In it, he shows an example of using all three ESP32 UARTs from an Arduino program. He calls the third port “secret” although that’s really a misnomer.

Now, with a serial bootloader and an ESP8266 in Wifi-to-serial bridge mode, you can reflash your microcontroller wirelessly, and then telnet in to interact with and debug the system remotely.

Connecting the Intel® Edison board to your Android* Phone with Serial Port Profile (SPP) describes how to connect your Edison board to Android* Phone with SPP, however, you cannot get the input ...