I have small ESP 12F (ESP8266) module and I can not get it to work. I have used many other modules like Wemos successfully, I can program. I understand that for very basic functionality test the ESP 12F needs to be connected to external 3.3V power source (I use battery) and TX/RX pins to UART-USB converter. Also ground of UART and external power is connected. With this setup and with terminal set to 78440 baud, CR+LF, the ESP 12F should respond to AT commands.
When I issue AT, I get some unknown character in response (⸮). I get this for baud rates from 38400 to 500000. Under 38400 I dont get anything at all, for baud 1000000 I get "Q R" as response and for baud 2000000 I get "Q5R" as response to AT.
So I think that the module can respond, but bits returned are not understood.