Part 15 rules limit the amount of conducted RF (radio frequency) energy that may be injected into a building's wiring by an RF device that receives power from the commercial power source, including carrier current systems that couple RF energy onto the AC wiring for communication purposes. This conducted energy can cause harmful interference to radio communications via two possible paths. First, the RF energy may be carried through the electrical wiring to other devices also connected to the electrical wiring. Second, at frequencies below 30 MHz, where wavelengths exceed 10 meters, long stretches of electrical wiring can act as an antenna, permitting the RF energy to be radiated over the airwaves. Due to the low propagation loss at these frequencies, such radiated energy can cause interference to other services at considerable distances.
The FCC has a long history of facilitating the introduction of new technologies under Part 15 of its rules. For example, in the mid-1980s, the Commission provided new rules to spread spectrum technology that led to the growth of an industry and a wide array of products. In the past few years, the Commission has amended Part 15 to provide for unlicensed personal communication service (UPCS) devices, unlicensed national information infrastructure (U-NII) devices and millimeter wave technology.