Japan’s Ministry of Internal Affairs and Communications (MIC) has amended the Radio Equipment Regulations to expand the transmission speed options available to Inmarsat-D type radio equipment used in Inmarsat mobile earth stations. Ordinance No. 84 of 2026, issued under Article 38 of the Radio Act and dated June 30, 2026, took effect on the date of promulgation. The amendment adds a new set of higher data rate options, ranging up to 25,600 bits per second, alongside the equipment’s existing 600 and 1,800 bps setting. Manufacturers and operators of Inmarsat-D satellite terminals now have a clear technical pathway to certify equipment capable of significantly faster data transmission in Japan.
What Changed: New Transmission Speed Options for Inmarsat-D Equipment
The amendment revises Article 49-24, Paragraph 3 of the Radio Equipment Regulations, which sets the technical conditions for Inmarsat-D type radio equipment operating on G1D radio waves. Previously, the transmission speed for this equipment was limited to automatic selection between 600 bps and 1,800 bps. The revised rule keeps that original setting in place and adds a second, newly established option: automatic selection among 1,600 bps, 3,200 bps, 6,400 bps, 12,800 bps, or 25,600 bps. Equipment manufacturers can now design and certify devices against either speed profile, depending on the application.
Understanding Inmarsat-D and G1D Emission Radio Equipment
Inmarsat-D is a global satellite messaging service that supports low-cost, two-way, store-and-forward data communications, widely used for asset tracking, remote telemetry, and supervisory control and data acquisition (SCADA) applications, including maritime and land-based monitoring. The equipment affected by this update transmits using G1D emissions, an ITU designation for phase-modulated, single-channel digital data intended for telemetry and data transmission. Raising the maximum available transmission speed by more than tenfold gives Inmarsat-D terminals the capacity to move substantially more data per transmission, supporting more detailed telemetry, more frequent reporting intervals, and more data-intensive monitoring applications.
Effective Date and Certification Requirements
Ordinance No. 84 took effect immediately upon its promulgation on June 30, 2026, with no separate implementation delay. Radio equipment intended to use the new higher-speed transmission options must be certified against the amended technical conditions set out in Article 49-24, Paragraph 3 of the Radio Equipment Regulations. Manufacturers seeking to bring updated Inmarsat-D terminals to the Japanese market should review their equipment’s transmitter design against the newly added speed profile ahead of certification submissions.
Transitional Provisions: Existing Certifications Remain Valid
The ordinance includes a grandfathering provision for equipment already on the market. Technical conformity certifications and construction design certifications granted under the prior version of Article 49-24, Paragraph 3, for Inmarsat-D type radio equipment used in Inmarsat mobile earth stations, remain valid after the ordinance’s effective date. Holders of existing certifications are not required to recertify equipment that continues to operate under the original 600/1,800 bps transmission speed setting.
Impact on Satellite Equipment Manufacturers and Japan's Market
For manufacturers of Inmarsat-D satellite communication equipment, the update removes a technical ceiling that previously capped certified transmission speeds at 1,800 bps. Equipment makers targeting Japan can now pursue certification for terminals designed around the higher-speed profile, supporting applications that require faster data throughput without sacrificing the reliability of Inmarsat’s store-and-forward network. Combined with the transitional provisions preserving existing approvals, the change gives both new entrants and established suppliers a predictable path forward in the Japanese market.
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Quick Country Facts
Japan
Certification Body: Ministry of Internal Affairs and Communications (MIC)
Certification Type: Mandatory
License Validity: Indefinite
Application Language: English
Legal License Holder: Manufacturer
In-Country Testing Requirement: In-Country Testing
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