The two basic components of a Wi-Fi network are a computer device outfitted with a low-power radio and another radio-equipped gadget known as an access point, which is wired to the Internet or a local network. The two communicate with each other over a free slice of the radio spectrum reserved for consumer use and inhabited by microwave ovens and cordless phones.
The article from The Technology Review on how wi-fi works includes an animation explaining how the behind the scenes go on.
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