RF Safety and Regulatory Spectrum Regulation Informational

What is the difference between Part 15, Part 90, and Part 95 FCC rules for RF devices?

Q: Can a Part 15 device interfere with a Part 90 device?

If a Part 15 device causes harmful interference to a Part 90 system: the Part 15 device must cease operation immediately (this is a legal requirement printed on every Part 15 device: "This device must accept any interference received, including interference that may cause undesired operation"). The Part 90 licensee can file an interference complaint with the FCC, and the FCC can require the Part 15 device manufacturer to address the issue (modify the device design, reduce power, or recall the product). In practice: Part 15 devices are designed to coexist with licensed services through: low power limits (the signal attenuates quickly with distance), spread spectrum (spreading the energy across a wide bandwidth reduces the interference density), and listen-before-talk (some protocols, like Wi-Fi, check for existing signals before transmitting).

Q: What is Part 18 vs Part 15?

Part 18: governs ISM equipment that generates RF energy for purposes other than communication (industrial heating, medical diathermy, scientific research). Example: microwave ovens (Part 18), RF welders, and MRI machines. Part 18 devices can produce much higher RF power than Part 15 (a microwave oven operates at ~1000 W). The emissions from Part 18 devices must stay within the designated ISM bands (2.4 GHz for microwave ovens). Out-of-band emissions must meet emission limits. Part 15: governs communication devices (Wi-Fi, Bluetooth) and unintentional radiators (computers, displays). Part 15 devices have lower power limits and stricter emission requirements than Part 18. Key difference: Part 18 is for non-communication RF energy generation; Part 15 is for communication and unintentional emissions.

Q: Do I need FCC certification for a prototype?

No. FCC certification is required for marketing and sale of the device, not for development and testing. During development: you can operate prototype devices under: the general exemption for development purposes (no specific authorization needed if the device is tested in a shielded lab or at very low power). An experimental license (Part 5: needed for over-the-air testing outside a shielded environment at power levels that might cause interference). Once the device is ready for production and sale: FCC equipment authorization (certification or SDoC, depending on the device type) is required before the first unit can be sold or offered for sale to the public.

FCC rules are organized into numbered Parts, each governing a different category of radio service. Part 15, Part 90, and Part 95 are three of the most commonly encountered rules for RF devices: (1) Part 15 (unlicensed devices): governs intentional and unintentional RF radiators that operate without an individual user license. Key characteristics: low power (typical limits: 1 W conducted for ISM bands, -41.3 dBm/MHz for UWB, much lower limits for other bands). No interference protection (Part 15 devices must accept all interference and must not cause harmful interference to licensed services). Equipment certification required (the device must be tested and authorized by the FCC before sale). Common Part 15 devices: Wi-Fi routers and access points (15.247), Bluetooth devices (15.247), UWB devices (15.517), RFID readers, garage door openers, baby monitors, and computer equipment (unintentional radiators, 15.107/15.109). Part 15 is the largest category by far (billions of devices). (2) Part 90 (Private Land Mobile Radio): governs licensed two-way radio communication systems for businesses, public safety, and other organizations. Key characteristics: individual station license required (the user must apply for and receive an FCC license for each radio system). Higher power allowed (up to 500 W for some VHF/UHF systems). Frequency coordination required (the user must coordinate with a frequency coordinator to avoid interference with other users on the same frequency). Interference protection (licensed Part 90 users have legal protection from interference). Common Part 90 devices: business two-way radios (Motorola, Kenwood), public safety radios (police, fire, EMS), trunked radio systems, and LTE-based push-to-talk systems. Part 90 is used by: utilities, construction companies, transportation, security, and government agencies. (3) Part 95 (Personal Radio Services): governs specific categories of personal radio communication that do not require an individual license (or require only a simple registration): GMRS (General Mobile Radio Service): up to 50 W on specific UHF frequencies. Requires a license (simple application, no exam). FRS (Family Radio Service): low-power (2 W max) handheld radios on specific UHF channels. No license required. CB (Citizens Band): 4 W AM or 12 W SSB on 27 MHz (40 channels). No license required. MURS (Multi-Use Radio Service): 2 W on specific VHF frequencies. No license required. Common Part 95 devices: FRS/GMRS walkie-talkies (Motorola Talkabout, Midland), CB radios, and MURS industrial radios.

