Telemetry using pprzlink protocol over FrSky X SmartPort serial link Downlink messages are sent on dataID 0x5015. Uplink is not implemented yet. Use the sw/tools/opentx-lua/sp2ser.lua script to receive these messages on the TX and forward them to the USB port. The ‘datalink’ script can read the pprzlink stream as a regular serial port. The data rate is very limited (max ~160 bytes/s). The limitation comes from the FrSky X protocol which can send at most 4 bytes of telemetry every 9ms. Set CC2500_TELEMETRY_SENSORS (from radio_control_cc2500_frsky) to SENSOR_NONE to maximize pprzlink throughput. Use a suitable telemetry conf for this low data rate.