NBTC Regulatory Update: Wireless Microphones and DECT Technology
Scope and Impact
The National Broadcasting and Telecommunications Commission (NBTC) of Thailand has issued new technical standards for radio communication equipment to reflect technological advancements and ensure efficient frequency usage. These regulations impact manufacturers and importers of wireless microphones and Digital Enhanced Cordless Telecommunications (DECT) devices. The primary focus is on establishing updated technical parameters, safety requirements, and conformity assessment procedures for these device categories.
Digital Enhanced Cordless Telecommunications (DECT) - NBTC TS 1042-2568
This regulation covers digital radio communication systems utilizing DECT technology, including Fixed Parts (FP), Portable Parts (PP), Cordless Terminal Adapters (CTA), Wireless Relay Stations (WRS), and Hybrid Parts (HyP).
Permitted Radio Band: 1880 – 1900 MHz.
Maximum Transmitted Power: 250 mW (e.i.r.p.).
Technical Standards: Equipment must comply with ETSI EN 301 406 (V2.2.1 or newer) or the multi-part standards ETSI EN 301 406-1 and ETSI EN 301 406-2 regarding radio spectrum access and DECT evolution.
Wireless Microphone Equipment - NBTC TS 1006-2568
This standard applies to wireless microphones, in-ear monitoring systems, tour guide systems, and assistive listening devices. It introduces specific bandwidth limits and power constraints based on frequency ranges.
Frequency Bands and Power Limits:
88 – 108 MHz: Maximum 10 mW (Equivalent Isotropically Radiated Power). Restricted to use with vehicles.
165 – 210 MHz: Maximum 10 mW.
694 – 703 MHz, 748 – 758 MHz, and 803 – 806 MHz: Maximum 50 mW.
Bandwidth Restrictions: Maximum channel bandwidth is generally limited to 200 kHz. However, Wireless Multichannel Audio Systems (WMAS) are permitted a bandwidth of up to 8 MHz within the 694-806 MHz ranges.
Frequency Stability: Must not exceed ±20 ppm.
Spurious Emissions: Limits are defined based on frequency range, following ETSI EN 300 422-1 or FCC Part 15 Subpart C requirements.
Conformity Assessment
The conformity assessment categories are as follows:
Class A (Certification): Required for DECT equipment (1880-1900 MHz) and wireless microphones operating in the 694 – 703 MHz, 748 – 758 MHz, and 803 – 806 MHz bands. This involves full registration and approval by the NBTC.
SDoC (Supplier’s Declaration of Conformity): Permitted for wireless microphones operating in the 88 – 108 MHz and 165 – 210 MHz bands.
Relevant Testing Standards: ETSI EN 300 422-1 (Wireless Microphones), ETSI EN 301 406 (DECT), and ITU-R SM.329-13 for spurious domain emissions.
Electrical Safety and Radiation Exposure
All devices covered by these regulations must meet specified safety requirements to protect users:
Electrical Safety: Compliance with IEC 62368-1 (2018) or the equivalent Thai Industrial Standard TIS 62368 Part 1-2563 is mandatory.
Radiation Exposure: Equipment must comply with the NBTC’s safety standards regarding human exposure to electromagnetic fields (Health Safety).
Labeling Requirements
Radio communication equipment must be labeled according to the assigned conformity assessment class. Devices categorized as Class A require the official NBTC certification mark and registration number. Devices under the SDoC regime must maintain documentation proving compliance with the relevant technical standards, including the supplier's declaration.
Modification and Replacement
The regulation NBTC TS 1006-2568 for wireless microphones officially replaces the previous version, NBTC TS 1006-2560 (Technical Standards for Telecommunication Equipment and Devices for Wireless Microphone Radio Communication), which was issued on December 7, 2017. The new regulation updates the technical parameters and assessment procedures to reflect current spectrum management policies.