Category: RF Safety and Regulatory

Updated: April 2026

Product Tie-In: Test Equipment, Filters

FCC Part 15 vs 90 vs 95

Understanding which FCC Part governs your device is the first step in the regulatory compliance process. Using the wrong Part can result in illegal operation and FCC enforcement action.

Comparison Table

(1) License requirement: Part 15: no user license. Part 90: yes, individual station license. Part 95: varies (FRS: no; GMRS: yes, simple; CB: no). (2) Power levels: Part 15: very low (mW to 1 W depending on band). Part 90: moderate to high (1-500 W). Part 95: low to moderate (2-50 W). (3) Interference protection: Part 15: none (must accept all interference). Part 90: yes (protected from harmful interference). Part 95: limited (depends on the specific service). (4) Equipment certification: Part 15: required (FCC ID). Part 90: required (FCC ID). Part 95: required for FRS and GMRS (FCC ID). (5) Typical use case: Part 15: consumer electronics, IoT, indoor/short-range. Part 90: professional two-way radio, public safety, business. Part 95: personal and family communication, recreational.

Choosing the Right Part

(1) If your device is a short-range wireless gadget (< 100 m range, consumer market): Part 15 (Wi-Fi, Bluetooth, Zigbee, UWB, or proprietary protocol). (2) If your device is a professional communication radio (dispatch, fleet management, public safety): Part 90 (licensed LMR, trunked radio, push-to-talk over LTE). (3) If your device is a personal handheld radio (family use, recreation): Part 95 (FRS for simple, GMRS for more range). (4) If your device is a cellular phone or base station: Part 24 (PCS), Part 27 (wireless communications), or Part 30 (upper microwave). (5) If your device is a satellite terminal or earth station: Part 25 (satellite). (6) If your device is a radar: Part 15 (low-power automotive radar at 77 GHz), or Part 90 (licensed radar). (7) If your device uses the ISM bands for industrial/scientific purposes (not communication): Part 18 (Industrial, Scientific, and Medical equipment).

FCC Part Comparison

Part 15: no license, low power, no protection
Part 90: licensed, higher power, protected
Part 95: varies by service (FRS/GMRS/CB)
P15 ISM: up to 1W/30dBm conducted
P90 UHF: up to 500W for some services

Common Questions

Frequently Asked Questions

Can a Part 15 device interfere with a Part 90 device?

If a Part 15 device causes harmful interference to a Part 90 system: the Part 15 device must cease operation immediately (this is a legal requirement printed on every Part 15 device: "This device must accept any interference received, including interference that may cause undesired operation"). The Part 90 licensee can file an interference complaint with the FCC, and the FCC can require the Part 15 device manufacturer to address the issue (modify the device design, reduce power, or recall the product). In practice: Part 15 devices are designed to coexist with licensed services through: low power limits (the signal attenuates quickly with distance), spread spectrum (spreading the energy across a wide bandwidth reduces the interference density), and listen-before-talk (some protocols, like Wi-Fi, check for existing signals before transmitting).

What is Part 18 vs Part 15?

Part 18: governs ISM equipment that generates RF energy for purposes other than communication (industrial heating, medical diathermy, scientific research). Example: microwave ovens (Part 18), RF welders, and MRI machines. Part 18 devices can produce much higher RF power than Part 15 (a microwave oven operates at ~1000 W). The emissions from Part 18 devices must stay within the designated ISM bands (2.4 GHz for microwave ovens). Out-of-band emissions must meet emission limits. Part 15: governs communication devices (Wi-Fi, Bluetooth) and unintentional radiators (computers, displays). Part 15 devices have lower power limits and stricter emission requirements than Part 18. Key difference: Part 18 is for non-communication RF energy generation; Part 15 is for communication and unintentional emissions.

Do I need FCC certification for a prototype?

No. FCC certification is required for marketing and sale of the device, not for development and testing. During development: you can operate prototype devices under: the general exemption for development purposes (no specific authorization needed if the device is tested in a shielded lab or at very low power). An experimental license (Part 5: needed for over-the-air testing outside a shielded environment at power levels that might cause interference). Once the device is ready for production and sale: FCC equipment authorization (certification or SDoC, depending on the device type) is required before the first unit can be sold or offered for sale to the public.

Keep Reading