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FCC CFR 47 Part 15B Radiated and Conducted Emissions 

The FCC CFR code is the electronic code of federal regulations. This part of the code sets out the regulations under which an unintentional radiator may be operated without an individual license. It also contains the technical specifications, administrative requirements and other conditions relating to the marketing of part 15 devices.

An unintentional radiator is defined as a device that intentionally generates radio frequency energy for use within the device. An unintentional radiator also sends radio frequency signals by conduction to associated equipment via connecting wiring, but which is not intended to emit RF energy by radiation or induction.

Numerous electronic products are subject to FCC CFR Part 15B testing. These products include the following:

  • Only those receivers that operate or tune within the frequency range of 30-960 MHz. CB receivers and radar detectors are subject to certain authorizations. Receivers operating above 960 MHz or below 30 MHz, except for radar detectors and CB receivers, are exempt from complying with the technical provisions of this part.
  • Personal computers are authorized in accordance with one of the following methods:
    • The specific combination of CPU board, power supply and enclosure is tested together and authorized under the Supplier’s Declaration of Conformity or a grant of certification.
    • The personal computer is authorized under the Supplier’s Declaration of Conformity or a grant of certification, and the CPU board or power supply in that computer is replaced with a CPU board or power supply that has been separately authorized under Supplier’s Declaration of Conformity or a grant of certification.
    • The CPU board and power supply used in the assembly of a personal computer have been separately authorized under Supplier’s Declaration of Conformity or a grant of certification.
  • CFR Part 15B EMC testing states that peripheral devices shall be authorized under Supplier’s Declaration of Conformity, or a grant of certification. This must occur prior to marketing. If a CPU board, power supply, or peripheral device will always be marketed with a specific personal computer, it is not necessary to obtain a separate authorization for that product. 

This is required when the specific combination of personal computer, peripheral device, CPU board and power supply has been authorized under the Supplier’s Declaration of Conformity or a grant of certification as a personal computer.

  • No authorization is required for a peripheral device or a subassembly that is sold to an equipment manufacturer for further fabrication. That manufacturer is responsible for obtaining the necessary authorization prior to further marketing to a vendor or to a user.
  • Power supplies and CPU boards that have not been separately authorized and are designed for use with personal computers may be imported and marketed only to a personal computer equipment manufacturer that has indicated, in writing, to the seller or importer that they will obtain Supplier’s Declaration of Conformity or a grant of certification for the personal computer employing these components.
  • Subassemblies to digital devices are not subject to the technical standards in FCC Part 15B testing unless they are marketed as part of a system. When that occurs, the resulting system must comply with the applicable regulations. Subassemblies are defined as the following.
    • Devices that are enclosed solely within the enclosure housing the digital device. There are exceptions, which include power supplies used in personal computers, peripheral devices and personal computer CPU boards.
    • CPU boards, other than those used in personal computers, that are marketed without an enclosure or power supply.
    • Switching power supplies that are separately marketed and are solely for use internal to a device other than a personal computer.

There are a number of devices that are exempted from CFR 47 Part 15B. However, the operator of the exempted device shall be required to stop operating the device upon a finding by the Commission or its representative that the device is causing harmful interference.

Operation shall not resume until the condition causing the harmful interference has been corrected. Although not mandatory, it is strongly recommended that the manufacturer of an exempted device endeavor to have the device meet the specific technical standards in this part. These exempted unintentional devices include the following.

  • A digital device utilized exclusively in any transportation vehicle including motor vehicles and aircraft.
  • A digital device used exclusively as an electronic control or power system utilized by a public utility or in an industrial plant.
  • A digital device used exclusively as industrial, commercial, or medical test equipment.
  • A digital device utilized exclusively in an appliance, e.g., microwave oven, dishwasher, clothes dryer, air conditioner (central or window), etc.
  • Specialized medical digital devices, generally used at the direction of or under the supervision of a licensed health care practitioner, whether used in a patient’s home or a health care facility.
  • Digital devices that have a power consumption not exceeding 6 nW.
  • Joystick controllers or similar devices, such as a mouse, used with digital devices but which contain only non-digital circuitry or a simple circuit to convert the signal to the format required. These devices are viewed as passive add-on devices, not themselves directly subject to the technical standards or the equipment authorization requirements.
  • Digital devices in which both the highest frequency generated and the highest frequency used are less than 1.705 MHz and which do not operate from the AC power lines or contain provisions for operation while connected to the AC power lines. 

It is important to note that equipment containing more than one device is not exempt from the technical standards in this part unless all of the devices in the equipment meet the criteria for exemption. If only one of the included devices qualifies for exemption, the remainder of the equipment must comply with any applicable regulations.

If a device performs more than one function and all of those functions do not meet the criteria for exemption, the device does not qualify for inclusion under the exemptions.

Keystone Compliance provides expert FCC CFR 47 Part 15B testing in a professional, timely and affordable manner. Our EMC test lab features multiple EMC test chambers. This ensures that lead times on scheduling are never an issue. In addition to EMC/EMI testing, our lab also features mechanical, product safety, wireless, ingress protection and package testing. Regardless of the testing need, Keystone Compliance can provide the appropriate solution.

For more information on our capabilities, please contact us. If you are ready to see firsthand why so many companies rely on Keystone Compliance for their FCC Part 15B EMC testing, please request a quote.