The rules defining these devices were announced on Election Day (November 4, 2008) and published by the Federal Trade Commission (FCC) in a Second Report and Order on November 14, 2008. Much of the work behind the definition of these devices was done by the White Spaces Coalition.
Fixed and personal/portable devices are defined. "Fixed devices" may use any of the vacant U.S. TV channels 2, 5-36 and 38-51 with a power of up to 1 watt (4 watts EIRP). They may communicate with each other on any of these channels, and also with personal/portable devices in the TV channels 21 through 51. "Fixed devices" must be location-aware, query an FCC-mandated database at least daily to retrieve a list of usable channels at their location, and must also monitor the spectrum locally. They may transmit only within the TV channels where both the database indicates operation is permissible, and no signals are detected locally. Personal/portable stations may operate only on channels 21-36 and 38-51, with a power of 100 mW EIRP, or 40 mW if on a channel adjacent to a nearby television channel. They may either retrieve a list of permissible channels from an associated fixed station, or may accept a lower output power of 50 mW EIRP and use only spectrum sensing.