Features:1. This board needs to cooperate Raspberry Pi PI3, orange pie, a variety of school development board to use.2. This board has been applied in the GM300 GM3188 3688 950I 338 Vitex DR-1X, other types of repeaters and car stations need to be studied yourself.3. The MMDVM is intended to be an open-source Multi-Mode Digital Voice Modem, which utilities the power of an ARM processor and a simple analogue interface board.4. The Multi-Mode Digital Voice Modem is a combined hardware and software development of a modem to handle all amateur digital voice modes. Initially it will support D-Star and DMR, with System Fusion and P.25 coming later, as well as a built-in FM repeater controller. For all modes other than DMR and FM, the modem can be used in simplex or duplex mode, while for DMR and FM full duplex must be used.5. The MMDVM is aimed at the Arduino Due, Teensy 3.1/3.2 and mbed platforms, the only requirement for the hardware is to be ARM Cortex-M3, M4, or M7 based, and access to raw interrupts and ADC and ADC ports as well as digital signalling ports.Specification:Size: about 6.6*5.7*2cm/2.6*2.24*0.79inColor: GreenMaterial: PCBPackage List:1 * Relay Board for Raspberry Pi1 * Moto Cable2 * Adapter 1 * Instruction ManualNote: It can't work for Raspberry Pi 3B+, can't use the nextion LCD display.