【Brazil】 ANATEL issued Official Letter 81/2025

Last week, ANATEL issued Official Letter 81/2025 to clarify and harmonize the definition of indoor environments for the use of 5150-5350 MHz frequency range, particularly in vehicular applications, in accordance with items 3.1.48 and 11.2 of Act 14448.

(Click here to access Act 14448).

According to ANATEL, an indoor environment is defined as a space where building structures provide signal attenuation, thereby limiting radio emissions in multiple directions (see item 3.1.1 of Act 14448).

Based on this definition, ANATEL specifies that the 5150-5350 MHz frequency band (WLAN B1/B2) is permitted only in vehicles with a fully enclosed structure that mimics an indoor setting, such as cars and trucks. Consequently, this band is not allowed for use in open vehicles like motorcycles, tuk-tuks, or convertible cars.

See below the official letter text in English:

1. We acknowledge the receipt of letter OFFICIAL_SEI_COMMITTEE OCDS_057_25, registered under number 13205985, related to SEI Process 53500.006776/2025-25, in which the OCDs Committee requests guidance from Anatel regarding the applicability of items 3.1.48 and 11.2 of the Technical Requirements for the Conformity Assessment of Restricted Radiation Radiocommunication Equipment, as approved by Act No. 14448/2017, specifically in the context of motorcycles, tuk-tuks, and convertible cars.

2. As defined in subitem 3.1.1 of the Technical Requirements annexed to Act No. 14448/2017, a “closed environment (indoor)” refers to an environment capable of attenuating signals through structural penetration, thereby reducing transmission levels in multiple directions.

3. Subitems 3.1.48 and 11.2 further clarify:

Land transport vehicle: a vehicle intended to transport cargo or passengers, whose interior qualifies as a closed environment for the purposes of this regulation. This definition also includes trains.

11.2: The following provisions apply to access point transceivers operating in the 5,150–5,350 MHz frequency band, when installed inside land transport vehicles and trains.

4. Given these definitions and conditions, the vehicles in question — motorcycles, tuk-tuks, and convertibles — do not meet the criteria for a closed environment, as they lack physical barriers necessary to attenuate signal emissions in multiple directions. Therefore, the rules cited above do not apply to such vehicle types.

For further inquiries, please contact:

• Phone: +886-2-2602-9393

• Email: service@glodacert.co

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