Digital Devices and Unintentional Radiator Emissions

Identify whether the equipment meets the applicable definitions and whether an express exemption applies. Class A and Class B digital-device definitions distinguish relevant commercial or industrial marketing from residential use. Class A should not be selected merely because the purchaser is a business. A product intended for homes can remain Class B even when some units are also used in a workplace.

Section 15.101 specifies authorization pathways by device type. Many covered digital devices can follow Supplier's Declaration of Conformity or certification, while specified equipment requires certification. The table and exemptions must be read together. Avoid assuming that absence of an intentional transmitter removes every FCC obligation, or that every electronic product must display an FCC ID associated with a certification grant.

Subpart B includes conducted and radiated emission requirements. The relevant frequency ranges, limits, measurement arrangements and operating conditions must match the equipment category. Select representative operating modes and supporting equipment under the applicable procedures. Testing a bare board can provide development information, but does not automatically establish conformity of a finished product with different housing, wiring, power conversion or attached peripherals.

The technical record should identify the model, circuit and enclosure version, power supply, relevant cables, peripherals and operating software. These details help explain why a measured result represents the equipment offered for sale. If special accessories are needed to comply, the applicable rules and instructions must be addressed. A supplier's report for a similar assembly is insufficient without a documented connection to the actual product.

Part 15 addresses identification, compliance statements, instructions and information appropriate to the equipment. Class-specific interference information and any necessary installation conditions should reach the user in the prescribed form. A generic logo does not replace those requirements. Review packaging, manuals and model descriptions together so the declaration, responsible-party information and equipment identity remain consistent through distribution.

A new processor clock, display, power supply, cable arrangement or enclosure can affect emissions. Review changes before reusing earlier evidence and preserve the basis for any decision that further testing is unnecessary. Part 15 operation also carries interference conditions. Conformity of the tested configuration does not establish electrical safety or guarantee interference-free operation in every installation; field complaints require their own technical assessment.