DRF4463D20 is a type of high performance data radio modem based on si4463 which is featured with high stability and long-term reliability of data transmission. The module can work at the default parameters. Users also can change the parameters such as RF output power RF data rate UART data rate Center frequency and parity check by microcontroller or computer through USB-to-TTL converter board. It provides 4 types of working modes for power-saving which can be realized by controlling the logic level of two I/O pins. The module supports wireless wake-up and the receiver function of module can be configured to wake up periodically to detect the wireless signal from transmitter. In the second mode users can control the AUX pin to get the RSSI value to check the reliabilty of wireless link. The part number in the picture is DRF4463D20-043A1 which has no LDO on board so it works in 2.1~3.6V. A product for Arduino that works with official Arduino boards.