FCC Certification vs SDoC: intentional vs unintentional radiators

In the US, there is no single "FCC marking" equivalent to CE. Instead, Part 15 of the FCC's rules (47 CFR Part 15) splits electronic devices into two broad categories, intentional radiators and unintentional radiators, and routes each toward a different authorisation procedure. Knowing which one your product is decides whether you need a lab-tested, third-party-reviewed FCC Certification with an assigned FCC ID, or whether you can self-declare through a Supplier's Declaration of Conformity (SDoC).

Intentional vs unintentional: the actual distinction

An intentional radiator is a device that deliberately generates and emits radio-frequency energy to communicate: Wi-Fi, Bluetooth, cellular, RFID readers, remote controls, LoRa modules. These fall under 47 CFR Part 15 Subpart C.

An unintentional radiator is a device that does not intend to transmit RF energy at all, but generates it as a by-product of digital switching, clock circuits, or similar internal electronics, and that emitted energy needs to stay below defined limits so it does not interfere with other equipment. Most digital devices without a radio (a laptop, a desktop monitor, many appliances with a microcontroller) fall here, under Subpart B.

A device can be both: a smart speaker with Wi-Fi is an intentional radiator for its wireless radio and is also assessed for unintentional emissions from its other digital circuitry.

Intentional radiators: FCC Certification

Most intentional radiators require FCC Certification, the strictest of the FCC's equipment authorisation procedures. This requires testing at an FCC-recognised test lab, and in most cases review and grant by a Telecommunication Certification Body (TCB), an accredited third party authorised to issue certifications on the FCC's behalf. A successfully certified device is assigned a unique FCC ID, which has to be displayed on the device (physically or, for very small devices, electronically) and is publicly searchable in the FCC's equipment authorization database.

This is meaningfully different from CE self-declaration: for most intentional radiators, you cannot self-certify. A third party has to review your test data and grant the authorisation before you can market the device in the US.

Unintentional radiators: usually Supplier's Declaration of Conformity

Most unintentional radiators use the Supplier's Declaration of Conformity (SDoC) procedure. Since the FCC's 2017 rule modernisation, SDoC consolidated what used to be separate "Verification" and "Declaration of Conformity" procedures into a single, simpler self-declaration route: the responsible party has the device tested (at an accredited lab, though not requiring TCB review or FCC grant) against the relevant limits, keeps the test records on file, and includes a compliance statement with the product rather than an assigned FCC ID.

There is no FCC ID for a pure SDoC device. Instead, the required statement typically identifies the responsible party (usually the manufacturer or US importer) and, for devices that could cause harmful interference, an appropriate compliance notice. If you have ever seen "This device complies with Part 15 of the FCC Rules..." printed on a product without an FCC ID nearby, that is very likely an SDoC device.

The FCC ID label requirement

A certified device has to physically display its FCC ID, in a format defined by the FCC's rules, generally either a permanent label on the device itself or, where the device is too small or has no practical space for a physical label, an electronic label displayed through the device's own screen or a software menu, a rule the FCC formalised through its e-labelling provisions. There is no equivalent numbered ID for an SDoC device: the compliance statement identifying the responsible party is the closest analogue, but it is not a registration number and does not appear in the FCC's public equipment database the way a certified FCC ID does.

Modular transmitters change the maths

A common pattern in hardware design is buying a pre-certified radio module (a Wi-Fi or Bluetooth module that already carries its own FCC ID as a "modular transmitter") and integrating it into a larger host device. This can simplify certification of the radio function itself, since the module's grant already covers the RF performance, provided it is integrated according to the module manufacturer's specific installation and integration instructions. It does not automatically clear the host device of every other obligation: the host product, as a whole, is generally still evaluated as an unintentional radiator for its other digital circuitry, and in some cases the addition of a host enclosure, antenna change, or other design choice can affect whether the module's existing grant still applies without additional testing. Check the module manufacturer's integration guidance and, where in doubt, confirm with the test lab or TCB before assuming a certified module means a certified product.

Importing FCC-regulated devices

RF devices being imported into the US generally need to already hold the correct equipment authorisation, Certification or SDoC as applicable, before they can clear customs, and US Customs and Border Protection can require documentation confirming this at the border. This is a similar pattern to the EU and UK, where importer-level duties exist independently of what the manufacturer has already done; see our importing electronics from China piece for the wider picture across all three regions.

Why this matters for product planning

The practical consequence is timeline and cost: a device requiring Certification needs lab testing plus TCB review plus a grant before it can legally be marketed or imported, which adds real weeks to a launch schedule and a materially different cost profile than SDoC testing. Adding a radio to a previously radio-free product (turning an unintentional-radiator-only device into one with an intentional radiator too) is a common way startups discover late that their compliance path just got significantly stricter.

Where to check for your specific device

Whether a specific radio technology needs Certification, and under which specific rule part, is defined precisely in the FCC's equipment authorization rules and guidance, not by general category. The FCC's Office of Engineering and Technology publishes the authoritative guidance, and the TCB and accredited test-lab search tools let you find bodies qualified to test and certify your specific device. If your product also has a CE marking obligation for EU sale, note that FCC and CE testing address different (though sometimes overlapping) requirements, and one does not substitute for the other; see our CE marking requirements piece for that side.