manual
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However, the channels in the ISM band overlap. For example, with reference to the
actual radio output of an access point, we find that an access point transmitting
on channel three also emits a signal on the neighboring channels 1, 2, 4, and 5. This
means that other WLAN components communicating on any of those four chan-
nels will receive interference. This happens whenever the components transmit data.
Data transmission generally occurs even when no user data is transported over the
network — in other words, when the network is idle — because management informa-
tion, beacons, keep-alive packets and the like still have to be transported at regular
intervals. This phenomenon is called near-channel interference.