IllustrationA BLE radio is an intentional radiator under Part 15 subpart C, and a granted module already covers its emissions, bandwidth, power and spectral density. The finished wearable's digital circuitry is an unintentional radiator under subpart B and still needs authorization. You also own labeling, RF exposure and the module's integration conditions.
If you plan a Bluetooth voice wearable, two parts of FCC Part 15 apply to the same product. A certified radio module settles one of them. This guide shows which part each piece of your design falls under and what you still own. It is an engineering summary of rule text and does not constitute legal advice. It also assumes a general wellness or voice product, and it is not a medical device guide. We quote the rules from a public mirror of the Code of Federal Regulations, as of October 31, 2026. Check the official eCFR text before you rely on any quote, and read the FCC guidance documents on modular transmitters and labeling, which we have not covered here.
What does each rule say?
| Rule | What it says | What it means for the wearable | Source |
|---|---|---|---|
| 15.3(o) and 15.3(z) | An intentional radiator deliberately emits RF energy by radiation or induction. An unintentional radiator makes RF energy for use inside the device but is not meant to emit it. | The BLE radio falls under the first definition (subpart C). The host digital circuitry falls under the second (subpart B). | Part 15.3 text, as of October 31, 2026 |
| 15.101 | Unintentional radiators must be authorized before marketing. Subassemblies are not subject to the technical standards unless marketed as part of a system, and then the resulting system must comply. | A granted radio module inside your wearable does not remove the host from subpart B. | Part 15.101 text, as of October 31, 2026 |
| 15.101(a) | The authorization table lists SDoC or Certification for Class B digital devices and other devices. It lists Certification only for scanning receivers, radar detectors and Access BPL. | A wearable host is a candidate for the SDoC or Certification route. Your lab confirms the class and route. | Part 15.101 text, as of October 31, 2026 |
| 15.212 | A single modular transmitter must have its own shielding, buffered modulation and data inputs, its own power supply regulation, and a permanently attached or unique-coupler antenna. It is tested stand-alone, carries its own FCC ID, and comes with instructions for the host maker. RF exposure compliance must hold in the final configuration. | You must stay inside the conditions the module was granted under. | Part 15.212 text, as of October 31, 2026 |
| 15.247 | For a 2.4 GHz digital modulation radio: a 6 dB bandwidth of at least 500 kHz, a conducted output limit of 1 Watt in 2400-2483.5 MHz, and a power spectral density no greater than 8 dBm in any 3 kHz band. | These radio limits are what the module grant already covers. | Part 15.247 text, as of October 31, 2026 |
| 15.19 | Sets the compliance statement text for Part 15 devices. A device too small to carry the label in 4-point font or larger may place it in the user manual and on packaging or a removable label when there is no e-label display. | Matters for small wearables such as rings and clips. | Part 15.19 text, as of October 31, 2026 |
Who owns what when you use a certified module?
This matrix is built from the rule text above. It contains no figures beyond the rules themselves.
| Item | Module grant | Host maker |
|---|---|---|
| Radio emissions, bandwidth, output power, power spectral density (15.247) | Covered by the module grant, when you use the module as granted | Keep the grant listing and confirm your design matches its conditions |
| Digital circuitry of the host (subpart B) | Not covered by the module grant | Yours: authorization of the finished wearable before marketing |
| Module integration conditions: antenna, power supply, shielding (15.212) | Defined by the grant | Yours: build the product inside those conditions |
| RF exposure in the final configuration (15.212) | Must hold in the final product | Yours: confirm with your lab for your wearable |
| Labeling: module FCC ID and 15.19 statement or e-label | Module carries its own FCC ID | Yours: put the module ID and the compliance statement on the finished product, or in the allowed alternative place for small devices |
How do you decide between reuse and a new grant?
Think of it as a flow. A certified module used inside its grant conditions leads to a subpart B authorization of your host. A changed antenna, a chip-down design or a split design leads to a new or modified grant. The lab makes the final call, so treat this as a way to prepare the conversation.
- Are we using the module exactly as granted, with a listed antenna and the supply the grant assumes?
- Do we plan any change to the radio, the antenna or the shielding?
- Is the radio built on our own board instead of a module?
- Is the radio split from the rest of the product in a way the grant does not describe?
What are the common traps?
These follow from the rule text above. They are engineering reasoning, and none describes an incident at any company.
- Treating the module grant as a finished-product grant. 15.101 says subassemblies are not subject to the technical standards unless marketed as part of a system, and then the system must comply. Our reading is that the host digital circuitry still needs authorization. Confirm with your lab.
- Changing the antenna. 15.212 requires a permanently attached or unique-coupler antenna for a modular transmitter. A different antenna than the one in the grant can put you outside the conditions the grant was issued under.
- A chip-down or split design. Modular treatment under 15.212 describes a self-contained transmitter with its own shielding, power regulation and buffered inputs. A design that spreads the radio across your own board is not that, so expect to need your own radio authorization.
