Sample code for SIM800L and schematics

[ebelingtec]

just RXD and TXD by ESP32 or by SIM800L, TXD->RXD, RXD->TXD.
if sometimes can't work, just exchange the pin define will be ok.

From the ESP32-WROOM32E manual, pin 34 is type I=input, so it cannot be used for TX as I understand.

Name       No.       Type       Function
IO34        6         I           GPIO34, ADC1_CH6, RTC_GPIO4


Is there a way to switch the RXD and TXD pins on the SIM800L module with AT commands?