The Unlicensed National Information Infrastructure (U-NII) radio band is part of the radio frequency spectrum used by IEEE-802.11a devices and by many wireless ISPs. It operates over three ranges: Wireless ISPs generally use 5.725-5.825 GHz. U-NII is an FCC regulatory domain for 5- GHz wireless devices. U-NII power limits are defined by the United States CFR Title 47 (Telecommunication), Part 15 - Radio Frequency Devices, Subpart E - Unlicensed National Information Infrastructure Devices, Paragraph 15.407 - General technical requirements. Regulatory use in individual countries may differ. The European HiperLAN standard operates in same frequency band as the U-NII. Except where noted, all information taken from Annex J of IEEE 802.11-2007 modified by amendments k, y and n. Countries apply their own regulations to both the allowable channels, allowed users and maximum power levels within these frequency ranges. Consult your local authorities as these regulations may be out of date as they are subject to change at any time. In 2007 the FCC (United States) began requiring that devices in operating in channels 52, 56, 60 and 64 must have dynamic frequency selection (DFS) capabilities.