Mini Duplex Hat Hotspot Main Board for MMDVM Digital Modem Box Support Raspberry Pi and BlueDV

Mini Duplex Hat Hotspot Main Board for MMDVM Digital Modem Box Support Raspberry Pi and BlueDV

Description:
- MMDVM digital interphone modem (hotspot) box, through which she uses ordinary digital interphones to realize national interconnection, solves the restriction of the connection distance of ordinary digital interphones.
- MMDVM motherboard adopts imported components, temperature-compensated crystal oscillator, stable performance and low bit error rate after long-time startup.

Features:
- The new version of MMDVM duplex dual-time slot digital hot spot has the advantages of optimized wiring, perfect component layout, small heat generation, fast heat dissipation, etc., which is suitable for long-term startup work. The board has reserved two (old and new version interfaces) OLED screen interfaces, and one NXT serial port screen interface, which can be installed in multiple directions to make the screen more personalized. PCB antenna is adopted for small boards, and external antenna interface is also reserved. Duplex boards have the advantage of dual time-slots for DMR. All debugging parameters are based on the DMR system. Each board is carefully debugged. The calibrated DMR system will be more stable in use, and the sound quality reduction will be greatly improved. As for other systems, users can use the same stability as long as the frequency offset is slightly adjusted.
- This version needs to be used with Raspberry Pi. (By default, the row socket connected to Raspberry Pi is welded. The antenna base is not welded. If you need to weld, please contact in advance or leave a note. Thank you!)
- Duplex boards have the advantage of dual time-slots for DMR. All debugging parameters are carefully adjusted based on the DMR system. The calibrated DMR system will be more stable in use, and the audio quality reduction will be greatly improved. As for other systems, users can use the same stability in DMR, D-Star, YSF (C4FM), P25, NXDN, POCSAG, and other modes as long as the frequency offset is slightly adjusted.

Parameter:
- Frequency: U band (420.000-434.900/438.100-470.00/)
- Supported mode: DMR, D-Star, YSF (C4FM), P25, NXDN, POCSAG
- Power: 20mW
- Size: 65 x 30mm
- Supported Raspberry Pi: 2B/3B/3B+/4B/ZeroW
- For BlueDV with Type-C interface can be used to connect computers

The difference between Simplex and Duplex:
- Simplex can only work in direct frequency, just like the direct frequency intercom on the handset radio. Only one handset radio can talk to each other simultaneously.
- The duplex box can be like a relay station. The handset radio needs to set different frequencies for transmitting and receiving. The working principle of the duplex box is like a multi-mode digital relay station.
- The advantage of duplex box is to use DMR mode to talk at the same time without interfering with each other. One box can monitor two groups at the same time, and two groups can talk at the same time without interfering with each other. One duplex board is equivalent to two simplex boards. (Duplex board can also be set as simplex.)

Package Included:
- 1 x Mini Duplex Board