Experimental setup consists of USB/TTL converter (1), attached to terminal emulator, ESP8266 Wi-Fi module (2), Arduino UNO board (3) and 100 Ohm resistor (4)*.
The steps of the experminent are as follows: 1) Start UDevTerm terminal emulator 2) Start Wi-Fi access point on terminal emulator 3) Attach USB/TTL converter (1) to Android Device OTG USB port, connect USB/TTL converter to terminal emulator 4) Connect Arduino UNO USB port to power 5) Configure USB/TTL converter connection with terminal emulator
Arduino UNO ESP8266 module sketch
6) Wait till ESP8266 module connects to UDevTerm terminal emulator Wi-Fi port, then configure Wi-Fi connection 7) Establish Bluetooth connection between UDevTerm terminal emulator and Teraterm PC terminal emulator (configure Teraterm to transmit CR+LF after each message) 8) Create bridge connection between Android Device OTG USB port and Bluetooth port 9) Send messages from Teraterm as an AT command to the TTL port of the ESP8266 module via Bluetooth. The ESP8266 module will send these messages to UDevTerm via Wi-Fi. First a message 14 characters long should be entered in Teraterm that ESP8266 module will send to UDevTerm over Wi-Fi. (Modify Arduino UNO module sketch to enter your access point name, password, etc.)
(*) Research have shown that if the ESP8266 module is connected to the Arduino UNO board via a TTL port, an additional 100 ohm resistor is required (4) to send a message from the Android terminal to the ESP8266 module via the TTL port. Otherwise, the ESP8266 module will not respond to messages sent from the Android terminal to it via the TTL port.