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Koshiro1130
Visitor II
August 13, 2026
Solved

Japanese certification scope of NUCLEO-WL55JC1 (018-210191) for 2-FSK/GFSK

  • August 13, 2026
  • 1 reply
  • 75 views

Hello,

ST Customer Support advised me to post this question in the ST Community.

I am planning to use a NUCLEO-WL55JC1 (MB1389) as a transmitter in Japan. According to the official ST Japan certification list, this board has Japanese radio certification number 018-210191:

https://www.stmcu.jp/technical/hint/no-119/

The Japanese certification database shows the following information:

  • Emission designation: G1D

  • Frequencies: 920.6 to 928.0 MHz

  • Channel spacing: 200 kHz, 38 channels

  • Antenna power: 16.0 mW

However, the Avnet Japan product page states that the certification applies only to LoRa and Sigfox modulation:

https://www.avnet.com/japan/products/product-highlights/stmicroelectronics-nucleo-wl55jc/

I need to determine whether certification 018-210191 also covers custom 2-FSK or 2-GFSK transmission.

Could an ST employee or someone familiar with the certification documents please clarify the following?

  1. Does certification 018-210191 cover 2-FSK or 2-GFSK transmission?

  2. If it does, what are the certified values or permitted ranges for:

  • Frequency/channel

  • FSK or GFSK modulation

  • Data rate

  • Frequency deviation

  • Gaussian BT

  • Occupied/transmit bandwidth

  • Antenna power for each channel

  • Permitted antenna

  • Carrier-sense time and threshold

  • Maximum transmission duration and required off-time

  • Identification-code or packet-format requirements

  1. Can custom STM32CubeWL firmware and a custom packet format be used while remaining within certification 018-210191, provided that all certified RF parameters, carrier-sense requirements and transmission-time restrictions are preserved?

Our current reference configuration is:

  • Frequency: 922.200 MHz

  • Modulation: 2-GFSK

  • Data rate: 10 kbps

  • Frequency deviation: +/-25 kHz

  • Gaussian BT: 0.7

These exact parameters are not mandatory. The receiver is based on a CMT2219A and can be reconfigured, so we can change the frequency, data rate, deviation, BT and bandwidth to match an already-certified 2-FSK or 2-GFSK parameter set.

I understand that the STM32WL hardware is technically capable of FSK/GFSK. My question is specifically about the legally certified operating scope of Japanese certification 018-210191.

If custom FSK/GFSK firmware is not covered, please clarify which official firmware, binary or protocol configuration must be used to remain within the certification.

Thank you.

Best answer by Pat_ST

Hello,
Concerning question 1: The NUCLEO-WL55JC1 (MB1389) Japanese radio certification number 018-210191 does not cover custom 2-FSK or 2-GFSK transmission. Indeed, as the SubGHz radio systems handle many modulations and transmission systems protocols, it is very huge (even impossible) to cover all modulations and transmission systems protocols (including many frequencies, data rates, deviations, BT and bandwidths to match an already-certified modulation parameter set).
Only the radio parameters/modulations used in the NUCLEO-WL55JC1 (MB1389) Japanese radio certification are covered by the certification number 018-210191.

Based on question 1 answer, the question 2 is not applicable.

Concerning the question 3: A custom STM32CubeWL firmware and a custom packet format can not be used within certification 018-210191.

Nervertheless, keep in mind that both LoRa & Sigfox modulations are the most restrictive ones in term of RF certifications, which means that as soon as LoRa and/or Sigfox certifications have been passed, all the other modulations such as 2-FSK or 2-GFSK will pass RF certifications with a very high level of confidence.

Hope this will answer to your questions.
Best regards
 

1 reply

Pat_ST
Pat_STBest answer
ST Employee
August 21, 2026

Hello,
Concerning question 1: The NUCLEO-WL55JC1 (MB1389) Japanese radio certification number 018-210191 does not cover custom 2-FSK or 2-GFSK transmission. Indeed, as the SubGHz radio systems handle many modulations and transmission systems protocols, it is very huge (even impossible) to cover all modulations and transmission systems protocols (including many frequencies, data rates, deviations, BT and bandwidths to match an already-certified modulation parameter set).
Only the radio parameters/modulations used in the NUCLEO-WL55JC1 (MB1389) Japanese radio certification are covered by the certification number 018-210191.

Based on question 1 answer, the question 2 is not applicable.

Concerning the question 3: A custom STM32CubeWL firmware and a custom packet format can not be used within certification 018-210191.

Nervertheless, keep in mind that both LoRa & Sigfox modulations are the most restrictive ones in term of RF certifications, which means that as soon as LoRa and/or Sigfox certifications have been passed, all the other modulations such as 2-FSK or 2-GFSK will pass RF certifications with a very high level of confidence.

Hope this will answer to your questions.
Best regards
 

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