 915
–928 MHz (High).
In America and Canada, the WI-I/O 9-U2 can use both high and low bands - however in
other countries, i.e. Australia only the 915-928MHz band is available
Some countries use fewer channels, e.g. New Zealand uses 18 Channels in the
frequency band 922.75 -927.00MHz.
The frequency band can be changed in countries that allow the two bands to be used by
selecting the Hopset on the Radio Configuration webpage of the module. The Hopset
will only display the Frequency bands available for the model and country.
The receiver is continually scanning all channels within the hop-set and when a valid
data packet is received; it locks on to the channel and receives the data.