Tera 3DRobotics 3DR Radio Telemetry Kit 433Mhz Module for APM APM2.5 2.6 Pixhawk PX4 The radio is a 2way half duplex wireless communication system with a standard TTL UART interface, based on HopeRF's HMTRP data link modules, and custom firmware that improves upon the modules' original features and performance. The SiK firmware includes a boot loader that permits radio firmware upgrades over the serial interface, and radio firmware with configurable parameters. Firmware upgrades and configuration are fully supported in the APM Mission Planner. Configuration is also possible through AT commands. 3DR Telemetry Kit. Receiver sensitivity to 121 dBm. Transmit power up to 20dBm (100mW). Transparent serial link.