The RadioMaster ER12 is a 12-channel PWM receiver designed for larger fixed-wing RC aircraft and installations requiring multiple servos, dedicated power distribution, and comprehensive voltage monitoring. Built on the ExpressLRS platform, it combines dual-band 2.4GHz and Sub-G 900MHz RF technology with amplified PWM outputs and flexible serial connectivity.

With a dedicated XT30 power input, three independent voltage-monitoring channels, and serviceable MMCX antenna connectors, the ER12 is designed to simplify receiver integration in complex aircraft builds while providing the control interfaces and power-monitoring capabilities needed for demanding installations.

Important Sales Restriction: Due to current FCC certification restrictions stated by the manufacturer, this product cannot currently be sold or shipped to the United States. Please check local regulatory requirements before ordering.

Features

• ExpressLRS Performance: Low latency, high reliability, and excellent link quality with flexible configuration options.
• Dual-Band Gemini-X RF System (2.4GHz + Sub-G 900MHz): Utilizes both frequency bands to provide enhanced link reliability across a wide range of operating environments.
• 12 PWM Outputs + Serial Support: Full 12-channel PWM output with dedicated bidirectional UART and serial interfaces for system integration and expansion.
• XT30 Dedicated Power Input: Provides stable, high-current power delivery for demanding servo systems and larger aircraft installations.
• PWM Signal Amplification: Amplified PWM outputs help maintain signal quality over long servo leads and extension cables. They also improve compatibility with larger, high-torque servos, helping ensure reliable control signal delivery throughout the aircraft.
• Independent Multi-Source Voltage Telemetry: Monitor up to three power sources simultaneously using dedicated ADC channels: EXT-V (up to 70V), receiver supply voltage (V-PWM) (up to 12V), and XT30 input voltage (up to 12V).
• External UART Port: Dedicated interface for telemetry, external devices, and system expansion.
• Wi-Fi Updates & WebUI: Configure settings and perform firmware updates wirelessly without disassembly.
• Robust MMCX Antenna Connectors: Secure, serviceable antenna connections for easy maintenance and long-term reliability.
• Durable Injection-Molded Housing: Provides consistent protection and structural durability for demanding installations.
• Application: Designed as a PWM receiver for large fixed-wing aircraft, especially where multiple servos and higher current loads are involved.
• Compatibility: Compatible with all ExpressLRS transmitters and modules, including radios with built-in ELRS.

Built on the ExpressLRS platform and equipped with dual Semtech LR1121 transceivers, the ER12 utilizes a dual-band Gemini X RF architecture operating on both 2.4 GHz and Sub-G 900 MHz. The result is a stable, consistent control link across a wide range of operating environments, with an architecture that prioritizes dependable operation.

The ER12 uses amplified PWM outputs to help maintain reliable servo signals over long leads and extension cables commonly used in larger aircraft. The amplified outputs also help ensure clean and consistent signals when operating larger, high-torque servos that place greater demands on the control system. The receiver also features three independent voltage telemetry channels with dedicated ADCs, allowing simultaneous monitoring of the receiver supply voltage (V-PWM) (up to 12V), the XT30 power input (up to 12V), and an EXT-V input for monitoring external battery voltages up to 70V. Serial connectivity is available via a dedicated 4-pin JST-GH locking UART/CRSF port for telemetry devices and other serial peripherals.

From installation to operation, the ER12 focuses on practicality, with a clean PCB layout to reduce interference, MMCX antenna connectors for easy serviceability, and a durable injection-molded housing built for long-term use. 

⚠️ XT30 Power Input Notice

XT30 Power Input:

The XT30 input supplies battery voltage directly to the receiver and PWM power rail. The output voltage follows the applied input voltage.

• Use only servos rated for the actual voltage supplied to the PWM rail.

• When using a 2S LiPo/Li-ion battery through the XT30 input, verify that all connected servos and equipment support the resulting voltage.

• Standard 5V servos must be powered from a suitable regulated 5V supply or the designated standard servo power input, as appropriate for the installation.

• When the XT30 input powers the receiver and servos, disconnect the ESC's 5V/BEC power wire to prevent back-feeding and potential damage.

EXT-V Power Input:

The EXT-V input uses a 2-pin JST-GH connector for external battery-voltage monitoring. Connect the red wire to the positive (+) terminal of the battery or ESC according to the official wiring instructions.

The EXT-V input is intended for voltage monitoring. Do not use it as the receiver's main power input.

Before powering the system, verify the wiring, input voltage, servo voltage ratings, and the official receiver wiring diagram.

Specification