Introduction: What Is a Long-Range Wireless Audio Transmission Module?
In industrial automation, security monitoring and command & dispatch, wireless voice communication is the key to efficient response and real-time coordination. Traditional walkie-talkie solutions are bulky, power-hungry and hard to integrate, making them unsuitable for the strict voice-communication requirements of embedded devices.
A wireless audio transmission module is purpose-built to solve this. It integrates an RF transceiver, audio codec, MCU and necessary peripheral circuits into a small module that communicates via standard MIC input and speaker output interfaces, quickly enabling wireless voice between devices. Users do not need deep RF/audio expertise — just add a simple audio circuit and an antenna to build a complete wireless intercom system.
The EWM201-470A20S / EWM201-470A30S from Chengdu EBYTE Electronic Technology Co., Ltd. are two all-new long-range wireless audio modules operating in the 470–510MHz band with both half-duplex and full-duplex support. They are ideal for digital walkie-talkies, building intercoms and command-and-control systems.
Who Needs It: Solving Real-World Pain Points
The EWM201-470AxxS series serves four core user groups:
| User Group | Typical Profile | Core Pain Point | Module Solution |
|---|---|---|---|
| Digital walkie-talkie makers | Product managers, hardware engineers | Long dev cycles, complex RF design, high cost — hard to ship new products fast | Highly integrated voice module — just add MIC, speaker, antenna and power to build a walkie-talkie; cuts cycle time and R&D cost |
| Building intercom integrators | Security contractors, system integrators | Need wireless intercom for residents with long range, strong penetration and full-duplex | 470MHz UHF penetrates walls well; 3.5km/5km open-air range; full-duplex for real-time two-way calls |
| Command & control engineers | Public safety, emergency dispatch engineers | Need a flexible, reliable, wide-coverage wireless voice dispatch system with point-to-point and point-to-multipoint | Unicast, multicast and broadcast; half/full-duplex switching to fit different scenarios |
| Wireless audio solution providers | System integrators, product managers | Need stable, low-latency voice transmission for smart voice systems and wireless alarm systems | Time-slot TDD mechanism with precise slot control and scheduling for real-time, stable voice |
Product Overview
Series Overview
The EWM201-470A20S/EWM201-470A30S are all-new long-range wireless audio modules from EBYTE, transceiver-in-one, with flexible configuration, easy use and a compact footprint. They operate in the 470–510MHz band; users can configure TX power, working channel, UART rate and other parameters via commands. The modules support MIC input and speaker output, and point-to-point / point-to-multipoint half-duplex or full-duplex modes. Just add MIC, audio amplifier, speaker, antenna and power to build a full-duplex walkie-talkie.
Version Comparison
| Parameter | EWM201-470A20S | EWM201-470A30S |
|---|---|---|
| Positioning | Standard power, best value | High power, ultra-long range |
| Max TX power | 20dBm | 30dBm |
| Reference range | 3.5km (open air) | 5km (open air) |
| Supply voltage | 2.4V ~ 3.6V (≥3.3V recommended) | 2.4V ~ 5.5V (≥3.7V recommended) |
| TX current | ≈94 mA (instantaneous) | ≈680 mA (instantaneous) |
| Size | 16 × 26 mm | 26.5 × 33 mm |
| Interface | Stamp hole (1.27mm pitch) | Stamp hole (2.00mm pitch) |
| Key strengths | Small size, low power, easy integration | Ultra-long range, strong penetration |
Features & Model Comparison
Core Features
Domestic chip solution: Built on a domestic narrowband IoT transmission technology — stable supply chain, secure and controllable.
Half/full-duplex switchable: Configure via AT commands to flexibly switch between half-duplex and full-duplex voice, fitting different applications.
Ultra-long range: Under ideal conditions with battery power, up to no less than 3.5km (20S) / 5km (30S) in open-air tests.
All-software voice compression: Wide code-rate range, improves spectrum efficiency and reduces interference.
Flexible network topology: Supports unicast, multicast and broadcast intercom for point-to-point and point-to-multipoint.
Industrial-grade design: Long-term operation at -40℃ ~ +85℃ for harsh environments.
Dual antenna options: Supports IPEX/stamp-hole dual antenna interfaces for easy secondary development and integration.
