[Hilo] Does the UART works in FULL-DUPLEX or HALF-DUPLEX?

Knowledge Base HL Series FAQ
1

Answer: The HiloV2 is FULL-DUPLEX, whatever in command mode or data mode.
Between AT command on RXD) and the answer on TXD, it is possible (but quite rare) that you get an URC on TXD.
If you want to disable URC, you can use the command AT*PSCHRU=0