siarez The schematic of the FSC-DH007-BT1104QI development board is not publicly released for the moment. For this reason, we do not advise connecting external devices directly to the header pins. Improper wiring may lead to signal conflicts or even damage the development board, with higher risks when the onboard USB-to-UART chip is working simultaneously.
If you need the schematic for hardware modification or project integration, please reach out to our technical support team via email: support@feasycom.com, and we will assist you accordingly.
For most common debugging scenarios, such as sending AT commands, we recommend using the Type-C port directly, with no extra external wiring required.
Thank you for your understanding.