[Free tools](/free-tools)/[United States](/free-tools/us)/Pre-certified module checker

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# Using a certified radio module? See what FCC work is left

A certified module saves you a transmitter certification — not all FCC work. Five questions show what's left for your host product.

What kind of approval does the module have?

It's on the module's FCC grant (search its FCC ID).

Full modular approvalLimited modular approval (LMA)Not sure

Are you using an antenna type and gain listed in the module's grant?

YesNo

How close to people is the antenna in normal use?

20 cm or more (mobile use)Under 20 cm, or worn on the body (portable use)

Does the product have another transmitter that can operate at the same time?

YesNo

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## How this works

A pre-certified (modular) transmitter has its own FCC ID, so the radio doesn't need certifying again when it goes into your product — as long as you stay inside the conditions on its grant. Those conditions cover the antenna, how close the antenna sits to people, and whether other transmitters run alongside it.

Your product still needs its own authorization for unintentional emissions from everything else on the board, usually by SDoC, and a label stating which module it contains.

## Questions

### Do I need FCC testing if I use a certified module?

Yes, for the rest of the product: its digital circuitry needs Part 15 Subpart B testing and an SDoC. The module's grant only covers the transmitter.

### What's the difference between full and limited modular approval?

A full modular approval can be used in any host within the grant conditions. A limited modular approval restricts use to hosts the grantee has approved.

### Can I change the antenna?

Only to an antenna of the same type and equal or lower gain than those listed in the grant. Anything else usually needs a Class II permissive change or a new FCC ID.

## Related guides

*   [FCC Equipment Authorization: Certification vs SDoC Explained](/guides/fcc-equipment-authorization)
*   [FCC KDB (Knowledge Database): How to Use It for Equipment Authorization](/guides/fcc-kdb-guide)
*   [FCC Part 15 Subpart B: EMC Emission Rules for Unintentional Radiators Explained](/guides/fcc-part-15-subpart-b-emissions)
*   [FCC SDoC (Supplier's Declaration of Conformity): Complete Guide](/guides/fcc-sdoc-supplier-declaration)

Regulatory information based on your answers and the sources listed, not legal advice. Krono is not a notified body, test lab or law firm; you remain responsible for your product's compliance.