Note: The difference between duplex and simplex: In duplex mode, there are 2 time slots, Tx and Rx can be done at the same time. Specification: Item Type: MMDVM Hotspot Board_x000D_Material: Iron_x000D_Color: Black_x000D_Support: for DMR, for YSF, for P 25, for D Star and System for Fusion_x000D_Mode: Duplex Mode and Simplex Mode_x000D_Radio Frequency: Support UHF 430-440MHz in Duplex Mode, Support Both UHF 430-440MHz and VHF 140-150MHz in Simplex Mode_x000D_Optimal Tuning: TX=0, RX=0, No Offset_x000D_Performance: High RF Performance_x000D_Antenna: 2 External Antennas_x000D_Fan: Cooling Fan on the Bottom_x000D_On Board LED Display Status: On Board LEDs Show Status, Status Wording on the Housing (TX, RX, PTT, Mode)_x000D_Memory Card: 8G (included) Features: 1Wide Compatibility: This Duplex MMDVM hotspot board supports for DMR, for P 25, for D Star and for System Fusion. works with for Orange PI and supports duplex mode and simplex mode. 2Easy Setup: Pre installed software for Pi Star on the memory card, no need to download again. Upgrade radio frequency (UHF: 430?440), no need to set for RXOFFSET and for TXOFFSET, they default to 0. 3Radio Frequency: MMDVM hotspot voard supports UHF 430?440MHz in duplex mode, UHF 430?440MHz and VHF 140?150MHz in simplex mode. optimal adjustment: tx=0, rx=0, no offset required. 4Easy Charging: Duplex hotspot board provides a free micro USB charging cable to charge with the power bank or connect to a laptop or computer. The hotspot can also work on the move in your car if you tether it to your cellular network. 5Note: When you flash the memory card with the new version of the software, please don't copy it directly on the memory card, please use the write tool to write the software on the memory card. PackageList: 1 xMMDVMHotspotBoard 2 x Antenna 1 x USB Cable 3 x Test Components