Model Comparison
| Feature | EWM201-470A20S | EWM201-470A30S |
|---|---|---|
| Frequency band | 470–510 MHz (configurable) | 470–510 MHz (configurable) |
| Air rate (full duplex) | ≤29.8kbps | ≤29.8kbps |
| Air rate (half duplex) | ≤14.9kbps | ≤14.9kbps |
| RX sensitivity (full duplex) | -121dBm (29.8kbps) | -121dBm (29.8kbps) |
| RX sensitivity (half duplex) | -124dBm (14.9kbps) | -124dBm (14.9kbps) |
| Modulation | DPFSK | DPFSK |
| TX power | ≤20dBm (software adjustable) | ≤30dBm (software adjustable) |
| RF interface | IPEX / stamp hole (50Ω) | IPEX / stamp hole (50Ω) |
| Supply voltage | 2.4V ~ 3.6V (≥3.3V recommended) | 2.4V ~ 5.5V (≥3.7V recommended) |
| TX current | 91~95 mA (typ. 94mA) | 365~910 mA (typ. 680mA) |
| RX current | 28~32 mA (typ. 30mA) | 28~32 mA (typ. 31mA) |
| Operating temp | -40℃ ~ +85℃ | -40℃ ~ +85℃ |
| Package | SMD | SMD |
| Interface | Stamp hole (1.27mm pitch) | Stamp hole (2.00mm pitch) |
| UART | 921600bps 8N1 | 921600bps 8N1 |
| Size | 16 × 26 mm | 26.5 × 33 mm |
Technical Parameters
RF Parameters
| RF Parameter | EWM201-470A20S | EWM201-470A30S |
|---|---|---|
| Frequency band | 470–510 MHz | 470–510 MHz |
| Air rate (full duplex) | ≤29.8kbps | ≤29.8kbps |
| Air rate (half duplex) | ≤14.9kbps | ≤14.9kbps |
| RX sensitivity (full duplex) | -121dBm | -121dBm |
| RX sensitivity (half duplex) | -124dBm | -124dBm |
| Modulation | DPFSK | DPFSK |
| TX power | ≤20dBm | ≤30dBm |
| RF interface | IPEX / stamp hole (50Ω) | IPEX / stamp hole (50Ω) |
Electrical Parameters
| Main Parameter | EWM201-470A20S | EWM201-470A30S |
|---|---|---|
| Supply voltage (V) | 2.4 ~ 3.6 (3.3 recommended) | 2.4 ~ 5.5 (3.7 recommended) |
| Operating temp (℃) | -40 ~ +85 | -40 ~ +85 |
| Operating humidity (%) | 10 ~ 90 | 10 ~ 90 |
| TX current (mA) | 91 ~ 95 (typ. 94) | 365 ~ 910 (typ. 680) |
| RX current (mA) | 28 ~ 32 (typ. 30) | 28 ~ 32 (typ. 31) |
Hardware Parameters
| Hardware Parameter | EWM201-470A20S | EWM201-470A30S |
|---|---|---|
| Package | SMD | SMD |
| Interface | Stamp hole (1.27mm pitch) | Stamp hole (2.00mm pitch) |
| Communication | UART (AT commands) | UART (AT commands) |
| UART config | 921600bps 8N1 | 921600bps 8N1 |
| Size | 16 × 26 mm | 26.5 × 33 mm |
Application Scenarios
Digital Walkie-Talkie
Recommended: EWM201-470A20S (lightweight, low power) / EWM201-470A30S (long range, strong penetration)
Build a digital walkie-talkie around the EWM201 module with a MIC, audio
amplifier, speaker, antenna and battery. The module supports half- and
full-duplex; users switch TX/RX via a PTT key for clear, low-latency
voice. The 30S's 5km range covers large construction sites, scenic areas
and parks.
Building Intercom System
Recommended: EWM201-470A20S (enough for indoor coverage)
Embed the EWM201 module into indoor units and door entry hosts. The
470MHz band penetrates floors and walls well, enabling full-duplex
wireless calls between indoor units and entry hosts. The broadcast
function enables batch delivery of property notices.
Command & Control System
Recommended: EWM201-470A30S (high power, long range)
In emergency command and security dispatch, use the module's multicast
and broadcast functions to build a flexible dispatch network. The
command center broadcasts instructions to all terminals; terminals
communicate point-to-point via multicast or unicast. The 30S's 5km range
covers large events and emergency sites.
Wireless Alarm & Security System
Recommended: EWM201-470A20S (low power, small size)
Embed the EWM201 module into alarm hosts and detectors (IR, door
magnet). When a detector triggers, the module transmits alarm voice
wirelessly to the host for voice alarm. Its low power suits
battery-powered detectors.
FAQ
Poor Transmission Range
Line-of-sight obstructions attenuate range accordingly.
Temperature, humidity and co-channel interference increase packet loss.
Ground absorption/reflection: testing near the ground degrades performance.
Seawater strongly absorbs RF; testing near the coast performs poorly.
Metal objects near the antenna or a metal enclosure heavily attenuate the signal.
Incorrect power-register settings or excessive over-the-air rate (higher rate = shorter range).
Supply below the recommended level — lower voltage reduces TX power.
Poor antenna–module matching or low antenna quality.
Module Easily Damaged
Check the supply is within the recommended range; exceeding the maximum can permanently damage the module.
Ensure supply stability — avoid large, frequent voltage fluctuations.
Follow ESD precautions during installation; high-frequency components are ESD-sensitive.
Keep humidity in check during installation; some components are moisture-sensitive.
Unless necessary, avoid operation at extremes of temperature.
How to Quickly Evaluate the Module?
Purchase the official EWT201-470A20S/EWT201-470A30S test kit from EBYTE. Based on the EWM201 intercom module, it supports Type-C power, AT-command configuration and a 3.5mm headphone jack. Just connect an antenna and power to run quick tests, greatly shortening the development cycle.
About EBYTE
Founded in 2012, Chengdu EBYTE Electronic Technology Co., Ltd. is a national high-tech enterprise integrating R&D, production and sales. Headquartered in Chengdu with offices in Shenzhen, Guangzhou, Shanghai and Beijing, it serves customers in over 100 countries and regions worldwide. EBYTE focuses on industrial IoT wireless communication, with a portfolio spanning wireless modules, radio modems, industrial gateways, network I/O, industrial PCs, antennas and accessories.
Technology philosophy: EBYTE is committed to the mission of "making wireless communication simpler and the IoT world smarter," delivering stable, high-performance, cost-effective wireless voice products and solutions that drive industrial automation and intelligence.
Choosing the EBYTE EWM201-470AxxS series means choosing a professional, reliable, high-efficiency wireless voice communication platform.
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