Rulemaking Overview and Purpose
In a Second Report and Order (FCC 07-56) adopted on April 17, 2007, and released on April 23, 2007, the Federal Communications Commission amended Parts 2 and 15 of its rules under ET Docket No. 03-201. The revised framework establishes codified equipment authorization procedures for both single-unit modular transmitters and partitioned (split) modular transmitter systems.
The amendments are intended to provide equipment manufacturers with flexibility in certifying transmitter modules, relieving them of the requirement to secure a new equipment authorization each time an approved transmitter is integrated into a different host product, while preventing harmful interference to authorized radio services.
- Docket: ET Docket No. 03-201
- FCC Order: Second Report and Order (FCC 07-56)
- Adopted Date: April 17, 2007
- Released Date: April 23, 2007
- Rule Addition: 47 CFR § 15.212
Codification of Single Modular Transmitter Requirements
The Commission codified the eight authorization criteria originally established in its June 26, 2000 Public Notice (DA 00-1407) into 47 CFR § 15.212. A single modular transmitter is defined as a completely self-contained radio-frequency transmitter device typically incorporated into another product, host, or device.
Under Section 15.212(a)(1), modular transmitters must meet eight baseline requirements to receive standard certification, though physical crystals and tuning capacitors may be placed external to the shielded radio elements.
- RF Shielding: Radio elements must possess their own radio-frequency shielding.
- Input Buffering: Buffered modulation/data inputs must be present (if provided) to avoid non-compliance from excessive data rates or over-modulation.
- Power Supply Regulation: The module must incorporate internal power supply regulation.
- Antenna Compliance: Compliance with Sections 15.203, 15.204(b), and 15.204(c) using permanent attachment or unique couplers; professional installation provisions do not apply to standard modular grants.
- Stand-alone Testing: Testing must occur in a stand-alone configuration with specific line lengths and AC line conducted compliance under Section 15.207 (unless battery-powered).
- Labeling: Display of an FCC ID on the module or host, with exterior reference labeling if internal labels are obscured.
- Operating Compliance: Compliance with all specific rule requirements, accompanied by detailed integration instructions.
- RF Exposure: Compliance with applicable RF exposure mandates under Sections 2.1091, 2.1093, and specific Part 15 rules.
Framework for Split Modular Transmitters
To support modular architectures where radio elements and control hardware are partitioned, the FCC established rules under Section 15.212(a)(2) for split modular transmitters. These systems consist of a radio front end with antenna and a transmitter control element (replacing the proposed term 'firmware').
Sections of a split modular transmitter must be tested together as a complete system inside a representative host platform and certified under a single FCC identification number. Mix-and-match combinations from different manufacturers are allowed only if the combined elements are tested and certified together.
- Shielding: Only the radio front end requires RF shielding; transmitter control elements do not require shielding.
- Digital Interface: The interface between split sections must be digital with a minimum signaling amplitude of 150 mV peak-to-peak.
- Data Exchange: Control information and operational data may cross the interface between the control element and radio front end.
- Security and Authentication: Split modules must incorporate authentication mechanisms (such as hardware coding or software electronic signatures) preventing operation unless the front end and control element verify they were authorized together.
- TCB Exclusion: Telecommunication Certification Bodies (TCBs) are initially excluded from certifying split modular transmitters until the FCC Laboratory acquires sufficient experience to issue operational guidance.
Limited Modular Approvals and Electronic Labeling
Under 47 CFR § 15.212(b), the Commission codified provisions for Limited Modular Approvals (LMA). Applicants whose modules do not meet every single-unit or split criterion (such as shielding, buffering, or power regulation) may obtain an LMA if they demonstrate alternative compliance methods and show how the grantee maintains control over the host installation to ensure end-product compliance.
The FCC also authorized electronic labeling for modular transmitters under terms similar to software-defined radios. Grantees may display the FCC ID electronically on a visible display or host screen, provided the user manual includes access instructions and the host exterior displays an advisory label indicating it contains certified modular equipment.
- LMA Scope: Applies when installation control is retained by the grantee or when compliance is established only for specific product configurations.
- Electronic Labeling Option: Allows FCC ID display via host software or electronic display alongside an exterior advisory notice.
- Responsibility: Grantees remain responsible for module compliance under the grant terms, while host assemblers remain responsible for non-compliant interactions or unauthorized module alterations.