- Forgetting the label on a tiny device. 15.19 allows the statement in the manual and on packaging when the device is too small for 4-point text and has no e-label display. Decide this early, because the enclosure drives it.
- Skipping RF exposure. 15.212 states that RF exposure compliance must hold in the final configuration. A body-worn product sits close to the user, so check this with your lab.
Note that 15.101 does not say in so many words that a host with a modular transmitter needs an SDoC. That follows from reading it with the rest of the section, and we have not read the FCC guidance documents on this point. Ask your lab.
What should you check on your own board?
The vendor grant tells you what was tested on the module. It does not tell you how your product behaves. Set the pass line yourself, based on your product requirements, and record the basis for it.
| What to test | How to probe or collect | Raw data to record |
|---|---|---|
| Antenna and module match | Compare the installed module part number, antenna and coupling against the grant listing and the integration manual. | Part numbers, antenna model, photos of the build, and the grant condition each item was checked against. |
| Power supply to the module | Probe the module supply rail on a running prototype in all operating modes, including charging. | Rail waveforms, mode list, firmware version, and the vendor condition you compared against. |
| Host digital noise | Have your lab scan the finished wearable with the radio active and with it idle. | Scan plots, set-up photos, firmware build, and a list of any clocks or interfaces you changed. |
| Final-housing behavior | Measure BLE output with the board inside the real enclosure, worn or held as in use. | Test set-up photos, orientation, and measured values with the unit under test identified. |
| Label placement | Mock up the final label or e-label on the real unit and the packaging. | Photos of the mock-up, text as printed, and font size you used. |
Anything the module vendor has not published, such as lab results for your enclosure, is vendor unpublished and needs to be measured on your board.
What should you ask the module vendor and your lab?
- Can we see the FCC grant listing for this module, and does it match the exact part number we will buy?
- Does the vendor provide an integration manual, and have we read every condition in it?
- Which antennas are listed on the grant, and is ours one of them?
- Does our design supply the module the way the grant assumes (power supply, shielding, data inputs)?
- Are we using the module as a stand-alone transmitter, or are we changing the radio design around it?
- Where will the module FCC ID and the compliance statement appear on a product this small?
- Which lab will confirm the subpart B route for our host, and what do they need from us?
- Who confirms RF exposure for the final wearable, and with what test set-up?
A note on voice and recording products
A wearable that records speech should tell people it is recording and should collect consent. Design a visible recording indicator from the start, because the indicator and the label both compete for space on a small enclosure.
Questions about Part 15B and 15C
Does a certified BLE module mean my wearable is already FCC approved?
No. The module grant covers the radio under subpart C. Under 47 CFR 15.101 (as of October 31, 2026), a subassembly marketed as part of a system means the system must comply. Our reading is that your host digital circuitry still needs authorization. Confirm the route with a lab.
What is the difference between 15B and 15C?
Subpart C covers intentional radiators, which deliberately emit RF energy. Subpart B covers unintentional radiators, which make RF energy for internal use. See 47 CFR 15.3, as of October 31, 2026.
What limits apply to the BLE radio itself?
For 2.4 GHz digital modulation, 15.247 sets a 6 dB bandwidth of at least 500 kHz, a 1 Watt conducted limit in 2400-2483.5 MHz, and no more than 8 dBm in any 3 kHz band, as of October 31, 2026. The module grant covers these.
My wearable is very small. Where does the FCC label go?
47 CFR 15.19 lets a device too small for 4-point text place the statement in the manual and on packaging or a removable label when there is no e-label display (as of October 31, 2026). Check the exact wording and the module ID rules with your lab.
Is this legal advice?
No. This is an engineering team's summary of the rule text, and it does not constitute legal advice. It is not a guide to medical device rules either: it assumes a general wellness or voice product. A recording product should have visible indication and user consent in its design. Tell us about your device and we will explain how we plan certification.
If you want to plan certification before you commit to a design, tell us about your device. You can also read how our gates and process bring FCC planning into Gate 0.
Sources
All pages accessed October 31, 2026. Rules change, so re-read the official text before you decide.
- 47 CFR 15.3, definitions: https://www.law.cornell.edu/cfr/text/47/15.3 (accessed 2026-10-31)
- 47 CFR 15.101, equipment authorization of unintentional radiators: https://www.law.cornell.edu/cfr/text/47/15.101 (accessed 2026-10-31)
- 47 CFR 15.212, modular transmitters: https://www.law.cornell.edu/cfr/text/47/15.212 (accessed 2026-10-31)
- 47 CFR 15.247, operation in 2400-2483.5 MHz: https://www.law.cornell.edu/cfr/text/47/15.247 (accessed 2026-10-31)
- 47 CFR 15.19, labeling requirements: https://www.law.cornell.edu/cfr/text/47/15.19 (accessed 2026-10-31)
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