In the United States the government agency responsible for regulating communications is the Federal Communications Commission (FCC). Control of electromagnetic interference is outlined in Part 15 of the FCC rules and regulations. FCC rules decree that any spurious signal greater than 10KHz be subject to these regulations. The FCC further specifies the frequency bands in which these spurious emissions must be controlled according to the type of emission. Radiated emissions, i.e., those radiated and coupled through the air, must be controlled between 30MHz and 1000MHz. Conducted emissions, i.e., those RF signals contained within the AC power bus, must be controlled in the frequency band between 0.45MHz and 30MHz. The FCC further categorizes digital electronic equipment into Class A (designated for use in a commercial, industrial, or business environment excluding residential use or use by the general public) and Class B (designated for use in a residential environment notwithstanding use in commercial, business and industrial environments). Emission standards are more restrictive for Class B devices since they are more likely to be located close to other electronic devices used in the home.