At time of writing there is no user feedback about conflicting ports. We need to connect to the serial programming interface of the ESP8266 chip. within the code. Select option P6 - serial. It has been widely used for decades. Typical PC mouse controlling system has the following parts: sensors -> mouse controller -> communication link -> data interface -> driver -> software. On Windows these interfaces are named COM1, COM2, etc. Serial5, Supported only on Teensy 3.0 - 3.6. RS232 serial port monitoring hardware stands out for a number of reasons, including its 9 pin RS232 pinout. The positive power supply usually taken from RTS and DTR lines (just after the diodes and before the resistor going to leds). Start raspi-config: sudo raspi-config. Change COM5 with your port designation. For the purpose of simplicity only the Windows version will be explained here, but the commands and parameters are the same for Windows, Linux and Mac. Mouse send data to computer in levels that RS-232C receiver chip in the computer can uderstand as RS-232C input levels. button for the initial configuration of your device instead of webUI. answer 'No' At the prompt Would you like the serial port hardware to be enabled? Depending on the phone, it will take you to the Tasmota configuration page automatically, or you will get a prompt to *sign in to Wi-Fi network* or *authorize*. Sample transmission shown on picture: Start bit (active low, usually between +3v and +15v) followed by data bits, parity bit (depends on protocol used) and finished by stop bit (used to bring logic high, usually between -3v and -15v). You may want to back up the device manufacturer's firmware on the one in a million chance you don't like Tasmota. Ensure the device is in flash mode before each step. On Teensy 3.2, 3.5, 3.6, Serial1 and Serial2 have 8 byte transmit and receive FIFOs, To put the ESP8266 into Programming Mode: You can test whether your device is in Programming Mode by attempting to read information from the ESP82xx chip. In 7 and 8 bit modes, this function is the same as write(byte). Choose according to your jumper wire connectors. All serial ports on Teensy 4.0 and 4.1 have 4 byte transmit and receive FIFOs. Teensy 3.0, 3.1, 3.2 support 9 bit mode on Serial1, Serial2 and Serial3. Because typical optomechanical mouse also needs power for 4 leds in the optocoupler movevement detectors, there is not much power to loose. Just be sure to remove the GPIO0 to GND bridge before booting the device for regular operation. Implement the RTS toggle function by setting the RTS line negative and positive again. COM Port Pinout and Configuration RS232 manages communication flowing between the DTE and DCE using serial pinouts of either the DB9 or DB25 variety. Check its description page. The following use COM5 as an example. For example, for direct connection to FRSky SPort telemetry, normally inverters and diode OR externally would be required. Now is the time to set up [MQTT](MQTT.md) and the last remaining, but equally important, step: #### Configure Template or Module Configure your device using [Templates](Templates.md) in **Configuration - Configure Template** or [Modules](Modules.md) in **Configuration - Configure Module**. The serial ports support many different kinds of interfaces and peripheral. *In this example [Termite](https://www.compuphase.com/software_termite.htm) on Windows is used. When you have identified pins on your device, connect wires according to the table: Note that TX from your adapter goes to RX on the ESP8266 device and RX from adapter goes to TX on the device! Configure module-specific parameters (i.e. Mouse controller reads the state of those sensors and takes acount of current mouse position. a MAX232 or similar chip is needed. This PC serial port interface is single ended (interconnect  two devices only, via RS232 serial cable), the data rate is less than 20 kbps. Change COM5 with your serial port designation. is use of code designed for Arduino Uno with tip If you're not using a second Wi-Fi network you can enter an SSID without a password you can connect to as a backup in case something went wrong with your Wi-Fi credentials. Esptool is the official Espressif tool for flashing ESP8266 chips. If you have followed Hardware preparation, your device should be in Flash Mode and ready for a Tasmota firmware binary file to be flashed. This requires esptool.py. These first 2 ports also run from a higher To support these signal types, as well as the signal ground, the RS-232 standard defines a 25-pin connection. EEPROM The bit D6 in the first byte is used for syncronizing the software to mouse packets if it goes out of sync. This function must be called after Serial1.begin(); The RTS output from Teensy should be connected to the CTS input on will create a baud rate with only -0.79% error, which exactly matches Teensy. It is send to the computer every time mouse state changes (mouse moves or keys are pressed/released). If you did publish instruction for Do-It-Yourself device with this pinout. Supply more power with a separate 3.3V power supply or get an adapter with a better power supply. #### Configure MQTT Look in your router for a newly connected device with the same name as the Wi-Fi access point. Sensors are the movement detectors which sense the mouse movement and button swiches which sense the button states. If you miss the window you might have to disconnect your device from power and reconnect.