OpenTX Transmitter Firmware Manual


The OpenTX firmware is the software that runs on compatible transmitters. It is the equivalent of an operating system.

Some of the community driven and supported features include:

  • Telemetry with advanced features
  • User configurable input and channel assignments
  • Mixes that allow for a large number of configurations
  • Actions configurable based on events and values
  • Announcement & Sound that are user configurable including adding custom audio files
  • Custom user images (depending on transmitter)

Download OpenTX

OpenTX is downloaded and installed (flashed) on to compatible transmitters using the Companion For OpenTX computer software. Read the Companion guide and install Companion.

Firmware Options

There are a number download (build) options selectable in Companion that will change the default firmware configurations and features available. For more information on this read the Transmitter Profile section of the Companion for OpenTX Guide.

Basic Concepts

Transmitter & Radio

In OpenTX the words transmitter and radio have been used interchangeably. Tx & TX are short forms of the word transmitter.

Transmitter Hardware’s Main Tasks

The transmitter has a computer, memory, a radio wave transmitting and receiving module, switches, knobs, buttons and control  sticks (Throttle, Elevator, Ailerons & Rudder).

The transmitter:

  • Receives pilot inputs from control sticks (Throttle, Elevator, Ailerons & Rudder) and switches and passes it to the firmware.
  • Transmits information from the firmware to the aircraft receiver.
  • Displays information from the firmware on a screen.
  • Receives telemetry from the aircraft receiver and passes it to the firmware.

Firmware’s Main Tasks

Hardware without software is like a human with a brain but without any knowledge, education and skills. All computer based transmitters require firmware (software) to be useful to a pilot.

The OpenTX firmware:

  • Manages the transmitter ‘s hardware resources.
  • Receives information from the transmitter hardware, processes it, and sends it back to the transmitter hardware.

Radio vs. Model Settings

Settings are grouped under two different sections in OpenTX as follows:

  • Radio Settings relate to the transmitter and the firmware running on the transmitter.
    • They are independent of the model being used.
    • Some examples are date, time, language and calibration.
  • Model Settings relate to the model being used.
    • Each model has its own settings independent of other models.
    • Some examples are receivers bound, timers, sensors and mixes.

Views, Menus & Settings

Screen Navigation & Editing Settings

When the transmitter is turned on the screen displays information. The transmitter has navigation and selection buttons on either side of the screen. There are over 30 screens that can be navigated using buttons on either side of the screen. More… 

Main View

The main view is the default view after the splash and warnings screens. This view shows information such as the model name, trim positions, transmitter battery voltage, flight mode and timer one. There are four main view screens. More…

Telemetry View

Telemetry screens are optional and are displayed if configured on the display screen under the model screens section. They display model information as numbers or bars, or display a Lua script’s screen. There may be up to four telemetry view screens. More…

Models Menus

The model menu screens select which model profile to use and relate to information, settings and actions for the current model in use. More…

Radio Menus

The transmitter menu screens relate to information, calibrations, configurations and actions that are independent of the model currently in use. More…

Sounds & Announcements

One of the main features of OpenTX is its use of a sound pack placed on a microSD card. This is one of the features that makes OpenTX user friendly and fun. More…

Using OpenTX Lua Scripts

OpenTX allows the addition of Lua scripts by the user to extend its abilities. More…

Keeping This Manual Up To Date

Please help keep this manual up to date. If you find that information is missing, incorrect on unclear please post on this manual’s thread in the Flite Test forum. More…

Examples & Mini Guides

Radio Menus

Model Menus



Images & Icons

Sounds & Announcements

Lua Scripts