Rear Data Pinout Diagram:
Connection to MMDVM V3F4,
Reference : http://www.digitalradiohacker.co.uk/digital-radio/tetra/tetra-terminals/motorola/mtm5400
MMDVM Device :https://www.bi7jta.org/shop/mmdvm-repeater-board-v3f4-dmr-ysf-d-star-nxdn-pocsag-fm-3#attr=63,27,117
DE BI7JTA