Digi XBee 3 Cellular LTE-M User Manual page 266

API frames
Use an external processor to output the frame over the UART with the BLE interface as a
n
target. This outputs the data contained in the frame as the Output Frame over the active BLE
connection via indication.
An external processor outputs the Frame over the UART with the Micropython interface as a
n
target. Micropython operates over the data and publishes the data to mqtt topic.
Digi XBee® 3 Cellular LTE-M/NB-IoT Global Smart Modem User Guide
User Data Relay - 0x2D
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