RadioMaster ER12 PWM - Dual-Band GEMINI and GEMINI-X Receiver
by RadioMaster

The RadioMaster ER12 PWM - Dual-Band GEMINI and GEMINI-X Receiver is a high-performance ExpressLRS receiver purpose-built for large-scale fixed-wing aircraft, demanding aerobatic models, and giant-scale gliders. Leveraging advanced GEMINI-X RF architecture, the ER12 concurrently operates on both 2.4GHz and Sub-G 900MHz frequencies to provide unparalleled signal reliability, long-range link penetration, and extreme interference rejection in congested RF environments.

The ER12 acts as a central distribution hub for complex RC planes, featuring 12 fully amplified PWM output channels that maintain robust signal integrity over long servo extensions. A dedicated XT30 power input connector delivers stable, high-current power directly to large or high-torque servos without straining the flight controller or receiver circuitry. With independent multi-source voltage telemetry—capable of monitoring the XT30 input, receiver PWM rail, and main flight batteries up to 70V—the ER12 gives pilots complete, real-time awareness of their aircraft’s power systems.

Key Features

• Dual-Band GEMINI-X RF System: Combines 2.4GHz and Sub-G 900MHz ExpressLRS technologies simultaneously for true diversity reception and maximum link stability.

• 12 Amplified PWM Outputs: Drives up to 12 servos directly, utilizing amplified signal outputs to prevent signal degradation across long servo leads.

• Dedicated XT30 Power Input: Provides a robust, high-current power delivery path (up to 12V) specifically designed to feed power-hungry multi-servo setups.

• Multi-Source Voltage Telemetry: Three independent ADC channels allow real-time monitoring of EXT-V (up to 70V), V-PWM/Receiver supply (up to 12V), and XT30 input (up to 12V).

• High-Power Adjustable Telemetry: Capable of outputting up to 100mW of telemetry power (adjustable via ELRS LUA script) for long-range data return.

• External UART & Serial Support: Features a dedicated external UART port for convenient connectivity, supporting CRSF and SBUS output for flight controllers and expansion modules.

• Wi-Fi Updates & WebUI: Allows for fast, wireless firmware flashing and configuration without removing the receiver from buried airframe installations.

• Rugged Injection-Molded Housing: The hard plastic enclosure and secure MMCX antenna connectors offer superior durability against crash impacts and airframe vibrations.

Technical Specifications

• Brand / Manufacturer: RadioMaster

• Model Identifier: ER12 PWM Dual-Band GEMINI-X Receiver

• Wireless Protocol: ExpressLRS (Requires ELRS firmware v4.1.0 or higher)

• RF Architecture: Dual-Band GEMINI-X (2.4GHz + Sub-G 900MHz)

• Output Channels: 12x PWM Channels

• Serial Protocol Support: CRSF / SBUS

• Input Voltage Range: 5.0V – 12.0V DC

• XT30 Input Voltage Detection Range: Up to 12.0V DC

• V-PWM (Receiver Supply) Detection Range: Up to 12.0V DC

• EXT-V (External Voltage) Detection Range: 4.0V – 70.0V DC

• Telemetry RF Power: Up to 100mW (Adjustable via LUA script)

• Antenna Connectors: MMCX (Secure, detachable)

• Antenna Type: 25cm High-Sensitivity Antennas

• Firmware Target: RadioMaster Dual 2.4GHz/900MHz Receiver

• Dimensions: 51.0 mm × 37.6 mm × 14.5 mm

• Net Weight: 22.5 grams (without antennas)

What Is Included

• (1) RadioMaster ER12 PWM Dual-Band GEMINI-X Receiver

• (2) 2.4GHz High-Sensitivity Antennas

• (2) Dual-Band High-Sensitivity Antennas

• (1) Voltage Telemetry Cable (Type-B)

• (1) CRSF Serial Cable

• (1) ELRS RX to SBUS Cable