The 3DR Radio telemetry system is designed as an open source Xbee replacement radio set, offering a lower price, longer range (approx one mile) and superior performance to Xbee radios. It's available in 915Mhz and 433Mhz; and in the following configurations: serial board (for the air) and USB (for the ground).
The system provides a full-duplex link using HopeRF's HM-TRand data modules running custom, open source firmware. Interface to the module is via standard 5V-tolerant TTL serial / FTDI USB serial.
The SiK firmware includes a bootloader 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 the 3DR Radio configurator and AT commands.